预氧化提高Ti-48Al-2Nb-2Cr合金的抗热腐蚀性能  

Improving of Hot Corrosion Resistance of Ti-48Al-2Nb-2Cr Alloy Via Pre-Oxidation

作　　者：李哲轩 梁君岳 李鑫奇 刘会军 伍廉奎 LI Zhexuan;LIANG Junyue;LI Xinqi;LIU Huijun;WU Liankui(School of Materials,Sun Yat-Sen University,Shenzhen 518107,China;Songshan Lake Materials Laboratory,Dongguan 523808,China)

机构地区：[1]中山大学材料学院,广东深圳518107 [2]松山湖材料实验室,广东东莞523808

出　　处：《材料研究与应用》2022年第6期896-904,共9页Materials Research and Application

基　　金：国家自然科学基金项目(52271084);广东省自然科学基金项目(2021B1515020056);大学生创新创业训练计划(202211696)。

摘　　要：TiAl合金具有优异的高温性能,但在高温下的抗氧化性和耐腐蚀性较差,从而阻碍了其在工程中的实际应用。以Ti-48Al-2Nb-2Cr合金为研究对象,为其免受热腐蚀侵蚀,通过预氧化在其表面制备一层致密的保护膜,研究预氧化处理对Ti-48Al-2Nb-2Cr合金在Na_(2)SO_(4)(质量分数75%)+NaCl(质量分数25%)混合盐环境中的热腐蚀行为及氧化层组成和结构的影响。结果表明:经700℃氧化100 h后,预氧化试样的氧化增重仅有0.47 mg·cm^(-2);预氧化处理的Ti-48Al-2Nb-2Cr合金表面为多层氧化物结构,最外层形成了连续、致密的TiO_(2)层,并且氧化层与基体具有良好的结合力,从而有效阻止了熔盐向合金内部扩散,进而显著提高了合金的抗热腐蚀性能。因此,通过预氧化的方式可提高TiAl合金表面的抗热腐蚀性能。To protect Ti-48Al-2Nb-2Cr alloy from hot corrosion at elevated temperatures,a compact protective coating was prepared on the surface of alloy by pre-oxidation process. The effects of pre-oxidation treatment on the hot corrosion behavior and oxide layer composition and structure of Ti48Al2Nb2Cr alloy were studied in the mixed salt consisting of 75 wt. % Na_(2)SO_(4)and 25 wt. % NaCl at 700 ℃ for 100 h. The results showed that the surface of the pre-oxidized Ti-48Al-2Nb-2Cr alloy had a multi-layer oxide structure,and a continuous and dense TiO_(2)layer was formed in the outermost layer. At the same time,the oxide layer had a good adhesion with the matrix,which could effectively prevent the inward diffusion of molten salt,thus significantly improving the hot corrosion resistance of the alloy. After oxidation at 700 ℃ for 100h,the mass gain of the PO-Ti48Al2Nb2Cr alloy was only 0. 47 mg·cm^(-2). Therefore,the anti-hot corrosion performance of TiAl alloy could be effectively improved via pre-oxidation process.

关 键 词：Ti-48Al-2Nb-2Cr合金 耐热腐蚀性 预氧化 热腐蚀动力学 热腐蚀机制 

分 类 号：TG174.4[金属学及工艺—金属表面处理]