| 摘要 |
A MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>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 MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>composite coating on the surface of the base material can be formed by forming a Mo<SUB>2</SUB>N diffusion layer by vapor-depositing of nitrogen on the surface of the base material and forming a MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>composite coating by vapor-depositing of silicon on the surface of the Mo<SUB>2</SUB>N diffusion layer, or the MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>composite coating on the surface of the base material can be formed by forming a MoSi<SUB>2 </SUB>diffusion layer by vapor-depositing of silicon on a surface of a base material by the CVD method, transforming the MoSi<SUB>2 </SUB>diffusion layer into a Mo<SUB>5</SUB>Si<SUB>3 </SUB>diffusion layer by heating under a high-purity hydrogen or argon atmosphere, forming a Mo<SUB>2</SUB>N-Si<SUB>3</SUB>N<SUB>4 </SUB>composite diffusion layer by vapor-depositing of nitrogen on the surface of the Mo<SUB>5</SUB>Si<SUB>3 </SUB>diffusion layer by the CVD method and forming a MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>composite coating by vapor-depositing of silicon on the surface of the Mo<SUB>2</SUB>N-Si<SUB>3</SUB>N<SUB>4 </SUB>composite diffusion layer. The MoSi<SUB>2</SUB>-Si<SUB>3</SUB>N<SUB>4 </SUB>composite coating manufactured by the above method is characterized as a structure in which Si<SUB>3</SUB>N<SUB>4 </SUB>particles are distributed in a MoSi<SUB>2 </SUB>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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