Platinum tungsten alloy
The platinum alloy is composed of platinum base and tungsten. It forms a simple peritectic phase diagram, and the peritectic reaction temperature is about 2460 ℃. With the increase of tungsten content, the strength of Pt-W alloy increases significantly. However, only the single-phase solid solution containing less than 10% tungsten can be processed and has practical value. The physical and mechanical properties of platinum rich platinum tungsten alloys.
Pt-W alloy is an excellent strain material for precious metals. The typical alloys are PtW8 and PtW9.5, which have high tensile strength, resistivity and resistance strain sensitivity coefficient, low resistance temperature coefficient and excellent oxidation resistance. The resistance strain gauge made of PtW9.5 strain line has been successfully tested on the rotating parts of aeroengine. The development of China's aviation industry has promoted the development and application of platinum tungsten alloys. PtW8, PtW8.5 and PtW9 alloys have been successfully trial produced, and new high temperature resistance strain alloys Pt-W-Re-Ni-Cr-Y have been invented. Platinum tungsten strain wire is used to make 700 ℃ static resistance strain gauge, and platinum tungsten ultra-fine wire (0.008mm) is used for relaxation type micro pressure sensor. The strongly hardened ptw4 alloy is used as spark plug electrode and grid of radar power tube. Ptw8 alloy used as potentiometer winding is very wear-resistant and low noise.
