研究表面涂Na2SO4盐膜的改性Ti3Al基合金在910和950℃ 空气中的热腐蚀行为,并分别采用XRD和SEM等测试技术分析腐蚀产物的物相组成,观察腐蚀产物表面及截面的形貌特征.原位热重分析结果表明合金遭受了严重的热腐蚀,腐蚀动力学曲线表现出两个阶段的特征,腐蚀产物膜由疏松多孔的TiO2、Nb2O5和Al2O3混合氧化物组成.热腐蚀过程中合金表面形成了大量的瘤状产物,绘制了详细描述这些瘤状产物形成及发展过程的示意图.由于局部的酸性溶解过程,难熔金属氧化物对热腐蚀过程的发展具有决定性作用.%The hot corrosion behaviour of a modified Ti3Al-based alloy under thin Na2SO4 deposit film was investigated at 910 and 950 ℃ in air. The corrosion product was identified by XRD and its morphologies on the surface and cross-section were observed by SEM. The alloy suffered from considerable hot corrosion attack. The mass gain versus time curves obtained by TGA exhibited two regions of different kinetics. The whole corroded layer consisted of loose and porous mixture oxides of TiO2, Nb2O5 and Al2O3. Numerous small nodules of corrosion product were observed. An illustrative schematic was established to describe the formation process of such nodules. It seemed that the refractory oxides played a significantly important role in determining the development of hot corrosion attack.
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