A series of iterative wear and corrosion tests were conducted on two 950 platinum alloys, two 585 white gold alloys, and two 750 white gold alloys. Testing followed standardized industrial procedures in order to provide comparable and reproducible conditions. Wear testing comprised a sequence including abrasion testing, corrosion testing, and polish testing. Mass loss was recorded after each test cycle. Five complete test cycles were followed by two long-term polish tests. The total testing time was ca. 250h. A pronounced difference in the mass and volume loss between the platinum and the gold alloys was observed. The absolute volume loss per surface area of the platinum alloys was a factor of two to three times lower than that of the gold alloys. The highest volume loss was observed for 750 AuPd, followed by 585 AuPd, 585 AuNi and 750 AuNi with the latter three showing similar wear behaviours. The mass loss increased linearly with testing time. No measurable mass loss was observed by corrosion testing in our limited duration test cycle and the only alloy exhibiting significant corrosion was 585 AuNi. Hardness of the alloys was determined by Vickers microhardness testing at a 100g load. Notably, higher hardness levels were not found to be an indicator for low mass or volume loss.
Phase Diagram of Nanoparticles of Palladium-Platinum Alloys
