【作者】 从东锋；

【导师】 杜晓东；

【作者基本信息】 合肥工业大学 ， 材料学， 2009， 硕士

【摘要】 本文采用改进的电弧喷涂技术,以低碳钢为粘结剂,在45#钢表面喷涂WC-钢复合喷涂层,而后又使用氩弧重熔工艺对喷涂层重熔,制备了WC-钢复合熔覆层。利用金相光学显微镜、场发射扫描电镜、能谱仪、X射线衍射仪等研究手段分析研究了WC-钢复合喷涂层和WC-钢复合熔覆层的微观组织、结构以及涂层结合区的组织特征。利用显微硬度计测量了喷涂层和熔覆层的硬度分析了熔覆层显微硬度变化。在MM-200型滑动磨损试验机上,对WC-钢复合熔覆层进行室温下的干滑动摩擦磨损性能测试,借助于扫描电镜观察磨损试样磨面形貌,探讨其摩擦磨损机理。试验结果表明:本试验尝试使用的改进的电弧喷涂方法在实验室中使用是可行的,利用这套改进的设备制备了钢基-WC喷涂涂层,并且得到了不同WC含量的喷涂层;经氩弧重熔后,层片状组织消失、组织细小致密,缺陷消除,熔覆层与基体之间过渡区显微硬度梯度较为平缓;喷涂层与基体之间主要是机械结合,而熔覆层与基体之间为良好的冶金结合;适量WC的加入可以形成大量细小的硬质相颗粒,从而提高了熔覆层的硬度与耐磨性;随着WC含量的增加,熔覆层的硬度会增加,但磨损性能先变好后变差;材料的耐磨性与WC的含量存在一定的对应关系,在提高材料耐磨性时,应考虑加入适量的WC;随着WC加入量的不同,复合涂层的磨损机制也有所不同:含10%WC的熔覆层磨损机制主要以粘着磨损带有微切削,含15%WC的熔覆层磨损机制以较为严重的微切削为主,含20%WC的熔覆层磨损机制主要为微切削和轻微剥落,含25%WC的熔覆层磨损机制主要为剥落。更多还原

【Abstract】 WC composite wear-resistant coating were coated on the surface of 45# steel by means of the improved arc spraying technology, and then remelted by argon shielded arc remelting technology.The microstructure of the composite coating was investigated by means of metallographic microscope, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The microhardness of composite coatings was measured by the microhardness instrument. And changes in microhardness of the cladding layer were analyzed.The wear resistance of the composite was tested by an MM-200 friction wear testing machine under unlubricated condition. The friction surface morphology was observed by means of scanning electron microscopy (SEM), and the wear mechanism was investigated.The results show that the method of the improved arc spraying technology feasible in laboratory. Some WC composite coating samples with different WC content were prepared. The microstructures of composite coatings after argon shielded arc remelted are more homogeneous and refine than WC-steel composite coatings after arc sprayed. And in the coatings, the lamellar character of the microstructure disappeared, defects eliminated, the cladding layer and the substrate transition zone between the relatively has a gentle microhardness gradient. The composite coatings are mechanically bond after arc spraying, but metallurgical bond after argon shielded arc remelted to the base metal. The hardness and wear resistance of the WC composite wear-resistant coat can be greatly improved as a result of the generation of amounts of finer particles with appropriate WC content. As the WC content increased, the hardness of the coating will increase, but the wear properties to deteriorate after the first changed for the better. There is a best content of WC in WC-composite coating in order to improve wear resistance of materials. There are different wear mechanisms, with different WC content in composite coating. The dominant wear mechanism is adhesion and slight cutting for that with 10wt%WC content, heavy cutting for the clad with 15wt%WC content, slight cutting and spalling with 20wt%WC content, and spalling with 25wt%WC content.更多还原