Ni-Cr-Co基高温合金在含有水蒸汽的空气中的高温腐蚀行为

High Temperature Corrosion Behavior of Ni-Cr-Co Base Superalloy in Air with Water Vapor

利用热重分析法、SEM(EDX)和X射线衍射研究了一种Ni-Cr-Co基高温合金在两种不同水蒸汽含量的空气中的高温腐蚀行为.结果表明:合金在750℃含有10％H_2O的空气中的腐蚀动力学规律为先遵从抛物线后遵从直线规律,试样表面形成Cr_2O_3层,并且有内氧化物生成.合金在775℃含有5％H_2O的空气中腐蚀时,试样表面致密的氧化层由Cr_2O_3,TiO_2和CoCr_2O_4组成,同时也发生了内氧化现象.水蒸汽加速了合金的腐蚀速度.整个腐蚀过程由元素通过氧化膜的传输控制.

By means of TGA, SEM (EDX) and XRD, the high temperature corrosion behavior of Ni-Cr-Co base superalloy was studied at 750°C and 775°C in air with water vapor. The results indicate that the kinetic curve of the alloy oxidized at 750°C for 2480 h in air with 10% water vapor obeys a parabolic law at the initial oxidation stage and then follows a linear law. The oxide scale mainly consists of Cr2O3 and the internal oxides, A12O3 and TiO2, also precipitate in matrix. The protective oxide scale of the alloy oxidized at 775°C for 432 h in air with 5% water vapor is composed of Cr2O3, TiO2 and CoCr2O4 and the internal oxides are A12O3 and TiO2. The corrosion speed is quickened because of the presence of water vapor. The corrosion procedure is decided by the transmission of the elements through the oxide scale.