Platinum Metals Review - Volume 55, Issue 1, 2011

Palladium-based alloys with yttrium, copper, ruthenium or indium additions were investigated. Their specific hydrogen permeability, strength, linear thermal expansion in hydrogen and corrosion resistance in a number of gas media were determined. This allowed effective membrane elements to be developed using membranes made from these alloys, which are used for the separation of high purity hydrogen from hydrogen-containing gas mixtures. Membrane elements with 93.5 wt% palladium-6 wt% indium-0.5 wt% ruthenium alloy membranes were developed by the authors’ research group, and their technical characteristics are described.

Platinum is a challenging material for casters because of its physical properties, which result in possible crucible and flask reactions during melting and casting, high shrinkage porosity and difficulties in filling of filigree items. This paper summarises the results of a collaborative research effort by several industrial partners and FEM on the influence of casting process parameters. Two common platinum jewellery alloys (platinum with 5 wt% cobalt and platinum with 5 wt% ruthenium) and four different investment materials were used for casting experiments with variation of atmosphere, casting and flask temperature, tree design and centrifugal machine parameters. Detailed sample investigation found shrinkage porosity and surface defects to be the main problems. Optimised process parameters for heavy and filigree items were identified. Future research on platinum casting should focus on casting simulation in order to reduce experimental effort and costs.

Throughout his long and distinguished career with the Ford Motor Company Haren Gandhi was concerned with controlling tailpipe pollutants from cars, and through his work this article reviews the huge amount of progress made during his four-decade career. His early work with gasoline engines embraced all of the major developments ranging from the first platinum-based oxidation catalysts through nitrogen oxides (NOx) reduction using platinum-rhodium catalysts and the later introduction of palladium into three-way catalysts (TWCs) via ‘trimetal’, palladium-rhodium and palladium-only formulations. Gandhi’s other work included the interactions of poisons with catalysts as part of maintaining their in-use performance, the potential for using ruthenium in NOx control in gasoline TWCs and NOx adsorbing catalysts (NACs) for lean-burn engines, and the use of zeolite-based selective catalytic reduction (SCR) catalysts for effective diesel engine NOx control. Gandhi received many awards and honours in recognition of his technical achievements and a selection is mentioned here. Haren Gandhi is remembered with tremendous fondness and respect throughout the automotive industry concerned with exhaust gas emissions control and his technical contributions towards improving the quality of the air we breathe will continue to benefit us all.