Microstructure and anti-oxidation behavior of laser clad NiSi coating on molybdenum surface

• Published in: International journal of refractory metals & hard materials Vol. 120
• Main Authors: Deng, Lang, Huang, Can, Zhao, Yingying, Liu, Hao, Huang, HaoZhen, Lin, Mengrui, Duan, Huming, Zhao, Shunhui, Mo, Jinyong, Tu, Jian, Chang, Xia, Zhou, Zhiming
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2024
• Subjects: Laser cladding; Microstructure; Molybdenum; Ni-Si; Oxidation behavior; Ni-Si; Oxidation behavior; Laser cladding; Microstructure; Molybdenum
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2024.106570

Ni-Si alloy coatings with various compositions were fabricated on molybdenum surfaces using laser cladding technology. The sound metallurgical bond without cracks and pores between coatings and substrat was revealed.The microstructure and phase composition of the coatings were analyzed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The oxidation resistance of the coatings was investigated in a static air environment at 700 °C. The results reveal that the coatings primarily consist of a γ-Ni solid solution, Ni3Si phase, and Mo2Ni3Si phase. Furthermore, the Mo2Ni3Si phase content increases with decreasing Ni content in the powder ratio. The oxidation kinetics curve of the NiSi alloy coatings follows a parabolic law. The oxide layer formed on the coating surface is uniform and dense, comprising SiO2, MoO3, and NiMoO4. Based on the comprehensive analysis of the microstructure of the oxide layer, the Ni90Si10 coating demonstrated superior oxidation resistance •This study prepared NiSi coatings on molybdenum surfaces by laser cladding to improve the oxidation resistance at 700 °C.•The coatings are primarily composed of a γ-Ni solid solution, Ni3Si phase, and Mo2Ni3Si phase. Interestingly, the Mo2Ni3Si phase content increased with reduced Ni content in the powder ratio.•The oxidation kinetics of the NiSi alloy coatings conformed to a parabolic law, resulting in a uniform and dense oxide layer on the surface, comprising SiO2, MoO3, and NiMoO4.•A comprehensive microstructure analysis of the oxide layer highlighted the exceptional oxidation resistance of the Ni90Si10 coating.