激光熔覆Ni-Zr-Nb-Al非晶复合涂层组织结构及性能研究

为了制备Ni基非晶涂层,采用激光熔覆方法在45#钢基体上制备Ni60.5Zr19.63Nb18.07Al1.8非晶复合涂层,分析了涂层显微组织及物相,测得了表征力学及耐蚀性能的实验数据。结果表明,涂层中存在大量呈树枝状和胞状的晶体相,由X射线衍射分析可知,涂层中出现了非晶及NiZr2,Ni5Nb,Al2O3和Fe-Ni金属间化合物等物相;当功率为3600W时,涂层中白色非晶相含量最多,且组织最为细小;功率为3000W时,涂层最高硬度在最表面,达到2399.9HK,表面耐磨失重为0.5921mg·mm-2;涂层耐蚀性能在功率为3600W时最佳,致钝电流密度最小为3.05mA/m2,钝化区间最宽为1170mV。由新判据设计的Ni60.5Zr19.63Nb18.07Al1.8成分具有较强非晶形成能力。

Study on microstructure and performance of laser cladding Ni-Zr-Nb-Al amorphous composite coating

In order to prepare Ni-based amorphous coatings,Ni60.5Zr19.63Nb18.07Al1.8 amorphous composite coating was prepared on 45 steel substrate by means of laser cladding.Then the microstructure and phase of the coating were analyzed and the parameters characterizing the mechanical and corrosion resistance were measured.The results show that a great deal of dendritic and cystiform crystal phases exist in the coating.X-ray diffraction analysis reveals that amorphous,intermetallic compound such as NiZr2,Ni8 Nb,Al2O3 and Fe-Ni,and some other phases present in the coating.Content of white amorphous phase is up to maximum at the power of 3600W,and microstructure is most fine;hardness reaches maximum at the power of 3000W and can be up to 2399.9HK at topmost surface,while surface wear weight loss is 0.5921 mg·mm-2;coating corrosion resistance is the best at the power of 3600W.The minimum obtuse current density is 3.05mA/m2,and passive potential widest range is 1170mV;Ni60.5Zr19.63Nb18.07Al1.8 designed according to the new criterion has strong glass forming ability.