Ni-20Al丝材制备及涂层微结构特征研究

Preparation of Ni-20Al Wire and Microstructural Characteristic of the Related Coatings

开发了三种不同结构的Ni-20Al丝材,对其火焰喷涂工艺性和涂层微结构特征等进行分析,并与商用Metco 405NS丝材及所制备的涂层进行了对比。结果表明,丝材结构影响了火焰加热时热量由丝材表面向芯部的传导,导致丝材熔化状态产生显著差异,进而决定了喷涂焰流的稳定性以及相关涂层组织的均匀性。其中,采用轧制拉拔包丝技术制备的Ni-20Al丝材,呈现出优异的喷涂工艺稳定性,所制备的涂层组织均匀,平均显微硬度和结合强度分别可达348.3 HV_(0.05)、62 MPa,与405NS丝材制备涂层性能基本一致,具备了较好的应用潜力。

Three kinds of Ni-20Al wire with different structures were developed. The fame spraying suitability of three wires and the microstructural characteristics of related coatings were investigated, in comparison with the commercial 405NS wire and coatings. The results showed that the structure of Ni-20Al wire affected the heat transfer within wires during flame spraying, leading to significant differences in the melting state of the wires, which determined the stability of spraying process and the uniformity and microstructure of the related coatings. Consequently, the Ni-20Al wire prepared by rolling-drawing process with solid Ni wire flled exhibited an excellent stability during spraying process. The as-deposited coating depicted uniform microstructure with an average microhardness of 348.3 HV_(0.05)and a bonding strength of 62 MPa, which were in accordance with the coatings prepared by spraying 405NS wire. Therefore, the developed Ni-20Al wire here presented a great potential in application.