CAJ | 학술논문

针对农机作业中触土刀具易磨损、失效频繁、寿命低、消耗成本高等现状，研究开发了金属表面熔覆陶瓷涂层工艺。采用反应等离子熔覆技术，在Q235B钢表面制备了Ti(C,N)-WC增强Ni60A基复合陶瓷涂层。利用扫描电镜、能谱仪、X射线衍射仪、显微硬度计、金相显微镜等对复合熔覆层的微观结构及强质硬化相的成分、组织、性能进行了分析。研究结果表明：预涂敷层中的钛（Ti）粉、石墨粉、氮化钛（TiN）粉在等离子熔覆过程中原位合成了颗粒状新生相 Ti(C,N)，且均匀弥散分布在熔覆层中，形成了主要由硬质相、包覆相、粘结相组成的芯-环结构；涂层平均硬度达 HV0.51750，最高可达 HV0.52040；涂层的磨损机理主要为磨粒磨损，与基体相比，有较好的硬度和耐磨性能，以期为农机刀具材料强化提供参考。
침대농궤작업중촉토도구역마손、실효빈번、수명저、소모성본고등현상，연구개발료금속표면용복도자도층공예。채용반응등리자용복기술，재Q235B강표면제비료Ti(C,N)-WC증강Ni60A기복합도자도층。이용소묘전경、능보의、X사선연사의、현미경도계、금상현미경등대복합용복층적미관결구급강질경화상적성분、조직、성능진행료분석。연구결과표명：예도부층중적태（Ti）분、석묵분、담화태（TiN）분재등리자용복과정중원위합성료과립상신생상 Ti(C,N)，차균균미산분포재용복층중，형성료주요유경질상、포복상、점결상조성적심-배결구；도층평균경도체 HV0.51750，최고가체 HV0.52040；도층적마손궤리주요위마립마손，여기체상비，유교호적경도화내마성능，이기위농궤도구재료강화제공삼고。
The agricultural touching-cutter wears-out easily, fails frequently, has high costs and the service life is low. In order to solve these problems, a process of cladding ceramic coating on the metal surface is researched and developed against the agricultural mechanization situation. Using the DML-300 plasma welding machine, Ni60A based composite coating reinforced by in-situ synthesized Ti(C,N)-WC particulates was prepared on the surface of Q235B steel substrate by reactive plasma cladding technology. First, the titanium powder, graphite powder, TiN powder, WC powder and Ni60 powder was mixed 6 hours in the DQM planetary mill, the mass ratio was 28:7:15:12.5:37.5. The mixing powder was modulated into paste with the 504 glue as the adhesive. Then the mixing powder was put on the substrate of Q235B and the thickness was (2±0.5)mm, reserving 2-3 mm arc end. Finally, the specimen was placed in the electrothermal blowing dry box, heating up to 80℃. The plasma arc single channel was used to scan to clad, avoiding the thermal impact between each channel, during which the heat source was provided by the DML-300 plasma welding machine to melt and react between the depositing material components to synthesize composite ceramic coating in-situ. The plasma cladding technology parameters are: The scanning width of single channel is 4-5 mm; Working current is 200 A; Working voltage is 20 V; Argon is used as the shielding gas and the ion gas,the flow of them are 6-8 L/min, 0.6 L/min; Working distance is 4mm, Scanning speed is 150 mm/min. Composition, microstructure, organization and performance are analyzed by scanning electron microscope (SEM), energy disperse spectrometer (EDS), X-ray diffractometer (XRD), microhardness tester and metallurgical microscope. The results show that Ti powder, graphite powder, TiN powder of the pre-coated layer was synthesized in-situ granular new phase Ti(C,N) during the plasma cladding process. The new phase Ti(C,N) granules are uniformly dispersed in the cladding coating, and mainly form the core- ring structure composed of the hard phase, coated phase, and adhesive phase. Ti(C,N) and WC disperse uniformly in the Fe-Ni adhesive phase, Ti(C,N)-WC/Ni60A composite coating metallurgically combined with the substrate is prepared. Polygonal flake WC distributes in the cladding coating surface and the core-ring structure disperses among the adhesive phase of the subsurface. The surface hardness is bigger than the subsurface. The average hardness of the coating is HV0.51750, up to HV0.52040, and about 10 times of the microhardness of Q235B steel substrate. The strengthening mechanism of the cladding coating is both fine-grain strengthening and dispersion strengthening. The wear quantity of the cladding coating is about 1/6 of the new cutter material 65Mn steel. The wear mechanism of the cladding coating is mainly abrasive wear. There were not obvious existing furrows and the signs of wear and tear on the coating have a lower friction coefficient and an excellent dry sliding wear resistance. The plasma cladding Ti (C,N)-WC/Ni60A metal composite coating is not only suitable for operation under normal pressure (atmospheric pressure) with the excellent characteristics of the simple process, easy operation, low manufacturing costs and excellent performance of cladding layer, but also applies to wear-resistant strengthening treatment, repair and remanufacturing of agricultural touching-cutter.