Microstructure and oxidation resistance of Mo–Si and Mo–Si–Al alloy coatings prepared by electro-thermal explosion ultrahigh speed spraying

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 518; no. 1; pp. 108 - 117
• Main Authors: Hou, Shi-xiang, Liu, Zong-de, Liu, Dong-yu, Li, Bao-rang, Zhang, Nai-qiang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 25.08.2009; Elsevier
• Subjects: Applied sciences; Corrosion; Corrosion prevention; Electro-thermal explosion ultrahigh speed spraying; Exact sciences and technology; Metals. Metallurgy; Microstructure; Mo–Si and Mo–Si–Al alloy coatings; Oxidation resistance; 68.47.Gh; Oxidation resistance; Electro-thermal explosion ultrahigh speed spraying; 81.16.Be; Mo–Si and Mo–Si–Al alloy coatings; 81.15.Rs; Microstructure; Grain size; Electro-thermal explosion ultrahigh speed; Silicon alloy; Submicrometer; Electrothermics; Aluminium alloy; High temperature; spraying; Spray coating; Microhardness; Mo-Si and Mo―Si―Al alloy coatings; Molybdenum alloy; Transition metal alloy; Oxidation
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2009.04.026

Mo–Si and Mo–Si–Al alloy coatings were synthesized on the surface of nickel-based superalloy substrate using electro-thermal explosion ultrahigh speed spraying technology. The coatings have dense microstructure with submicrometer size grains. The microhardness of the coatings is in the range of 1100–1350 HV. The weight loss of Mo–Si alloy coatings is found to be 2 mg/cm 2 on exposure at 500 °C for 840 h and 20 mg/cm 2 on holding at 900 °C for 360 h, respectively. However, Al alloyed in Mo–Si coatings obviously slows down the oxidation at high temperature. The weight loss of Mo–Si–Al alloy coatings is only 0.5 mg/cm 2 at 500 °C for 840 h and 7 mg/cm 2 at 900 °C for 360 h, respectively. The weight loss ratio of Mo–Si–Al alloy coatings decreases about 70% comparing to that of Mo–Si alloy coatings. The pest disintegration of the MoSi 2 can be suppressed by electro-thermal explosion ultrahigh speed spraying technology and alloying Al.