氮弧熔覆TiCN/Fe金属陶瓷涂层对农业刀具耐磨性的影响

    Influence of TiCN/Fe metal ceramic coating by reaction nitrogen arc cladding on wear resistance of agricultural tools

    • 摘要: 针对农业刀具易磨损、失效频繁的现状,采用TXⅡ500型TIG焊机,以工业纯氮作为反应气体和保护气体,利用反应氮弧熔覆技术在表面预涂工业钛粉和石墨粉的Q235试件上成功制备了TiCN/Fe金属陶瓷复合涂层。利用扫描电镜、XRD射线衍射仪、显微硬度计着重分析了熔覆速度对涂层形貌、涂层物相、涂层显微硬度的影响,并与农业刀具进行了耐磨对比试验。结果表明:熔覆速度较小时涂层表面成形良好,但涂层中TiCN含量低、涂层硬度小;随着熔覆速度的增加,涂层表面成形变差,但涂层硬度增大。涂层近表层显微硬度最高可达HV0.5 1089,约是Q235硬度的3倍多,与农业刀具常用材料65 Mn相比,磨损量仅为65 Mn的1/2,涂层有较好的耐磨性。

       

      Abstract: Abstract: There is a current problem that agricultural tools easily get worn and frequently lose effectiveness. In order to solve this problem, the TiCN/Fe metal ceramic coating had been successfully prepared on a Q235 steel specimen surface by a reaction nitrogen arc cladding technique with a TXⅡ500 argon arc welding machine. In the coating preparation, the industrial titanium powder and the graphite powder (300 mesh, a purity of 98%) are mixed at the ratio of 47.9:12 in weight with 6 hours through the DQM type planetary ball mill, and precoated on the specimen surface. The precoated thickness is 2±0.2 mm, and the industrial N2 (purity 99.999%) is used as a reaction and protection gas. The coating was prepared on the surface of a specimen based on the high temperature of the nitrogen arc which made the N2 and precoated powder react in the course of welding. Effects of cladding speed (1.5, 2.0, 3.0 mm/s) on morphology, phase, and microhardness of the TiCN/Fe coating were analyzed by means of a scanning electronic microscope (SEM), X-ray diffractometer (XRD), and microhardness gauge, and contrast tests of wear were done between agricultural tools and coating. The results showed that the surface of the coating can obtain good morphology when the cladding speed is 1.5 mm/s, but when the coating contains less TiCN and the microhardness of coating is low; with the increase of the cladding speed(such as 3.0 mm/s), the coating morphology is worse off, but the microhardness and wear resistance have been increased obviously. The microhardness on the coating surface could reach up to HV0.5 1089, about 3 times as much as Q235 microhardness. Contrasted with common agricultural tools material (65 Mn), the wear loss is only 1/2 times as 65Mn, and the coating wear resistance is better. The coating can be used on agricultural tools for improving the service life of tools.

       

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