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研究了由γ′*Co_3(Al,W)相沉淀强化的新型钴基Co-Al-W高温合金在800℃、75%Na_2SO_4+25%NaCl熔盐中的热腐蚀动力学及合金元素Mo、Nb、Ta和Ti对合金热腐蚀行为的影响。研究发现,2Mo、2Nb、2Ta和2Ti合金比9.8W合金具有更好的抗热腐蚀能力,Mo和Ti对提高合金耐热腐蚀能力的效果比Ta和Nb显著。加入合金元素的合金热腐蚀膜由三层组成,即主要由Co氧化物CoO和Co_3O_4组成的腐蚀膜外层,由合金元素、Al、Co及W复杂氧化物组成的中间过渡层和由Al、Co氧化物组成的腐蚀膜内层。随着腐蚀时间的增加,中间过渡层厚度逐渐增加,热腐蚀膜内、外层厚度变化不大,但内层致密性逐渐增加。
The kinetics of hot corrosion of the new Co-based Co-Al-W superalloy strengthened by γ ’* Co_3 (Al, W) phase precipitation in a molten salt of 75% Na_2SO_4 + 25% Effect of Nb, Ta and Ti on Hot Corrosion Behavior of Alloys. The results show that 2Mo, 2Nb, 2Ta and 2Ti alloys have better corrosion resistance than 9.8W alloy, while Mo and Ti are more effective than Ta and Nb in improving the corrosion resistance of alloys. Alloying elements added to the alloy hot corrosion film consists of three layers, namely, mainly composed of Co oxide CoO and Co_3O_4 corrosion film outer layer, the alloying elements, Al, Co and W complex oxide intermediate layer and transition layer composed of Al, Co oxide corrosion film inner layer. With the increase of corrosion time, the thickness of the intermediate transition layer gradually increases. The thickness of the inner and outer layers of the hot corrosion film does not change much, but the density of the inner layer gradually increases.