a speech by Daniela Corsini

Abstract

In 2020, the Covid-19 epidemic disrupted global supply chains and boosted demand for safe-haven assets. In 2021, the global gold market should benefit from a rebound in jewelry demand and a supportive macroeconomic environment amid expansionary monetary policies, low interest rates and a pick-up in inflation expectations.

Commodities: hit by Omicron and monetary policies

The negative impact of the Omicron variant and the threat of more restrictive monetary policies now represent the worst headwinds for commodity markets and could trigger deeper corrections in market prices in the near term. However, temporarily weaker commodity prices would clearly benefit the global economy, contributing to an acceleration in growth rates, and simplify the task of the main central banks, which could continue supporting the global recovery instead of fighting commodity-driven inflationary pressures.

The macroeconomic outlook remains weaker than earlier expected due to persistently high inflation pressures, and concerns about a quicker than earlier expected pace of tightening from the Federal Reserve. In addition, the unexpected spread of the Omicron variant forced downward revisions to estimates about global commodity demand, further delaying the recovery in some sectors, like the aviation industry, or worsening the prospects of global supply chains due to the persistent threat of logistic bottlenecks and lockdowns.

In our opinion, the negative impact of the Omicron variant and the threat of more restrictive monetary policies now represent the worst headwinds for commodity markets and could trigger deeper corrections in market prices in the near term.

However, temporarily weaker commodity prices would clearly benefit the global economy, contributing to an acceleration in growth rates, and simplify the task of the main central banks, which could continue supporting the global recovery instead of fighting commodity-driven inflationary pressures.

According to our baseline scenario, after a probable, deeper correction in early 2022, most commodities could resume a path of modest price increases. In fact, market prices of crude oil and non-ferrous metals could recover part of the lost ground as soon as central banks reassure markets and global economic growth consolidates.

In 2022, specific supply and demand fundamentals should come back as core drivers of commodity prices, prevailing over macroeconomic factors, and volatility should be mainly fuelled by news flows about supply disruptions, delays across the logistic chains and forecasts about future consumption patterns, especially in China.

In the medium- and long-term, we still forecast a bullish trend for industrial metals, while natural gas and energy prices should gradually decrease, maintaining their usual seasonal swings.

Forecasts for the commodities universe

Crude oil. Given the recent weakening in crude oil supply and demand fundamentals and concerns about a quicker pace toward restrictive monetary policies, we revised downwards our estimates for crude prices in 2022. In our opinion, a temporary correction could push Brent near an average of USD 65 in 1Q22. Then, upward pressures on crude prices could resume strength driven by more optimistic forecasts about global crude demand, thanks to a seasonal increase in fuel consumption and, hopefully, easing concerns about the development of the epidemic. Thus, we envisage a rising trend in crude prices from the 2Q22 onwards. In our baseline scenario, we now forecast that on average Brent should record a level of USD 67.5 in 2022 and USD 70 in 2023. Volatility should remain an important market feature and will often contribute to amplify intra-day market movements.

Energy. Although the extreme conditions faced by global gas and power markets ahead of the 2021/22 winter are unlikely to repeat every year, we can expect further moments of market stress and more volatility on energy prices, as the necessary and ineluctable transition toward cleaner energy sources proceeds and the penetration of renewable energies progresses.

Precious metals. In 2021, all the main precious metals have fallen in price. We maintain a negative view on both gold and silver, as we think that the headwinds of more restrictive monetary policies will continue to weaken appetite for both metals on financial markets. On the contrary, we now expect that platinum and palladium could recover part of their recent losses, as demand from the automotive sector should pick up thanks to the easing semiconductor shortage.

Industrial metals. After the unexpected spread of the Omicron variant and talks about a quicker pace of tightening from the Federal Reserve, the risk of a deeper correction in most industrial metals’ prices intensified and now we see lower prices in 1Q22. However, later in 2022 specific supply and demand fundamentals should come back as core drivers of metals’ prices, and non-ferrous metals’ prices should recover ground. In the medium- and long-term, we still forecast a bullish trend for industrial metals.

Agricultural products. Agriculture is the most supply-elastic commodity sector. Thus, the high prices recorded in 2021 should contribute to expand supplies in 2022, when possible, and could trigger widespread price declines in anticipation of the next harvest season. However, unusual weather patterns remain the most worrying threat and could fuel volatility due to deeper and less predictable impacts of climate change and global warming on the sector.

Precious metals: we favour palladium vs. gold

In 2021, all the main precious metals have fallen in price. We maintain a negative view on both gold and silver, as we think that the headwinds of more restrictive monetary policies will continue to weaken appetite for both metals on financial markets. On the contrary, we now expect that platinum and palladium could recover part of their recent losses, as demand from the automotive sector should pick up thanks to the easing semiconductor shortage. Thus, in a medium-term strategic asset allocation we would favour palladium vs. gold.

In 2021, all the main precious metals have fallen in price. Gold and silver suffered downward pressures due to a stronger U.S. dollar and announcements from the main central banks anticipating tighter monetary policies. In fact, expectations of higher rates discourage investments in gold and other non-interest-bearing assets as they increase their opportunity cost. We maintain a negative view on both metals, as we think that the headwinds of more restrictive monetary policies will continue to weaken appetite for gold on financial markets. Currently, silver isn’t strong enough to decouple from gold despite the promising fundamentals in the long term.

In the second half, platinum and palladium prices also dropped, as the global shortage of semiconductors had a deeper than expected negative impact on global vehicle production and thus on consumption of both metals. Prices probably bottomed and we now expect that platinum and palladium could recover part of their recent losses, as demand from the automotive sector should pick up thanks to the easing semiconductor shortage.

In our baseline scenario, we envisage a consolidation in global growth and a gradual easing of bottlenecks and semiconductor shortage. Monetary policies should tighten, but remain supportive of the global economic recovery as long as necessary. Thus, in a medium-term strategic asset allocation we would favour palladium vs. gold.

Gold

The latest data published by the World Gold Council (WGC) show that appetite for gold on financial markets further deteriorated during 3Q21 as monetary policies were tightening and the Fed progressed toward the planned tapering.

Considering ETFs’ holdings as a proxy for gold appetite on financial markets, at the end of September global holdings were close to 3,600 tons, as the sector had recorded outflows worth about 156 tons since January 2021, the largest decline since 2013. In 3Q21, ETFs’ gold holdings decreased by about 27 tons, thus ETFs’ contribution to gold demand turned negative during the quarter, representing a net loss worth about 2% of global demand. It is a remarkable change in market sentiment, when considering that ETFs’ flows were a positive contributor worth about 4% of global consumption in 2Q21 and covered a stunning 40% of demand in 2Q20.

Given the relevance of ETFs’ flows, in 3Q21 global gold demand contracted by 7% y/y, although all non-financial components of gold demand rose. In fact, a recovery in global economic growth boosted gold consumption in the jewellery (+33% y/y) and technology sectors (+7% y/y), while higher saving rates, concerns about inflation risks and uncertainty about epidemiological developments fuelled demand for bars and coins (+18% y/y). In the official sector, a renewed appetite in diversifying official reserves supported gold demand. In fact, central banks turned from net sellers of gold in 3Q20 to net buyers of the precious metal in 3Q21.

Given the current expectations of tighter monetary policies and still robust global growth, over the next quarters the non-financial components of gold demand may extend their recovery, and we envisage higher purchases from the jewellery, technology and official sectors. On the contrary, gold-backed ETFs could suffer from more outflows due to an increase in the opportunity cost of holding gold, amid expectations of higher yields and threats of higher benchmark interest rates.

According to our baseline model, we forecast that gold could average about USD 1,770 in 1Q22 and could decline toward a USD 1,720 average in 2022. Despite the unfavourable monetary framework, we envisage only moderate downside pressures on gold prices thanks to the important support of the ongoing recovery in the jewellery sector, which should gain support from global growth, and of the official sector, as central banks could take advantage of lower gold prices to diversify their reserves. In addition, inflation concerns could limit the volumes of ETFs’ outflows.

Given the exceptionally high level of uncertainty that clouds the macroeconomic framework due to unpredictable development in epidemiological risks, record high energy prices and persistent bottlenecks negatively affecting logistic chains and manufacturing activities, our forecasts remain subject to significant risks.

The worst-case scenario for gold would be a macroeconomic environment characterized by a further acceleration in global growth, thanks to fading epidemiologic concerns, easing bottlenecks and a strong commitment from central banks to intervene and prevent the economy from overheating. In fact, under this scenario investors would favour cyclical assets against safe haven assets, while higher interest rates would also discourage gold holdings. Under such worst-case scenario, gold could quickly drop toward a USD 1,450 support.

On the contrary, the best-case scenario for gold would be a macroeconomic environment characterized by a deterioration in the prospects for global growth, possibly driven by a spreading epidemic coupled with scarcely effective vaccines. Central banks would be forced to postpone a planned tightening of monetary conditions in an effort to support their economies, while bottlenecks to logistic and supply chains would persist, fuelling inflation pressures. Under such extreme scenario of stagflation, gold could retest its peaks above USD 2,000.

Silver

According to our baseline model, silver should trade close to an average price of USD 24 an ounce both in 1Q22 and in 2022. We expect that the metal could remain most of the time in a trading range between USD 21 and USD 27 an ounce.

Relative to gold, silver should maintain higher volatility, but it will not probably be strong enough to decouple from the yellow metal. Thus, silver will probably follow gold’s downward trajectory over the next years despite positive fundamentals and expectations of expanding global demand, especially in green technologies.

We expect that the gold/silver ratio could remain slightly above its long-term average over the next years, as the long-term positive correlation between silver and gold should remain significant, despite the support granted to silver by the green transition.

Platinum and palladium

Our forecasts for platinum-group metals (PGM) are strictly connected with expectations about a possible recovery in the automotive sector and thus with developments in the semiconductor crisis. In fact, according to estimates from Johnson Matthey, about 85% of palladium demand comes from autocatalysis mainly used in vehicles mounting gasoline-powered engines, while more than 30% of platinum demand comes from autocatalysis mainly used in vehicles mounting diesel-powered engines.

In 2021, PGM have gone through a boom and bust cycle. In fact, in the first half platinum and palladium overperformed other precious metals because car manufacturers quickly expanded their purchases to restock their warehouses and satisfy new vehicle orders, despite the first signs of disruptions to global supply chains due to semiconductors’ shortage.

Then, as time passed, and the global recovery consolidated, semiconductor scarcity deepened and forced car manufacturers to scale down their output plans and even halt some production facilities. As a consequence, PGM demand faded. Several car producers revised downwards their output guidance, fuelling pessimism on financial markets and raising doubts about future consumption growth for platinum and palladium in the sector.

Now, car producers are probably adequately supplied to meet their medium-term needs of PGM. Thus, so far low prices have failed to attract consumers due to still uncertain estimates about future vehicle production. In the longer term, although we still see ample room for a recovery in prices, probably the upward potential for PGM prices has been structurally lowered by the semiconductor crisis, as the current delays in PGM consumption patterns imply more time for global PGM supply to satisfy demand and more time for secondary supply to flow back in the market thanks to a pick-up in recycling activities.

Our baseline scenario now assumes an average platinum price of USD 1,025 an ounce and an average palladium price of USD 2,000 an ounce in 1Q22. We forecast that in 2022 platinum could trade near a USD 1,075 average and palladium near a USD 2,050 average.

In our opinion, palladium probably bottomed in late November, as USD 1,700 should represent a strong support for the metal. On the contrary, the USD 950 low reached in November is a weaker support for platinum, and we see the level of USD 900 as a more solid floor.

We maintain a bullish view in the long term (albeit forecast numbers have been revised downward from previous forecasts due to longer and deeper than expected disruptions along the supply chain) because we expect that the semiconductor crisis could ease in 2022, following plans to expand the global output of microchip, and both vehicle production and global demand for PGM should pick up.

Appendix

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Valuation Methodology

This document has been prepared in accordance with the following method.

Macroeconomic Data
Comments on macroeconomic data are prepared based on macroeconomic and market news and data available via information providers such as Bloomberg and Refinitiv-Datastream. Macroeconomic and interest rate forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated econometric models. Forecasts are obtained using analyses of historical-statistical data series made available by the leading data providers and also on the basis of consensus data, taking account of appropriate connections between them.

Forecasts in the Energy Sector
Comments on the Energy Sector are prepared based on macroeconomic and market news and data available via information providers such as Bloomberg and Refinitiv-Datastream. Unless otherwise stated, consensus estimates come from the leading international energy Agencies, primarily the IEA (International Energy Agency – which deals with this sector on a global scale), the EIA (Energy Information Administration – an institute that deals specifically with the US energy sector) and OPEC. Forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated models.

Forecasts in the Metals Sector
Comments on the Metals Sector are prepared based on macroeconomic and market news and data available via information providers such as Bloomberg and Refinitiv-Datastream.
Unless otherwise specified consensus estimates on precious metals come mainly from GFMS, the long-established forecasting agency based in London. The forecasts cover gold, silver, platinum and palladium. Forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated models.
Unless otherwise stated, consensus estimates for industrial metals come mainly from Brook Hunt, an independent forecasting agency which has prepared statistics and predictions on metals and minerals since 1975, and from the World Bureau of Metal Statistics (WBMS), an independent research body on the global market of industrial metals which publishes a series of monthly, quarterly and annual statistical analyses. Forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated models.

Forecasts in the Agricultural Sector
Comments on the Agricultural Sector are prepared based on macroeconomic and market news and data available via information providers such as Bloomberg and Refinitiv-Datastream.
There are several consensus estimates on agricultural products. Each individual country has its own internal statistics agency that estimates and forecasts crops, production capacity, the product supply quantities and, above all, the amount of land available for cultivating a particular product, in both absolute and percentage terms.
At an international level, the main agencies are: the USDA (United States Department of Agriculture) which, in addition to providing data on the US territory, also deals in general with the grain industry worldwide through the FAS (Foreign Agricultural Service); the Economist Intelligence Unit of the Economist Group which deals with all agricultural products on a global scale; and CONAB (Companhia Nacional de Abastecimento), the Brazilian Government agency that deals with agriculture (with a particular focus on coffee) and which also provides some insight into the entire South America.
Forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated models.

Technical levels
Comments on technical levels are based on market news and data available via information providers such as Bloomberg and Refinitiv-Datastream. Interest rate technical level forecasts are prepared by the Intesa Sanpaolo Research Department, using dedicated technical models. Forecasts are obtained using analyses of historical-statistical data series made available by the leading data providers and also on the basis of consensus data, taking account of appropriate connections between them. There is also a further in-depth study linked to the choice of appropriate derivatives that best represent the sector or the specific commodities on which one intends to invest.

Recommendations
Negative Outlook: a Negative Outlook recommendation for a sector is a wide-ranging indication. It not only indicates deteriorating price conditions of the indices or futures that best represent the commodity in question (thus the reduction of a price performance), but it also implies the deterioration in the forecasts on production, weather and input supplies (like water or energy) that characterize these sectors more than other financial instruments.
Neutral Outlook: a Neutral Outlook recommendation for a sector is an indication that includes a multitude of aspects. It indicates that the combination of price forecasts of indices and futures and all the conditions of production, weather and input supplies (like water or energy) will lead to a sideways movement in prices or inventories or production capacity, recording, therefore, void or minimum performances for the sector under examination.
Positive Outlook: a Positive Outlook recommendation for a sector is an indication covering a wide range of areas. It not only indicates net improvements in price conditions of the indices or futures that best represent the commodity in question (thus a positive price performance), but it also implies the improvement in the forecasts on production, weather and input supplies (like water or energy) that characterize these sectors more than other financial instruments.

Frequency and validity of forecasts

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a speech by Carlo Buckhardt

Abstract

In order to overcome existing restraints in the in-service behaviour of currently available additive manufacturing (AM) materials’ sets, an advanced production method for high performance technology metals was developed on the basis of a modified vat polymerisation-based (VP) printing for metal powders. The new lithography-based metal manufacturing (LMM) process is able to photoharden highly filled innovative metal-photopolymeric binder.
After debinding and sintering, the fully dense metal AM parts will provide various advantages such as superior properties with respect to cracks or internal stress when compared to laser-based powder bed fusion (L-PBF) AM parts. LMM is suitable to build very detailed, complex structures with a minimum of after-treatments without need for support structures, exhibiting superior surface quality, having less demanding requests with respect to powder particle size/morphology and allowing effective re-use of the feedstock materials.
In the paper, the LMM process will be explained in detail, its suitability for the production of jewellery and watch pieces will be demonstrated for stainless steel type materials and titanium alloys on various samples, an outlook for precious metal powders will be given

Pforzheim University

• founded 1899
• one of the biggest Universities for Applied Sciences in Germany (~6.000 students)
• threefaculties:
  Business, Economics & Law
  Engineering
  Design
• 29 Bachelor-and 17 Master-Courses
• one of 7 fully certified universities in Germany

Institute for Precious and Technology Metals

Partner oftheregional precision engineering industry

• contract research, serial inspections, damage analyses, expert opinions, production optimisations, etc.
• fully equipped materials lab; incl. 2 SEM, FIB, EDX/XRD, Laserscan, DTA, mechanical testing, corrosionetc. (DAkkSakkredited)
  National and international research partner
• recycling of rare earth metals/permanent magnets
• additive manufacturing of metals
  Head: Prof. Dr.Carlo Burkhardt
• 4 national projects, 3 international multilateral (EU) projects (>30 M€ overall budget)

LMM Additive Manufacturing

Lithography-based Metal Manufacturing

• basedon theVat-PolymerizationPrinciple
• verygoodsurfacecharacteristics
• verygoodgeometricalprecision
• nothermal distortions
• materials: stainlesssteel, toolsteel, titanium, […]
• suitable also for non-weldable materials
• printing speed: max. 16 cm³/h
• suitable for:
• smalland very small parts(<30g)
• smalltomoderate quantities

LMM-Process

How it works

LMM-Process

Sintering

LMM-Process

Shrinkage

LMM-Process

Precision

• finished part tolerances up to ±0.5% of nominal dimension possible
• stair-step effect due to layer-by-layer production

LMM-Process

Surfaces

LMM-Process

Some parts

MetShape GmbH

• Start-up and spin-off of Pforzheim University as of 01.04.2019
• funded by the program “Young Innovators” of the Ministry of Science, Research and the Arts Baden-Württemberg
• specialized in additive component manufacturing using the Lithography-based Metal Manufacturing process (LMM) and related development services
• main focus:
  • conducting feasibility studies for components and materials
  • small scale productions
  • installationof process chains for in-house production

a speech by Christopher W Corti

Abstract

Platinum has only been known to Europe since the 16^th century. This was impure platinum which is found as grains of native metal in alluvial deposits, often associated with native gold. Such grains are mainly platinum alloyed with the other 5 platinum group metals and were exploited by pre-Colombian Indians of Ecuador and Colombia in NW South America.

In more recent times, the popular use of platinum in jewellery dates from the early 20^th century, often as a basis for diamond (and other precious gemstone) jewellery.  Its use in jewellery was restricted in the Second World War as it was considered a strategic industrial metal with limited availability. Thus, early jewellery alloys tended to be based on the existing industrial alloys and comparatively little development of specific jewellery alloys was carried out.  Its acceptance as a hallmarkable jewellery metal came much later in 1975 when, with a wider availability of the metal, platinum was promoted as a high value jewellery metal and platinum jewellery started to grow in popularity, mainly at 950 and 900 fineness qualities. Since that time there has been alloy development specifically for jewellery application and tailored to the requirements of different manufacturing technologies.

This presentation reviews the evolution of platinum alloys over the last century against the challenges – physical and metallurgical – presented in developing improved alloys for jewellery application.

INTRODUCTION

Platinum has only been known to Europe since the 16^th century with rumours of the existence of a white metal, platina, in central and south America that cannot be melted¹. This was impure platinum which is found as grains of native metal in alluvial deposits, often associated with native gold. Such grains are mainly platinum alloyed with the other 5 platinum group metals (PGMs – palladium, rhodium, ruthenium, osmium and iridium) – and were exploited by pre-Colombian Indians of Ecuador and Colombia in NW South America. Analysis of ancient trinkets indicates that iron and copper were also present as impurities¹.

JEWELLERY ALLOYS: 1920s to 1999

In more recent times, the popular use of platinum in jewellery dates from the late 19^th– early 20^th century, often as a basis for diamond (and other precious gems) jewellery. Smith, in his book published in 1933², notes its use in jewellery at 99.5% fineness with small additions of alloying metals to harden it, including Ir, Rh, Ru, Au, Ag and Cu. He also notes that the platinum standard (in the UK) is 950 fineness and is finding general acceptance.  The term ‘platinum’ is deemed to include iridium.  He further notes that much of the platinum in use in jewellery is alloyed with copper to improve hardness and colour. The use of platinum in jewellery was restricted in the Second World War as it was considered a strategic industrial metal with limited availability, which led to the development of white gold alloys as an alternative for jewellery. Thus, early jewellery alloys tended to be based on the existing industrial alloys and comparatively little development of specific jewellery alloys was carried out. These tended to be 90-95% platinum alloyed with other PGMs, usually iridium. These alloys have high melting temperatures, making manufacturing of jewellery, particularly investment (lost wax) casting, difficult and challenging for the jeweller used to gold and silver.

A further issue had been the lack of accurate analysis techniques. All this meant that its acceptance as a hallmarkable jewellery metal in the UK came much later in 1975³.  From this time, with its now much wider availability, platinum was promoted by the platinum producers as a rare, high value jewellery metal and platinum jewellery grew in popularity, mainly at 950 and 900 fineness qualities, in Japan, Europe and the USA, although some growth in demand began earlier in Japan in the 1960s for historical reasons linked to the ban on the import of gold until 1973.  This marketing and growth led to some alloy development such as the platinum-cobalt alloy for investment casting⁴ and the use of gallium additions to produce heat treatable alloys with higher strength and hardness⁵ as Normandeau has reported⁶. For example, one European platinum producer lists only 4 alloys for jewellery application in their catalogue dating to the late 1980s, all at 950 fineness, namely platinum – copper, platinum – cobalt, platinum -ruthenium and platinum-gallium-indium. The copper alloy is listed as a general purpose alloy and the cobalt alloy is listed as suitable for investment casting. Another European producer lists only 3 alloys at 950 fineness:  Pt-5Cu, Pt-5Co/Ni and Pt-5Ru.

Huckle of Johnson Matthey reported on the development of platinum alloys to overcome production problems at the 1996 Santa Fe Symposium⁷. He noted that platinum and its alloys had some different characteristics compared to gold and silver, notably weight, hardness and thermal conductivity and that its alloys have a high density, as well as high melting points. Its high surface resistance leads to clogging (galling) and high wear of saw blades, files and machine tools. He notes that, in Japan, Pt-Pd alloys are in common use, particularly Pt-10%Pd, whereas in Europe Pt-5% Cu is preferred but that it is not a good casting alloy whereas for casting application Pt-5%Co is finding success. In the USA, he notes Pt-10%Ir is commonly in use as an all-purpose alloy and that Pt-5%Ru is used where a hard, good machining alloy is needed. He also notes Pt-5% Co is finding growing use for casting applications in the USA.

Maerz (Platinum Guild International) also reviewed platinum jewellery alloys at the 1999 Santa Fe Symposium⁸ and this built on the information provided by Huckle. It sums up the alloys widely available and their application in jewellery at that time with some comment on the new alloys being introduced, Table2.

In this context, Maerz and Huckle noted that it is important to recognise the different marking standards of various countries at that time. Maerz noted that European countries generally allowed only 950 fineness alloys, with some allowing no negative tolerance (Austria, Ireland, Sweden, Norway, Finland, United Kingdom and Switzerland), some allowing a small negative tolerance (Denmark, Portugal and Italy) and others allowing iridium content to be counted as platinum within the 950 standard (Belgium, France, Italy, Greece, Netherlands and Spain). In Germany, he noted that several fineness standards and alloys were allowed, Table 1.

In the USA, he noted that the standard for jewellery to be marked as platinum was 950 fineness but that the minimum amount of platinum allowed was 500 parts per thousand with the rest of the alloy comprising 950 parts per thousand total platinum group metals (PGMs) with a zero tolerance. He also notes that 950,900 and 850 fineness standards are allowed in Japan.

With regard to actual alloy compositions, he notes that each alloy is made for specific manufacturing functions. Some alloys are preferred for tubing or machining and others for casting, for example, and there are differences in preference in different countries. Table 2 lists the alloys in common (or growing) usage around the world with their function and countries of major use.  He also lists separately a number of alloys that are specific to Japan

Maerz’s list did not record the platinum-5% copper alloy (except its use in Japan) which has been mentioned above as an alloy commonly used in Europe. Maerz does note that, in the USA, the most common alloys in use are 950 platinum with 5% cobalt or ruthenium and 900 platinum – 10% iridium alloy. However, in an updated later version of this paper⁹, the Pt-5Cu alloy is included.

In his book published in 1984, Savitskii¹⁰ notes only two 950 fineness alloys are in use in the old USSR – Pt-5 Ir in Russia and Pt-4.5 Pd – 0.5 Ir in East Germany (GDR).

TECHNICAL ASPECTS OF ALLOYS: 1920s to 1999

From the list of alloys summarised in Table 2, it is evident that at 950 and 900 fineness qualities, there is a broad range of alloys available to the jeweller, each suited to various manufacturing techniques. All have a good white colour, although some may benefit from rhodium plating, e.g. Pt-10% Pd alloy, to give a brighter, whiter colour. The main differences lie in their hardness (or strength) and melting ranges.

Battaini has examined the microstructure of several platinum alloys¹¹ and notes many alloys are single phase, as one might expect from examination of their phase diagrams, particularly at 950 and 900 fineness qualities.  Some alloy systems, however, show large areas of miscibility gaps at low temperatures, for example Pt-Au and Pt-Cu systems and this raises the possibility of age-hardening alloys by heat treatment.  Platinum-5% gold is an example here, Fig 1(a), where an aged hardness of HV300 can be attained, leading to better scratch and wear resistance, but I have not observed its use in as-cast Pt-Au rings^12,13, suggesting it is a treatment not in common use. Platinum- cobalt, Fig 1(b), forms an ordered intermetallic compound, Pt₃Co, that could also enable some hardening at 950 fineness.  The use of gallium also allows age hardening, as is evident from the phase diagram, Fig 2, as well as lowering melting ranges and its use forms the basis of several heat treatable alloys as noted earlier.

Clearly, some alloys are quite soft (hardness lies in range HV50-100), some have a moderate hardness (HV100-150) and others are quite hard (HV 150 – 350), the higher values usually when in the age-hardened condition. In a recent study by the author of customer complaints^12,13, it has been noted that use of soft alloys is a significant factor in platinum jewellery becoming deformed in shape and badly scratched when worn by consumers, particularly in as-cast gem-set rings and wedding bands.

Work around the turn of the 21^st century and summarised in recent reviews^14,15 has demonstrated that microalloying of pure platinum and its alloys with small additions of calcium and/or rare earth metals such as cerium, samarium and gadolinium, typically up to about 0.3%, can increase hardness substantially but such micro-alloys do not appear to have been commercialised by the jewellery industry, probably because they are not easily cast or recyclable.

The melting point of pure platinum is 1769°C, considerably higher than gold (1064°C) and silver (961°C). Its alloys tend to have similarly high melting ranges, as shown in Table 3, although the gallium-containing alloys do have a significantly reduced melting range. Thus, melting and casting platinum alloys requires good furnace equipment capable of attaining melt temperatures some 100°C above the liquidus temperature of the alloy for investment casting. Induction melting is preferred. Melting by gas torch is not easy, although a propane or hydrogen-oxygen torch can be used by bench jewellers.  However, in general, working of platinum alloys is not a problem, although polishing requires skill and effort to obtain a good quality polish. Machining of platinum also requires skill to obtain a good smooth finish, requiring special tool materials and different tool geometries¹⁶, as platinum tends to gall (adhere) on the tool. The low thermal diffusivity of platinum alloys makes welding easier, particularly laser welding¹⁸ compared to gold and silver alloys.

The major manufacturing problem has been with investment casting.  The high melting and casting temperatures require use of special phosphate bonded investment mould materials¹⁹ and the poor melt fluidity requires use of centrifugal casting machines²⁰ to obtain good mould fill rather than the modern gravity machines commonly used for gold and silver. The new generation of tilt casting machines are also suitable. The chief problem with platinum casting is getting defect-free castings^7,20,21 and there have been several investigations on the relative merits of different alloys^4,22-24, looking particularly at surface quality, form-filling and gas and shrinkage porosity. The general findings from these studies show the Pt-5%Co alloy to be the best of current alloys but still not ideal.

JEWELLERY ALLOYS: 2000 to the Present

There have been several studies to develop improved platinum jewellery alloys in the last two decades. These have focussed on either stronger (harder) alloys or improved investment casting

alloys, although alloys suitable for additive manufacturing (3D printing) technology have also been of interest.

A] Stronger, harder alloys

The resistance of jewellery to abrasion and knocks – wear and scratch resistance – depends to a large extent on the hardness of the alloy. As noted earlier, a study of customer complaints showed platinum rings and wedding bands to be particularly prone to deformation of shape (misshapen) and to heavy wear (scratches and dents) during customer service (i.e. whilst being worn), when made in soft – moderately hard alloys. Hard alloys tend to be difficult to work in manufacture, especially to set gems in mounts, and so it is advantageous if an alloy is relatively soft whilst being manufactured into a piece of jewellery but can be subsequently hardened to improve its durability whilst being worn by the customer. This can be achieved by age hardening of suitable alloys after manufacture, a treatment involving the precipitation of a dense dispersion of fine particles of a second phase within the matrix grains.

For platinum, it has been noted that some current alloys are age-hardenable and alloys containing gallium have been developed specifically for this purpose. The first was the Pt-3% Ga-1.5% In alloy developed by Johnson Matthey⁵ and others have also followed such as the HTA alloy⁶ developed by Imperial Smelting and the ‘S’ alloys developed by S Kretchmer and discussed by Maerz⁸. Weisner, in a paper²⁵ presented in 1999, discusses heat treatable alloys and notes earlier work at Degussa, C Hafner, Johnson Matthey (Pt-Ga-In) and S Kretchmer (Pt-Ga-Pd) to develop heat treatable 950 platinum alloys. He notes that all are ternary alloys, many with melting ranges much lower than the conventional binary alloys, suggesting they all contain gallium and/or indium additions. Such alloys are useful for their spring properties in springs and clasps, for example.

Research²⁶ carried out at Mintek, South Africa in 2005 has examined potential platinum alloy systems with additions of 7% or less to identify suitable binary alloy systems that can be substantially age-hardened. Over 20 alloying metals were studied in the preliminary trials at levels of addition of 2 & 4 % and those showing promise were also studied at the 3% addition level. From this work, alloys with additions of Ti, Zr, Sn, Ga, Ge, Mg, In and V were studied in more depth. From this, along with consideration of other aspects, it was concluded that the best alloy was a Pt-2% Ti alloy which had as cast and annealed hardnesses sufficiently low to be easily worked and formed but with subsequent heat treatment, the hardness value could be increased by about HV90. Interestingly, there are parallels here with the development of 990Gold (Au-1%Ti) alloy²⁷. The Mintek work does not appear to have been further developed into a commercial alloy, possibly because it does not show much advantage over the existing commercial gallium-containing alloys.

More recently, a harder general purpose alloy, TruPlat™, has been introduced to the market in the USA by Hoover & Strong. It is a 950Pt-Ru-Ga alloy that is not age-hardenable. It has a higher work hardening rate compared to 950Pt-Ru, with an annealed hardness of HV180.

B] Improved casting alloys

The motivation here is to develop alloys less prone to casting defects, particularly casting porosity.  Use of alloys with lower melting ranges to inhibit mould reaction is desirable too. Work carried out by Fryé at Techform and Klotz and co-workers at FEM ^{23,24 28-30, 32} on platinum cast in shell and conventional moulds has focussed on which alloys are best in terms of casting porosity formation, form-filling and surface quality and establishing the mechanical properties of cast alloys. The use of computer simulation of the casting process has also assisted in optimising process parameters in casting. Fryé has also shown the benefits of a Hot Isostatic Pressing (HIP) treatment post casting in removing porosity from castings and improving mechanical properties. What is particularly noticeable is the growing number of new platinum casting alloys that feature in these studies.  This alloy development started a little earlier in 1997.

In a paper³⁴ presented at the 1997 Platinum Day symposium in New York, Lanam, Pozarnik and Volpe reported on a new investment casting alloy, 950 Pt-Cu-Co, developed at Engelhard, that combines the good properties of Pt-5Co and Pt-5Cu and reduces the issue of magnetism in Pt-Co alloy. It’s as-cast hardness is about HV119, somewhat lower than Pt-5Co. Porosity was still present and it had a tendency to form a surface oxide on heating.

Another alloy development was presented by Normandeau in 2000³⁵ in which he reported on a new 950 platinum Hard Casting Alloy (HCA) with an as-cast hardness of HV 160-170, much higher than Pt-5Co alloy. Little detail is given on the composition but the discussion in the paper points to it being a 950Pt-Ga-Ir alloy, since he provides data on the Ga:Ir ratio and it’s effect on hardness.

A further alloy development was presented by Grice & Cart in 2002³⁶ where the development of a 950 Pt-Au-X alloy, PlatOro™, is reported as an alternative to Pt-5Co. This has an as-cast hardness of HV125, a little softer than Pt-5Co alloy but is non-magnetic and has lower melting range of 1590° – 1629°C. This does not appear to be the Pt-Au-In alloy examined by Fryé & Klotz³⁰ and Maerz and Laag³³, Table 4, since the melting ranges and hardness values are different.  Grice has since reported³⁷ that the PlatOro™ alloy is actually a Pt-Au-Cu alloy but is no longer commercially produced.

Fryé and Fischer-Buehner in their study reported in 2011²⁴ recognised the inadequacies of the existing commercial casting alloys and widened their search to include 3 newer versions that contained undisclosed elements, which they designated as hard alloys (HV175 or greater). These are included in the table of alloys reported in Table 4. The platinum-cobalt- X hard alloy with unknown additions appeared to show some promise. The Pt-Ru-X alloy is now known to be the Pt-Ru-Ga alloy from Hoover & Strong³⁷ and the Pt-Co-X alloy is a Pt-Co-In alloy from Legor³⁸ and is harder and non-magnetic compared to Pt-Co.

In 2014, Klotz et al at FEM utilised computer simulation of casting and thermodynamic calculations to optimise the process parameters of casting Pt-5Ru and Pt-5Co alloys²⁹ and was significant in that ternary alloys of 950 platinum-cobalt-ruthenium alloys were explored. Improved form-filling and surface quality resulted from additions of Co to Pt-Ru alloys, the optimum amount depending on casting technique – centrifugal or tilt casting.

Maerz and Laag³³ studied six alloys in their 2016 study, Table 4, which used tilt casting (as opposed to centrifugal casting) in their trials. Two contained gallium or indium and these alloys showed higher as-cast hardness and were rated high in terms of castability. Each alloy had different strengths and weaknesses and the authors concluded that no alloy was perfect but that progress was being made. It is noted that C Hafner patented an alloy, 950 Pt-Au-In in 2013, with the use of Ir or Ru as grain refiners³⁹, which is probably the alloy referred to in Table 4

The largest range of alloys was studied by Fryé and Klotz, Table 4, who also measured mechanical properties and wear resistance of castings³⁰. They warned against use of soft alloys in cast jewellery and noted pronounced micro-segregation in Ga- and In-containing alloys which increased micro shrinkage porosity. Hot isostatic pressing treatment (HIPing) after casting eliminated porosity and restored ductility. They also noted wear was related to hardness, harder alloys wearing less.

It is clear from the foregoing that no new alloy completely met the desired casting requirements, although a database of mechanical properties of many of the casting alloys was established by Klotz and Fryé for alloys in the as-cast and in the HIPed condition³². This database has data on 13 compositions at 950 fineness and 2 at 900 fineness. As well as the conventional compositions described in Tables 2 and 4, it also includes some newer ternary/quaternary compositions, as shown in Table 5, which only lists the hardness values; perhaps, it also clarifies some of the unknown compositions documented in Table 4.

A more fundamental approach to improved casting alloy design³⁹ has been undertaken recently by Professor Glatzel and his co-workers at the University of Bayreuth and Richemont International.  They looked to develop an improved casting alloy of 950 fineness with the following requirements:

• Low casting temperature
• Small melting range
• Microstructure that is homogenous, fine-grained (100 – 150 µm) and with low porosity
• Hardness in range Hv 155-170 for wear resistance and good ductility (>30%)
• Good reflectance with a bright surface
• Alloying elements that are biocompatible and recyclable

Their benchmark alloy was the 95Pt-1.8Cu-2.9Ga which is a recent alloy development (see Tables 4 & 5). Excluding allergenic, radioactive and toxic elements, 25 possible alloying elements were selected and ranked according to a Suitability Index which comprised 4 characteristics: maximum solubility in platinum (C_max), hardness Index (H_i), melting interval index (M_ii) and liquidus temperature change index (T_lci). From these, a first iteration of 5 alloys were selected for testing and following this, a second set of 5 alloys were selected for testing. Casting was performed in a tilt casting machine. These alloys contained up to 5 alloying elements from a list including Al, Au, Cu, Cr, Fe, Ir, Mn, Pd, Rh and V. From these 10 alloys, two in the second iteration were found to be the most promising, Table 6. It is very evident that these compositions are radically different from those listed in Tables 4 and 5.  They have a hardness of HV 164 (A2) & 165 (B2) respectively compared to HV 225 for the benchmark Pt-Cu-Ga alloy. It will be interesting to see if these or similar alloys are developed to commercial status and find a niche amongst the current alloys. With the base metal alloying elements including iron and manganese, it is possible there may be tarnishing issues with such alloys, if we compare the experiences in developing alternative white gold compositions.

C] Alloys for Additive Manufacturing (3D Printing)

The development of Additive Manufacturing (3D printing) of jewellery has attracted much interest in the industry in recent years and considerable R & D has been carried out on developing machine technology, build techniques and suitable alloys. The technology involves selective laser melting (SLM) of successive layers of alloy powders, and it has become evident that such powders need to be tailored in composition to suit the process. Alloying additions of high vapour pressure metals are not desirable, for example.  In the field of carat golds, it is also important to reduce reflectivity and thermal conductivity/diffusivity to better absorb energy and inhibit heat loss through the metal, thus enhancing consolidation of the powders during laser melting. Examples of modifying carat gold alloy compositions have been discussed⁴⁰.  Regarding platinum alloys, these tend to have considerably lower thermal conductivities as has been discussed by Wright in terms of laser welding¹⁸ and Zito in terms of 3D printing of jewellery⁴¹ Work at Progold Spa on laser selective melting of 950 fineness platinum jewellery has been reported by Zito and his co-workers^41-44. In his 2014 paper⁴¹, Zito used an unspecified 950 Pt alloy powder whilst in his 2015 paper⁴³, Zito used a 950 platinum alloy powder ‘with alloying additions slightly different from the cobalt-containing alloy used in the preceding work’ but gives no further details other than to say it was not doped with semiconductor elements to reduce thermal conductivity (as was done with the carat gold alloys in his work). In the 2018 paper, in which jewellery made by SLM is compared to the same pieces made by investment casting⁴⁴, Zito notes the items produced by casting and by SLM were made in the same 950 Pt-Cu-Ga-In alloy but gives no details on actual composition. This is different from the casting alloys discussed in the earlier section, in that it contains indium as well as copper and gallium.

Thus, it appears that there is little need to develop special alloy compositions suited to 3D printing technology; the conventional alloys are acceptable and do not appear to pose any major problems.

D] Other Alloys

To conclude this paper, I note there are other recent alloy developments that appear in the patent and other literature that do not fit into the 3 preceding categories. For example, European Patent applications from Heimerle and Meule⁴⁵ describe alloys that have optimised processing properties at 950 and lower finenesses based on Pt-W-Cu –(Ru/Rh/Ir) and described as having high hardness and abrasion resistance. The Ru/Rh/Ir additions act as grain refiners.

Another patent from the watchmaker, Omega SA⁴⁶, concerns 950 platinum alloys that are cobalt- and nickel-free, based on Pt-Ir-Au-Ge- (Ru/Rh/ Pd/Sn/Ga/Re) that have mechanical properties that meet the criteria for watchmaking whilst having the colour and luminosity of Pt-Ir alloys.

CONCLUSIONS

1. There has been an evolution of – and growth in – platinum alloy compositions for jewellery application since the 1920s, with a focus on developing alloys suited to the manufacturing technologies in current use. Until the advent of the 21^st century, most platinum alloys for jewellery were based on the existing industrial alloys with the platinum -iridium alloys favoured in the early part of the 20^th century.
2. There is now a wide range of alloys available at 950 and 900 fineness levels with a spectrum of properties. Of note has been the development of heat treatable alloys containing gallium.
3. The investment casting of platinum alloys remains a major issue in terms of surface quality and defect formation, particularly gas and shrinkage porosity. The use of hot isostatic pressing post casting removes porosity and improves mechanical properties. As yet, there is no ideal casting alloy to replace the universally accepted Pt-5Co alloy..
4. There has been a major evolution in platinum alloys, particularly for investment (lost wax) casting application, in the last two decades (21^st century). A recent substantial, structured alloy development approach has produced some significantly different casting alloys containing up to 5 alloying metals It remains to be seen if these prove to be superior.
5. The new manufacturing technology of additive manufacturing (3D printing) does not appear to require special alloy compositions.

ACKNOWLEDGEMENTS

I would like to thank Massimo Poliero and his staff at Legor Srl for inviting me to present at the Jewellery Technology Forum once again.  It is always a pleasure to present at this important international technology conference.

Thanks are also due to many friends and companies in the industry for information and allowing use of pictures and tables; these include Johnson Matthey, Legor,FEM, Progold, Platinum Guild International, Hoover and Strong and Techform.

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Note: Papers published in Platinum Metals Review/Johnson Matthey Technology Review can be downloaded free from the archive at https://www.technology.matthey.com/ . Many papers from the various Santa Fe Symposia can be downloaded free from the Santa Fe Symposium website archive at www.santafesymposium.org . Papers from Gold Bulletin can be downloaded from the Springer/Gold Bulletin website at https://link.springer.com/journal/13404/volumes-and-issues