钴对镍基高温合金抗热腐蚀性能影响的研究

用以Udimet500为基0～25%七种不同钴含量的合金在750℃、800℃、850℃含100ppm盐雾气氛中进行单管热腐蚀试验,试验时间为62.5小时。宏观观察及失重法结果表明,钴可以明显改善和提高合金的抗热腐蚀性能。 用光学显微镜、X-光、电子探针及辉光逐层分析等方法进行了微观分析。结果指出,增加合金钴含量有益于合金在热腐蚀孕育期形成连续的保护性氧化膜,提高氧化膜的粘附性。钴还可以有效地阻止硫在合金中的扩散。

The Effect of Cobalt on the Hot Corrosion Behavior of Ni-Base Superalloys

The hot corrosion behavior of seven superalloys of Udimet 500 system with different Co amounts was studied by burner-rig test at 750℃,800℃,850℃ in an atmosphere containing 100 ppm salt. Total time of test was 62,5 hours. Experimental results showed that the corrosion resistance of these alloys were markedly improved by cobalt. The microstructures were studied with optical microscope, X-ray diffraction,electron probe and glow discharge spectro scopy analysis. It was observed that Co was beneficial to form a cotinuous protective oxide film on the surfaces of alloys with improved adhesion during the incubation period of hot corrosion. Moreover, Co in the superalloys can effectively retard the diffusion of sulphur in these alloys.