A study on oxidation resistance of NiAl intermetallic compound

• Main Authors: Tzong-Dar Lee, 李宗達
• Other Authors: Chii-Shyang Hwang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/49152520535159171199

碩士 === 國立成功大學 === 材料科學(工程)研究所 === 83 === In order to improve the oxidation resistance of NiAl, the aimsave two parts: (A)nderstanding the isothermal oxidation behavior of NiAlompound at high temperature in air; (B) using (1)preoxidized in air, (2)thod,(3) hydrothermal anodic oxidation, respectively, to form oxiderface of NiAl, the effect of oxide scale on the oxidation resistance of NiAl is Experimental results show that the oxide scale on the surface oft >900℃ in air is alumina. The microstructure of oxide scale is alsoncreasing oxidation temperature. Surface of NiAl oxidized at 900℃,1000℃s dense scale of fine particle, porous scale of blade-like particles andales containing ridged layer grown up from the crack of inner layer, For the NiAl specimen preoxidized at 750℃ for 2hr in air, thenntain- ng .theta.-Al2O3 and .alpha.-Al2O3 is formed.The slower heatingeoxidized in air, the better oxidation resistance of NiAl. For the NiAl specimen treated by hydrothermal method at a40℃/28atm or 48hr, the oxide scale containing NiAl2O4 and NiO is formed.mal reatment and then cyclic oxidation at 1000℃ ～ 1200℃/15hr, thethe surface f NiAl has better densification than that of NiAl withouteatment. This result ndicates that the hydrothermal treatment can improve thetance of NiAl. For the NiAl specimen treated by hydrothermal anodic oxidationpplied urrnet density of 20mA/square centimeter at 240℃ /28atm/1hr in, the xide scale is AlOOH and NiO, respectively.