激光熔覆镍包纳米氧化铝

Ni-Coated Nano-Al_2O_3 Composite Coating Prepared by Laser Cladding

进行了2Cr13不锈钢表面激光熔覆镍包纳米氧化铝的实验。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线能量色散谱仪(EDAX)、显微硬度仪等设备检测了涂层表面、横截面的显微组织和涂层的硬度、耐磨损等性能,分析了加入纳米氧化铝粒子后对涂层组织和性能的影响。研究结果表明,激光熔覆可获得致密的Fe-Ni(Cr)合金和Al2O3粒子复合涂层。其中,纳米氧化铝粒子弥散分布在微细合金晶粒之间,并与合金晶粒一起形成了胞状树枝晶结构。纳米氧化铝粒子的加入增加了基质金属的成核率,起到了细晶强化以及弥散强化的作用,使得复合涂层的机械性能大幅度提高。复合涂层的平均硬度为700HV0.2,比基体提高了1.5倍,耐磨损性能比淬火态基体提高了1.25倍。

The experiments of laser cladding Ni-coated nano-Al2O3 composite powder were made on 2Cr13 stainless steel using 7 kW CO2 laser processing system. The microstructure and mechanic performances of coating were tested by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, energy dispersion analyzer of X-ray （EDAX） and microhardness tester. The changes of microstructure and performances after adding nano-particles were analyzed. The results have shown that the dense Fe-Ni（Cr）/Al2O3 composite coating can be got by laser cladding. The coating exhibited a cellular dendritic structure. The XRD data revealed that the phases of composite coating include Al2O3, iron nickel alloy and iron chromium alloy. Nano-Al2O3 particles enhanced the homogeneous nucleation of metal alloys, refined the crystal grains and strengthened the mechanical properties of coating. The average hardness of composite coating is about 700HV0.2, 1.5 times higher than that of substrate. Compared with substrate, the abrasion proof has increased by 125 %.