摘要
MoSi_(2)涂层因其良好的高温抗氧化性、抗热腐蚀性等优点,被认为是目前理想的高温防护材料之一,然而涂层与基体热膨胀系数不匹配、界面互扩散等问题会严重影响MoSi_(2)涂层的抗氧化性能。本工作通过电弧熔覆技术在Mo基体上制备了不同配比的Nb、W合金化MoSi_(2)涂层,研究了在高温氧化环境下Nb、W元素对MoSi_(2)涂层的组织、形貌以及抗氧化性的影响。结果表明,添加2%Nb形成的C11_(b)/C40型(Mo,Nb)Si_(2)会增加涂层和氧化层中的缺陷,添加4%W能够提高涂层和氧化层的致密度,添加10%W对氧化层的致密性不利。根据氧化动力学曲线可知,添加4%W以及添加2%Nb+4%W的MoSi_(2)涂层呈氧化增重趋势,在氧化过程中形成了较为致密的氧化膜。通过结合氧化动力学曲线计算抛物线速度常数值,发现MoSi_(2)的氧化速率随着Nb、W含量的增加而提高。单一添加Nb元素对MoSi_(2)氧化层厚度的影响很小,Nb、W协同合金化后氧化层的厚度提升显著。氧化激活能计算结果表明,添加2%Nb+4%W的MoSi_(2)涂层氧化激活能最高,约为纯MoSi_(2)的2.4倍,高温抗氧化性最佳。
MoSi_(2)coating is considered as one of the ideal high-temperature protective materials at present because of its good high-temperature oxidation resistance,thermal corrosion resistance,etc.However,the mismatch of thermal expansion coefficient between the coating and the substrate and interfacial interdiffusion problems seriously affect the antioxidant performance of MoSi_(2)coating.In this work,Nb-and W-alloyed MoSi_(2)coatings with different ratios were prepared on Mo substrate by arc cladding technology,and the effects of Nb and W elements on the organization,morphology,and oxidation resistance of MoSi_(2)coatings were investigated under high-temperature oxidizing environment.The results show that the C11_(b)/C40-type(Mo,Nb)Si_(2)formed by the addition of 2%Nb increases the defects in the coating and the oxide layer,and the addition of 4%W improves the densities of the coating and the oxide layer,while the addition of 10%W adversely affects the densification of the oxide layer.According to the oxidation kinetic curves,the MoSi_(2)coatings with 4%W and with 2%Nb+4%W showed a trend of oxidative weight gain,and a denser oxide film was formed during the oxidation process.By correlating the oxidation kinetic curves to derive the parabolic velocity constants,it becomes evident that the oxidation rate of MoSi_(2)accelerates with increasing Nb and W content.The impact of adding a single element of Nb on the thickness of the MoSi_(2)oxide layer is minimal,whereas the synergistic alloying of Nb and W leads to a notable increase in oxide layer thickness.Oxidative activation energy calculations indicate that the MoSi_(2)coating with 2%Nb+4%W has the highest oxidation activation energy,which is about 2.4 times that of pure MoSi_(2),and has the best high-temperature antioxidant performance.
作者
王玉瑞
孙洪飞
孙顺平
王洪金
赵凤玲
张扬
李小平
WANG Yurui;SUN Hongfei;SUN Shunping;WANG Hongjin;ZHAO Fengling;ZHANG Yang;LI Xiaoping(School of Materials Engineering,Jiangsu University of Technology,Changzhou 213001,Jiangsu,China)
出处
《材料导报》
北大核心
2025年第10期159-165,共7页
Materials Reports
基金
中国博士后科学基金(2019M650096)
江苏省高等学校自然科学基金重大项目(21KJA430009)
常州市科技支撑计划(社会发展)(CE20235041)
江苏省自然科学基金(BK20241969)。
