Mo-MoSi2gradient coating on Mo substrate was prepared by siliconizing process,using the polysilicon as silicon atoms.The gradient layer was analyzed by the experimental results,theoretical analysis,and thermodynamic c...Mo-MoSi2gradient coating on Mo substrate was prepared by siliconizing process,using the polysilicon as silicon atoms.The gradient layer was analyzed by the experimental results,theoretical analysis,and thermodynamic calculation.The silicon,molybdenum content of gradient coating shows a gradual change regulation.The reaction between silicon and molybdenum is most likely to generate Mo5Si3,then MoSi2,finally Mo3Si,but when the silicon content is excessive,the Mo5Si3and Mo3Si will react with silicon and generate MoSi2.The gradient layer is mainly constituted by Si and MoSi2,only about 1/10 gradient layer is constituted by Mo5Si3and Mo3Si,and the stable existences of Mo5Si3and Mo3Si are mainly determined by the silicon content.Along the Mo substrate to the surface of the coating,the phase composition of gradient coating changes as follows:Mo → transition layer,Mo（main phase） + Mo3Si + Mo5Si3→intermediate layer,and MoSi2（main phase） + Mo5Si3+Si→surface layer MoSi2（main phase） + Si,and the experimental temperature has no effect on phase composition of gradient coating.展开更多
文摘在金属钼表面分别制备了MoSi2涂层和MoSi2/Si3N4涂层,利用SEM和XRD分析研究了涂层的微观结构和物相组成,并比较了涂层在1 450℃大气环境下的抗氧化性能.结果表明:两种涂层与基体结合好且均匀致密;MoSi2涂层钼氧化16 h后出现贯穿裂纹,破坏了SiO2保护膜的连续性,导致涂层失效;Si3N4相的引入可明显改善MoSi2基涂层钼的高温抗氧化性,其抗氧化时间达76 h.
基金financially supported by the National Natural Science Foundation of China (No. 50474079)Hebei Natural Science Foundation of China (No. E2010000945)
文摘Mo-MoSi2gradient coating on Mo substrate was prepared by siliconizing process,using the polysilicon as silicon atoms.The gradient layer was analyzed by the experimental results,theoretical analysis,and thermodynamic calculation.The silicon,molybdenum content of gradient coating shows a gradual change regulation.The reaction between silicon and molybdenum is most likely to generate Mo5Si3,then MoSi2,finally Mo3Si,but when the silicon content is excessive,the Mo5Si3and Mo3Si will react with silicon and generate MoSi2.The gradient layer is mainly constituted by Si and MoSi2,only about 1/10 gradient layer is constituted by Mo5Si3and Mo3Si,and the stable existences of Mo5Si3and Mo3Si are mainly determined by the silicon content.Along the Mo substrate to the surface of the coating,the phase composition of gradient coating changes as follows:Mo → transition layer,Mo（main phase） + Mo3Si + Mo5Si3→intermediate layer,and MoSi2（main phase） + Mo5Si3+Si→surface layer MoSi2（main phase） + Si,and the experimental temperature has no effect on phase composition of gradient coating.
基金National Natural Science Foundation of China(51674196,51601144,51701162)National Key Research and Development Program of China(2017YFB0702403)+1 种基金Innovative Talents Promotion Plan of Shaanxi(2019KJXX-071)Excellent Doctoral Innovation Fund of Xi’an University of Technology(310252071705)。
