platinarhodiumkatalysatorer

Platinarhodium refers to a binary alloy composed primarily of platinum with rhodium as a minor constituent. In common usage the term denotes Pt–Rh alloys, though it can also describe rhodium plating on platinum or white gold used to enhance appearance and durability.

Composition and properties: Rhodium content in Pt–Rh alloys typically ranges from a few percent to about 20%, depending on the intended use. Platinum and rhodium form a solid solution with a high melting point, and the resulting alloys exhibit improved hardness and creep resistance relative to pure platinum. They maintain excellent resistance to oxidation and corrosion at elevated temperatures, contributing to stability in demanding environments. The microstructure is typically a fine, single-phase face-centered cubic material after proper processing.

Applications: Pt–Rh alloys are widely used in catalytic converters, where rhodium promotes reduction of NOx while platinum assists oxidation of CO and hydrocarbons. They are also used in high-temperature thermocouples, notably Type S (Pt–10Rh vs Pt) and Type R (Pt–13Rh vs Pt), for accurate measurements up to high temperatures. In jewelry and decorative plating, rhodium plating on platinum or white gold enhances brightness, hardness, and tarnish resistance. Pt–Rh compounds and components are also found in laboratory crucibles and electrical contacts that require high-temperature stability and chemical inertness.

Production and processing: Pt–Rh alloys are produced by melting and alloying platinum with rhodium under controlled conditions, followed by casting, annealing, and possible cold-work processing to achieve the desired mechanical properties and microstructure. The exact composition is selected to balance catalytic activity, mechanical strength, and high-temperature performance.

Safety and handling: As with other platinum-group metals, Pt and Rh are relatively inert but can pose risks if inhaled as oxide fumes or finely divided powders. Handling should follow standard industrial hygiene practices and relevant regulations.