PHASE TRANSFORMATION OF Al-Ti COATINGS ON Co-BASE SUPERALLOY DZ40M DURING HIGH TEMPERATURE OXIDATION

来源期刊：中国有色金属学报(英文版)1998年第4期

论文作者：Liu Peisheng Sun Xiaofeng Jin Tao Guan Hengrong Hu Zhuangqi

文章页码：583 - 587

Key words：Co-base superalloy　,coating　,phase transformation

Abstract: Both the formation of simple aluminide and Ti-modified aluminide coating on Co-base superalloy DZ40M and the phase transformation in high temperature oxidation have been studied. The results indicate that the deposition coatings consist of an outer layer of CoAl phase and an internal layer of Cr,W,Ti-rich carbide zone. The transformation of the phase for all these coatings has occurred as follows: CoAl→CoAl(majority)+α-Co→α-Co (majority) + CoAl→α-Co at a high temperature of 900~1100℃. The appearance of α-Co marks the beginning of degradation which is over when all of CoAl changes intoα-Co. The addition of Ti into reagent during deposition can lower the Al-activity, reduce the Al-content and thickness of coatings relevantly, and speed up the degradation of coatings.