Environmental corrosion resistance of porous TiAl intermetallic compounds
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. The Third Xiangya Hospital, Central South University, Changsha 410013, China)
2. The Third Xiangya Hospital, Central South University, Changsha 410013, China)
Abstract: Porous TiAl intermetallic compound, as a novel substitute for current inorganic porous material, offsets the shortages of both ceramics and metals. The environmental corrosion resistance of porous TiAl intermetallic compound was investigated. The kinetic equation for the cyclic oxidation of porous TiAl alloy at 600 ℃ is determined to be Δm2=1.08×10−5t. After total oxidation of 140 h, porous TiAl intermetallic compound shows more stability of pore structure and the mass gain of TiAl alloy is 0.042 g/m2, which is only 10.6% that of porous 316L stainless steel. The kinetic equation for the cyclic corrosion behavior of porous TiAl alloy in hydrochloric acid with pH=2 at 90 ℃ is determined to be Δm2=5.41×10−5t−2.08×10−4. After 50 h exposure, the mass loss of TiAl alloy is 0.049 g/m2, which is only 14.8% and 5.57% that of porous Ti and stainless steel, respectively. The kinetic equation in hydrochloric acid with pH=3 is determined to be Δm2=2.63×10−6t−3.72×10−6.
Key words: TiAl intermetallic compound; porous material; high temperature oxidation resistance; corrosion resistance