Comparative Study of Oxidation Behavior of Cr2O3 Dispersed W-Zr Alloys at 800°C, 1000°C and 1200°C Fabricated Using Powder Metallurgy

Oxidation behavior at 800°C, 1000°C and 1200°C of nano-Cr 2 O 3 dispersed W-Zr alloys fabricated using mechanical milling followed by conventional sintering at 1500°C in inert atmosphere is discussed. Three different alloys were designated as W-0.5Zr-1Cr 2 O 3 (alloy A), W-0.5Zr-2Cr 2 O 3 (alloy B), and W-1Zr-1Cr 2 O 3 (alloy C) (in wt.%). The application range of W is greatly restricted by oxidation, necessitating the use of suitable alloying and dispersion techniques. Upon exposure to 800°C, alloy A exhibited the highest level of oxidation resistance, whereas alloy B demonstrated superior performance at 1000°C and 1200°C. This enhanced oxidation resistance in alloy B can be attributed to its microstructure, characterized by a fine and uniform distributed Cr 2 O 3 -rich and Zr-rich phase. At 800°C, protection against oxidation primarily resulted from improved densification, enhanced adhesion of oxide scale with the matrix phase, and decreased volatilization of WO 3 . However, at ≥ 1000°C, the development of Cr 2 WO 6 seems to play a vital role. Higher activation energy was also observed in the current alloys compared to pure W, attributed to the combined influence of Cr 2 O 3 and Zr dispersion. This study offers valuable insights into the development of oxidation-resistant alloys through Cr 2 O 3 dispersion, particularly applicable for high-temperature applications.