Platinum Metals Review - Volume 56, Issue 3, 2012

In this paper, applications of the platinum group metal (pgm)-based diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) technologies for John Deere Interim Tier 4 non-road machines are presented. The same criteria apply to EU Stage III B regulations. The design and performance of engine aftertreatment systems are discussed in detail, and a few key performance characteristics of DOC-DPF systems are addressed. Significant passive soot oxidation was observed. Model based controls were found to properly account for passive regenerations of the DPF and could be used to schedule active regenerations automatically. Active regenerations were transparent to operators. Tight DPF inlet temperature control and engine exhaust temperature management were found to be key for successful active DPF regenerations. The average fuel consumption for active regenerations was estimated by a simple energy balance model. The emission performance of a DOC-DPF system under normal and active regenerations is summarised, and ash accumulation and DPF pressure drop impact are analysed.

There is much interest in developing new casting alloys and techniques for platinum. Despite numerous advances in casting equipment and technology, there are still many areas to improve upon which can reduce production costs and result in a sturdier product. This review examines the casting behaviours of 900 and 950 platinum alloys with additions to increase the hardness. The main aim of this study was to discover the solidification patterns of platinum alloys from molten to the solid state, with characteristics assessed including shrinkage porosity, gas porosity and form filling. In addition, alloy hardness levels and the effects of thermal post-processing of castings were explored.

Ten application areas and ten properties of platinum (or its alloys) are selected here to represent a “platinum decathlon”. Platinum has a unique combination of properties which make it eminently suitable for many applications from jewellery to anticancer drugs, from high-temperature engineering to a range of catalytic applications. The 18th century French chemist Antoine Baumé foresaw the desirability of platinum’s use in industry and its use today in many essential areas bears this out.

The crystallographic properties of palladium at temperatures from absolute zero to the freezing point are assessed following a review of the literature published between 1901 to date. However values above 1100 K are considered to be highly tentative since they are based on only one set of measurements. Selected values of the thermal expansion coefficient and measurements of length change due to thermal expansion have been used to calculate the variation with temperature of the lattice parameter, interatomic distance, atomic and molar volumes and density. The data is presented in the form of Equations and in Tables whilst a comparison between selected and experimental values is shown in the Figures.