中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 15 No. 3 June 2005 |
ZHAI Guang-ping(翟廣平)1, NIU Yan(牛 焱)2
（1. Department of Chemistry, Shenyang Normal University, Shenyang 110034, China; 2. State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The thermogravimetric analysis of a ternary Cu-25Ni-30Cr alloy prepared by conventional casting was performed in 0.1MPa pure O2 at 700-800℃. The results show that the alloy is composed of three phases, where the phase with the largest copper and lowest chromium content forms the matrix, while the other two, much richer in chromium, form a dispersion of isolated particles. At variance with another three-phase Cu-20Ni-20Cr alloy, which forms complex scales containing the oxides of the various components and double oxides plus an irregular region composed of alloy and oxides, the present alloy can form a very irregular but continuous chromia layer at the base of the mixed internal region, producing a gradual decrease of the oxidation rate down to very low values. A larger chromium content needed to form chromia layer for a ternary three-phase alloy is attributed to the limitations to the diffusion of the alloy components in the metal substrate imposed by their multiphase nature.
Key words: Cu-Ni-Cr alloy; three-phase; high-temperature oxidation
