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Platinum as a Metallic Material

Processing Platinum and Alloys (forming, welding)

Fig.1
Rolling
© Heraeus

Rolling a platinum sheet

Physically or chemically pure platinum is very soft and ductile. The cast ingots can therefore be readily formed by cold rolling and other conventional forming processes. To achieve the optimum surface quality of the semi-finished products, it is advantageous to skim machine the surface of the cast ingot, e.g. by planing.

Hot working

As the alloying elements rhodium and iridium increase the mechanical strength of platinum, the forming of platinum-rhodium and platinum-iridium alloys is – depending on the rhodium or iridium content – somewhat more difficult than it is the case for pure platinum. Hot working by forging or rolling can be advantageous both for the microstructural homogeneity and for subsequent cold working to semifinished products. Because the work hardening causes an increase in strength during cold forming the alloys, annealing treatments are necessary which are normally carried out at 900-1,000 °C. As the strength and the work hardening increase with increasing alloy content, the frequency and the temperature and duration of the annealing treatments must be adapted to meet the particular alloy composition.

Finished products are manufactured from the semifinished products by means of all conventional forming processes, e.g. spinning, deep drawing, tube and wire drawing.

Welding

Fig.2
TIG welding
© Heraeus

TIG welding a component made of PtRh90/10 alloy for use in the glass industry

Furthermore, platinum materials can be readily welded. The most commonly used method is the tungsten-inert gas technique (TIG). Other methods, such as laser, electron beam and plasma welding can also be used without difficulty.

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