【摘要】 目前,鲜见对Ti₂AlNb合金表面渗镀Al层在高温熔盐环境中耐腐蚀性能的报道。采用加弧辉光等离子渗镀技术在Ti₂AlNb合金表面渗镀Al层。采用扫描电镜、X射线衍射仪分析了渗镀Al层的形貌、结构及相组成;采用涂盐热腐蚀试验研究了渗镀Al层在750℃的Na₂SO₄熔盐中的热腐蚀行为。结果表明:渗镀Al层由外层纯Al沉积层和内层Al-Ti-Nb扩散层组成,其组织均匀致密,与基体结合良好;在750℃的Na₂SO₄熔盐中,Ti₂AlNb合金基体腐蚀增重显著,腐蚀产物出现明显的层状剥落现象,耐热腐蚀性较差,而渗镀Al层试样仅发生微小的增重,腐蚀100 h后,内部扩散层还比较完整,未出现氧化和硫化的现象,仍拥有足够的Al源来抵抗接下来的腐蚀进程。更多还原

【Abstract】 An aluminized layer was prepared on Ti₂AlNb alloy surface by arc-added glow discharge plasma surface alloying technique.The scanning electron microscopeand X-ray diffraction were used to analyze the morphology,structure and phase compositions of aluminized layer.Hot- corrosion behavior of the layer as well as Ti₂AlNb substrate in Na₂SO₄ molten salt at 750℃ was studied.Results showed that the aluminized layer,which was consisted of an outer layer of pure Al deposition and an inner Al-Ti-Nb mutual diffusion layer,was dense and adhered tightly to the Ti₂ AlNb substrate.The mass of Ti₂AlNb substrate increased remarkably when corroded in sulfate salt at 750℃ and lamellar spallation in the corrosion products was observed,which indicated that the substrate had poor hot corrosion resistance.Meanwhile,the aluminized layer only increased slightly.After corroded for 100 h,the inner diffusion layer was still integrate,and no oxidation or sulfuration was observed in this layer.The inner layer still provided enough Al source to inhibit the hotcorrosion.更多还原