Deformation and fracture behaviour of cold drawing iridium wire under tension at room temperature is examined. High purity polycrystalline iridium was manufactured using pyrometallurgical technology. During the initial stage of cold rolling, iridium wire has its usual grain structure and exhibits brittle deformation behaviour: poor plasticity and brittle transgranular fracture (BTF). However, the wire begins demonstrating high plasticity including necking in spite of the brittle fracture mode when the lamellar structure has been formed in iridium during cold drawing.

Clustered together in the centre of the Periodic Table lie six remarkable elements, six metals without which the world would be a completely different place. Think about the food you eat, your computer, your car, your mobile phone or even the clothes you wear. At some stage during their production one or more of these six rare metals has been utilised, whether as a catalyst or perhaps in...

Platinum-based alloys are being developed for high-temperature applications with the aim of replacing some of the currently used nickel-based superalloys (NBSAs) and benchmark alloy, PM2000. The platinum-based superalloys have a similar structure to the NBSAs and can potentially be used at higher temperatures and in more aggressive environments because platinum is more chemically inert and has a higher melting point. In this paper, the recent progress in research and development of platinum-based superalloys is overviewed. Firstly, the composition optimisation and structural design of platinum-base superalloys are introduced. The structural characteristics, mechanical properties, oxidation resistance and corrosion behaviour of platinum-aluminium ternary, quaternary and multiple superalloys are summarised. Finally, directions for further research and application of platinum-based superalloys are analysed and prospected.

Here, we report the frequency dependent ultrasonic attenuation of monometallic gold and bimetallic gold/platinum based aqueous nanofluids (NFs). The as-synthesised bimetallic NFs (BMNFs) revealed less resistance to ultrasonic waves compared to the monometallic NFs. Thermal conductivity of both NFs taken at different concentrations revealed substantial conductivity improvement when compared to the base fluid, although gold/platinum showed lesser improvement compared to gold. Characterisation of the as-synthesised nanoparticles (NPs) and fluids was carried out with X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The distinct two-phase bimetallic nature of gold/platinum, its two plasmonic band optical absorption features and the spherical morphology of the particles were shown. The findings were correlated with the observed thermal and ultrasonic behaviour and proper rationalisation is provided. It was revealed that the comparatively lesser thermal conductivity of gold/platinum had direct implication on its attenuation property. The findings could have important repercussions in both industrial applications and in the mechanistic approach towards the field of ultrasonic attenuation in NFs.

Ruthenium tablets with mean grain size of ~4–5 μm were prepared by vacuum hot pressing (VHP), and tablets with maximum density of 12.2 g cm^–3 were obtained with sintering time of 2 h. X-ray diffraction (XRD) revealed that there was a texture change with sintering time. The microstructure of the ruthenium tablets was observed by electron backscatter diffraction (EBSD) and field emission scanning electron microscopy (FSEM). The microstructure evolution of ruthenium with sintering time is discussed.

It is known that platinum-rhodium thermocouples exhibit mass loss when in the presence of oxygen at high temperatures due to the formation of volatile oxides of platinum and rhodium. The mass losses of platinum, Pt-6%Rh and Pt-30%Rh wires, commonly used for thermocouples, were considered in this paper to characterise the mass loss of wires of the three compositions due to formation and evaporation of the oxides PtO₂ and RhO₂ under the conditions that would be seen by thermocouples used at high temperature. For the tests, the wires were placed in thin alumina tubes to emulate the thermocouple format, and the measurements were performed in air at a temperature of 1324°C, i.e. with oxygen partial pressure of 21.3 kPa. It was found that the mass loss of the three wires increases linearly with elapsed time, consistent with other investigations, up to an elapsed time of about 150 h, but after that, a marked acceleration of the mass loss is observed. Remarkably, previous high precision studies have shown that a crossover after about 150 h at 1324°C is also observed in the thermoelectric drift of a wide range of platinum-rhodium thermocouples, and the current results are compared with those studies. The mass loss was greatest for Pt-30%Rh, followed by Pt6%Rh, then platinum.

Johnson Matthey is keen to encourage research into future applications of platinum group metals (pgms). As a global leader in sustainable technologies, our focus is on clean air, clean energy, healthcare and the efficient use of the planet’s natural resources – and on the fundamental properties of pgms on which these applications depend. Johnson Matthey’s commitment to progress in platinum...

Introduction Platinum group metals (pgms) have widespread applications as functional materials in many different industries. The applications range from catalytic surfaces or particles, sensors, biomedical imaging or drug delivery systems and thermocouples up to jewellery items that we use for special moments of our life. The pgms are used as solid bulk materials, powders, thin films,...

An optimal platinum alloy for precision casting was developed by taking 25 possible alloying elements into consideration. In order to rank these elements an equation was designed. The ranking allowed five promising alloy compositions to be identified. From these five alloys arc melted buttons were produced and tested for homogeneity and hardness to ensure their suitability as jewellery alloys. A pyrometer was used to measure solidus temperatures. In a second iteration, the five alloys were further improved and the most promising alloys were cast and compared to a commonly used jewellery alloy: platinum-copper-gallium (PtCuGa). The comparison was based on the melting interval and on microstructural investigations, carried out by scanning electron and optical microscopy, while mechanical properties were determined by tensile testing. Additionally, optical properties such as reflectivity and colour were investigated. After the second iteration two very promising compositions were identified: PtCuFeMnCr and PtCuFePdVY.

This review briefly describes the vacuum electrostatic levitation furnace developed by JAXA and the associated non-contact techniques used to measure the density, the surface tension and the viscosity of materials. The paper then presents a summary of the data taken with this facility in the equilibrium liquid and non-equilibrium liquid phases for the six platinum group metals (pgms): platinum, palladium, rhodium, iridium, ruthenium and osmium over wide temperature ranges that include undercooled and superheated phases. The presented data (density, surface tension and viscosity of Pt, Rh, Ir, Ru and Os and density of Pd) are compared with literature values.

The 28th annual Santa Fe Symposium® was held from 18th–21st May 2014 in Albuquerque, New Mexico, USA, and attracted another large attendance of delegates from 15 countries worldwide, representing a good cross-section of those involved in jewellery manufacturing from mass manufacture to specialised craft operations. In general, many were finding the market is tougher now than a few years...

Platinum-20% rhodium strengthened by oxides of zirconium and yttrium were prepared by solidification of platinum-rhodium-(zirconium)-yttrium powder which had been internally oxidised. After forging, rolling and annealing, 1 mm plates were obtained. Then the plates were mechanically ground to 50–70 μm from rolling-normal direction, followed by argon ion milling until a hole appeared on the centre of the foil to obtain samples which were characterised by transmission electron microscopy (TEM), combined with thermodynamic analysis. The existence of spherical ZrO₂ and Y₂O₃ particles was verified with platinum and rhodium present as pure metals at the same time. It was found that the deformation behaviour of ZrO₂ and Y₂O₃ particles was quite different during processing, where the former basically maintain their spherical shape and were bonded tightly to matrix, while the latter were compressed along normal direction and form two cracks on both sides of Y₂O₃ particles along the rolling direction. The differences in hardness and interface bonding properties of these two types of particles are supposed to be the main causes of different deformation behaviour during hot forging and cold rolling.

The use of various sintering technologies, allied to suitable powder metallurgy, has long been the subject of discussion within the global jewellery manufacturing community. This exciting, once theoretical and experimental technology is now undoubtedly a practical application suitable for the jewellery industry. All parts of the jewellery industry supply and value chains, and especially design and manufacturing, now need to become aware very quickly of just how unsettling and disruptive this technology introduction has the potential to become. This paper will offer various viewpoints that consider not only the technology and its application to jewellery manufacture but will also consider the new design potentials of the technology to the jewellery industry. It will also briefly consider how that design potential is being taught to future generations of jewellery designers at the Birmingham School of Jewellery. We shall also discuss in some detail the economics of and potential for new and different business models that this technological paradigm might offer the jewellery industry.

In this paper, changes in the mechanical properties of Pd-5Ni alloy are analysed after recrystallisation annealing in order to determine the optimal conditions for a thermomechanical processing regime for this alloy. The temperature and annealing time were varied and the resulting changes in hardness, tensile strength, relative elongation and proof strength were monitored. By using the simplex-lattice method and analysing experimental data, a fourth degree mathematical model-regression polynomial was defined and isolines of changes in the mechanical properties of the investigated alloys were designed depending on the conditions of heat treatment after rolling.

The changes in phase state, electrical properties and microhardness of copper-55 at% palladium alloy samples with different initial states (as-quenched and deformed via severe plastic deformation (SPD)) were studied during isothermal annealing. Ordered B2-phase formation in the disordered (A1) matrix was found to occur at a significantly higher temperature than is indicated in the generally accepted phase diagram of the Cu-Pd system. Corresponding electrical resistivity is also lower than reported elsewhere for alloys of similar compositions, at ρ = (27.67 ± 0.04) × 10^–8 Ωm, making this the lowest resistivity yet reported for a Cu-Pd alloy with 55 at% Pd.

Electrical resistivity values for both the solid and liquid phases of the platinum group metals (pgms) rhodium and iridium are evaluated. In particular improved values are obtained for the liquid phases of these metals.

In the 2014 review (1) discovery circumstances for 85Ru and 86Ru were referenced only in the form of a preprint but have now been reported in the open literature (2). For the most recently discovered isotopes the discovery years for both 128Rh and 90Pd are the manuscript dates of the given references whilst for 125Ru, 130Pd and 131Pd the common discovery year corresponds to the original...

In the 2012 review (1) the isotope 209Pt was included based on a claim to its discovery by Kurcewiz et al. which was reported in a preprint (2). However when the actual paper was published (3) it was considered that the evidence for 209Pt was unsatisfactory and it was no longer included. Therefore the number of known isotopes for platinum has been amended in Table I. In addition one...

This paper provides a database of mechanical properties for most of the commercially available platinum alloys currently in use for jewellery purposes. The alloys were tested for mechanical properties through tensile and microhardness testing in the as-cast and hot isostatically pressed conditions. Microstructural characterisations were performed using scanning electron microscopy (SEM).

Platinum has only been known to Europe since the 16th century. This was impure platinum, found as grains of native metal in alluvial deposits and comprising mainly platinum alloyed with the other five platinum group metals. They were exploited by pre-Colombian native populations of Ecuador and Colombia. In more recent times, the use of platinum in jewellery dates from the late 19th or early 20th centuries, often as a basis for diamond (and other precious gemstone) jewellery. 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 in 1975 when, with wider availability of the metal, platinum was promoted as a high-value jewellery metal. 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 review examines the evolution of platinum jewellery alloys over the past century against the challenges presented in developing improved alloys for jewellery application. There has been a substantial increase in alloy development over the past 30 years, particularly focused on improved investment (lost wax) casting alloys as well as better mechanical properties.