喷距对低温超音速火焰喷涂WC-10Co4Cr涂层性能的影响

发布时间：2019-02-17 15:51

【摘要】：以粒度为5~15μm的WC-10Co4Cr为热喷涂粉末,采用低温超音速火焰喷涂(LT-HVOF)技术制备WC-10Co4Cr涂层,并利用粒子收集技术研究喷距对涂层显微结构和性能的影响。采用扫描电子显微镜(SEM)、粗糙度测试仪和显微硬度仪分别对涂层的显微结构、粗糙度、硬度和韧性进行测试分析。实验结果表明:WC-10Co4Cr涂层的显微硬度(HV0.3)和致密度随着喷距的增大而降低,分别由喷距100 mm时的1 484.19和0.5%降低至喷距310 mm时的930.50和2.2%;涂层的结构和性能与粉末在焰流中的熔融状态和飞行速度相关,喷距在100~190 mm范围内粉末呈未熔化状态,220~310 mm范围内呈微熔化状态,粉末的飞行速度随喷距的增加呈下降趋势;粉末呈微熔化状态时断裂韧性与HVOF涂层相当且明显高于粉末呈未熔化状态的断裂韧性;优化的喷涂距离为220~280 mm,该段距离内可以获得涂层粗糙度约为2μm、孔隙率小于1%、显微硬度大于1 018(HV0.3)、断裂韧性大于3.323 1 MPa·m1/2的涂层。
[Abstract]:The WC-10Co4Cr coating was prepared by low temperature supersonic flame spraying (LT-HVOF) with 5 渭 m WC-10Co4Cr as thermal spraying powder. The effect of spray distance on the microstructure and properties of the coating was studied by particle collection technique. The microstructure, roughness, hardness and toughness of the coatings were measured and analyzed by scanning electron microscope (SEM) (SEM), roughness tester and microhardness tester respectively. The experimental results show that the microhardness (HV0.3) and density of WC-10Co4Cr coating decrease with the increase of spray distance, from 1 484.19 and 0.5% of the spray distance of 100 mm to 930.50 and 2.2% of the spray distance of 310 mm, respectively. The structure and properties of the coating are related to the melting state and the flying speed of the powder in the flame flow. The powder shows an unmelted state in the range of 100 ~ 190 mm and a slightly melted state in the range of 220 mm. The flying velocity of the powder decreases with the increase of the jet distance. The fracture toughness of the powder is similar to that of the HVOF coating and is obviously higher than that of the powder in the unmelted state. The coating with roughness of about 2 渭 m, porosity of less than 1, microhardness greater than 1 018 (HV0.3) and fracture toughness of more than 3.323 1 MPa 1 / 2 can be obtained from the optimized spraying distance of 220 ~ 280 mm,.
【作者单位】：中南大学材料科学与工程学院;广州有色金属研究院;
【基金】：广东省高新技术产业化项目(2011B010400040) 广州市科技计划项目(2013Y2-00113)~~
【分类号】：TG174.4

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