Ni-Al包覆增强Fe基非晶涂层的结构与耐磨性

为了降低Fe基非晶涂层的孔隙率,并提高其耐摩擦性能,采用机械球磨法在铁基非晶颗粒表面包覆Ni-Al颗粒,得到具有壳-核结构的涂层复合喷涂粉末,并采用等离子喷涂法将其在45钢表面制备铁基非晶涂层;分析了包覆型复合粉末和Fe基复合涂层的相组成和微观结构,测试了复合涂层的孔隙率、非晶相比例和干摩擦性能,研究了Ni-Al粒子包覆前后涂层的微观结构与摩擦机理变化。结果表明:Ni-Al粒子成功包覆在Fe基非晶表面形成了结构致密的壳-核结构复合粉末,粉末粒径小于50μm,包覆层厚度1~3μm。涂层孔隙率下降5%左右,由于Ni-Al稀释作用,非晶含量由72.5%降低为64.8%,复合涂层的结构显示为Ni3Al相和Fe基非晶形成的层片状。相对于传统涂层结构,复合涂层更能够强化非晶涂层的层状堆积的优点。相比Fe基非晶涂层,复合涂层的摩擦系数由0.412 3降低到0.256 1,磨损量为原涂层的1/2左右。Ni-Al粒子通过改进Fe基非晶粒子的熔解形态和延展能力,有效提高了非晶涂层的致密度,涂层非晶含量降低不明显,耐磨性显著增强。

Structure and Wear Resistance of Fe-Based Amorphous Coatings Coated with Ni-Al

In order to reduce the porosity of Fe-based amorphous coating and improve its friction resistance,Ni-Al particles were coated on the surface of Fe-based amorphous particles by mechanical ball milling. The composite coating powders with shell-core structure were obtained and used for preparing Fe-based amorphous coatings by plasma spraying method. Subsequently,the phase composition and microstructure of coated composite powders and Fe-based composite coatings were analyzed,and the porosity,amorphous ratio and dry friction properties of the composite coatings were tested. In addition,the changes of microstructure and friction mechanism of the coatings before and after Ni-Al particle coating were studied. Results showed that Ni-Al particles were successfully coated on Fe-based amorphous surface to form a compact shell-core composite powder,of which the particle size was less than 50 μm and the coating thickness was 1 ~ 3 μm. The porosity of the coating decreased by about 5%,and the amorphous content decreased from 72. 5% to 64. 8% due to the dilution of Ni-Al. Moreover,the structure of the composite coating presented lamellar structure was formed by Ni3 Al phase and Fe-based amorphous phase. Compared with the traditional coating structure,the composite coating could strengthen the advantages of layered amorphous coating. In the compassion of Fe-based amorphous coatings,the friction coefficient of composite coating decreased from 0.412 3 to 0.256 1,and the wear amount was about half of the original coating. By modifying the melting morphology and ductility of Fe-based amorphous particles,Ni-Al particles could effectively improve the density of amorphous coatings. Furthermore,the amorphous content of the coatings was not significantly reduced,while the wear resistance was significantly enhanced.