A MoSi2-based composite coating by supersonic atmospheric plasma spraying to protect Nb alloy against oxidation at 1500 degrees C

作者：Sun, Le; Fu, Qian-Gang^*; Fang, Xiang-Qing; Sun, Jia

来源：Surface and Coatings Technology, 2018, 352: 182-190.

DOI：10.1016/j.surfcoat.2018.07.091

• MoSi2-based composite coating
• Nb alloys
• Supersonic atmospheric plasma spraying
• Oxidation
• Diffusion

A MoSi2-based oxidation resistant coating was directly deposited on Nb alloy substrate by supersonic atmospheric plasma spraying using pure agglomerated MoSi2 powders. The as-received coating mostly consisted of hMoSi(2), t-MoSi2 and Mo5Si3 in a typical layer structure. The cyclic oxidation test of the MoSi2-based composite coating was evaluated at 1500 degrees C in air. The formed multi-layer of the coating included SiO2 outer layer, Mo5Si3 + MoSi2 + SiO2 middle layer and Nb5Si3 transitional layer after oxidation. The results show that the mass loss of the coated sample was 5.31 mg/cm(2) after exposure at 1500 degrees C in air for 43 h. The excellent protective ability against oxidation of the MoSi2-based composite coating could be mainly attributed to a continuous protective SiO2 scale and an adhesive Nb5Si3 diffusion layer, which ensured the low oxygen diffusion rate and the strong bonding to the substrate.

• 出版日期2018-10-25
• 单位凝固技术国家重点实验室; 西北工业大学