An electrical resistance study of the precipitation reaction in a gold-platinum-iron alloy

✍ Scribed by Sims, Julius R. ;Blumenthal, Robert N. ;O'Brien, William J.

• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 549 KB
• Volume: 7
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.820070603

✦ Synopsis

Abstract

The aging reaction of a 90 wt‐% gold, 10 wt‐% platinum alloy with nominal iron concentrations of 0.04, 0.08, and 0.16 wt‐% iron has been studied using electrical resistance measurements. The electrical resistance was measured as a function of temperature from 300 to 750°C. A decrease in electrical resistance was observed occurring at 350 to 450°C, when heating the solution treated and water quenched specimens containing iron. Subsequent heating and cooling curves follow the gold‐platinum standard. Isothermal electrical resistance measurements were made as a function of time. The data from the specimen containing a nominal iron concentration of 0.16 wt‐% iron was analyzed using the Johnson‐Mehl equation. The shape parameter n was found to vary as a function of aging temperature from n = 0.6 to n = 1. These results have been rationalized in terms of a model involving precipitation of FePt~3~ at dislocations (400°C) and FePt~3~ in the shape of a rod at 500°C.