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

Oxidation behavior at 800 degrees C, 1000 degrees C and 1200 degrees C of nano-Cr2O3 dispersed W-Zr alloys fabricated using mechanical milling followed by conventional sintering at 1500 degrees 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 degrees C, alloy A exhibited the highest level of oxidation resistance, whereas alloy B demonstrated superior performance at 1000 degrees C and 1200 degrees C. This enhanced oxidation resistance in alloy B can be attributed to its microstructure, characterized by a fine and uniform distributed Cr2O3-rich and Zr-rich phase. At 800 degrees C, protection against oxidation primarily resulted from improved densification, enhanced adhesion of oxide scale with the matrix phase, and decreased volatilization of WO3. However, at >= 1000 degrees C, the development of Cr2WO6 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 Cr2O3 and Zr dispersion. This study offers valuable insights into the development of oxidation-resistant alloys through Cr2O3 dispersion, particularly applicable for high-temperature applications.