基于大气等离子喷涂的镍铬基粉末制备及其涂层组织结构

Preparation of Nickel-Chromium Based Powder and Microstructure of Its Atmospheric Plasma Spraying Coating

以高能球磨后的镍基合金、银、氟化物共晶复合粉末为原料,采用喷雾干燥和烧结技术制备了粒径为20~110μm的热喷涂喂料,利用等离子喷涂技术制备了镍基复合涂层。分析了喂料粒子物理性能及涂层的微观组织结构。结果表明:造粒后的粉末球形度较好,流动性大为提高。造粒烧结处理过程中,随着温度增加,粉末的流动性和松装密度均提高。经800℃热处理烧结后形貌圆整光滑,密实,平均粒径为32.92μm,松装密度为1.37g/cm^3,流动性为12.18s/50g,适合用作热喷涂喂料。制备的涂层为典型的层状结构,厚度约为320μm。涂层总体比较致密,局部存在孔洞,涂层孔隙率约3.6%。所含物相为NiCr、Ni3Al、NiAl、Ag,BaF2、CaF2等相,喷涂过程中未见新物相生成。

The high-energy ball-milled nickel-based alloy with silver and fluoride eutectic composite powders were used as raw materials to prepare thermal spray materials with particle size of 20~110μm by spray drying and sintering technology. Nickel-based composite coating was prepared by plasma spraying technology. The physical properties of the feed particles and the microstructure of the coating were analyzed. The results show that the powder after granulation has good sphericity and the fluidity. As the temperature increases during the granulation and sintering process, the fluidity and bulk density increased. After heat treatment at 800℃, the morphology of powder are round and smooth, with the average particle size of bulk density of 1.37 g/cm^3, and fluidity of 12.18 s/50 g, respectively, which is suitable for thermal spray feeding. As-coating with typical layered structure and the thickness of it is about 320μm. The porosity of the coating is about 3.6%. The phase contained is NiCr, Ni3Al, NiAl, Ag, BaF2 and CaF2, etc. No new phase is formed during the spraying process.