| 摘要 |
A MoSi2-Si3N4 composite coating which is coated on a surface of base materials which are molybden, molybden alloy, molybden-coated niobium or molybden-coated niobium alloy and a manufacturing method thereof. The MoSi2-Si3N4 composite coating on the surface of the base material can be formed by forming a Mo2N diffusion layer by vapor-depositing of nitrogen on the surface of the base material and forming a MoSi2-Si3N4 composite coating by vapor-depositing of silicon on the surface of the Mo2N diffusion layer, or the MoSi2-Si3N4 composite coating on the surface of the base material can be formed by forming a MoSi2 diffusion layer by vapor-depositing of silicon on a surface of a base material by the CVD method, transforming the MoSi2 diffusion layer into a Mo5Si3 diffusion layer by heating under a high-purity hydrogen or argon atmosphere, forming a Mo2N-Si3N4 composite diffusion layer by vapor-depositing of nitrogen on the surface of the Mo5Si3 diffusion layer by the CVD method and forming a MoSi2-Si3N4 composite coating by vapor-depositing of silicon on the surface of the Mo2N-Si3N4 composite diffusion layer. The MoSi2-Si3N4 composite coating manufactured by the above method is characterized as a structure in which Si3N4 particles are distributed in a MoSi2 grain boundary of equiaxed grains, thus to improve cyclic oxidation resistance of the base material, improve low-temperature oxidation resistance, and improve mechanical properties of the coating. Therefore, transmission of fine cracks by the thermal stress can be restrained.
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