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紧耦合气雾化制备热喷涂NiCrAlY合金粉

Thermal spraying NiCrAlY alloy powders prepared by close-coupled gas atomization

  • 摘要: 采用紧耦合气雾化技术制备热喷涂NiCrAlY合金粉末,对NiCrAlY合金粉末的物理性能、粒度分布、粉末形貌、微观结构和物相组成等进行了分析。结果表明,粉末以球形和近球形颗粒为主,85%粉末粒径小于150 μm。粉末显微组织主要由树枝晶和胞状晶组成,粒径25~250 μm的粉末凝固冷速大约在4000~67000 K·s−1。粒径尺寸小于50 μm的粉末内部结构致密,少量尺寸大于50 μm的颗粒内部出现凝固缩孔和空心缺陷。粉末晶界和晶内存在Y、Si元素偏析,粉末物相结构主要由γ'-Ni3Al、γ-Ni固溶体相组成。

     

    Abstract: NiCrAlY alloy powders used for the thermal spraying were fabricated by the closed-coupled gas atomization technology. The physical properties, particle size distribution, powder morphology, internal microstructure, and phase composition of the NiCrAlY alloy powders were investigated. The results show that, most of powders are spherical or nearly spherical particles, the particle size of 85% powders is less than 150 μm. The powder microstructures are mainly composed of dendrites and cellular crystals, and the solidification cooling rate of the powders with the particle size of 25~250 μm is about 4000~67000 K·s−1. The inner structure of the powders with the particle size less than 50 μm is dense, and a small number of particles with the particle size larger than 50 μm show the solidification shrinkage pore and hollow defects. There are Y and Si segregation in the crystal boundary and intracrystalline, and the powder phases are mainly composed of γ'-Ni3Al and γ-Ni solid solution phases.

     

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