Ksiazek Marzanna, Nejman Ilona, Boron Lukasz
Department of Non-Ferrous Metals, AGH University of Science and Technology, 30 Mickiewicza Ave., 30-059 Cracow, Poland.
Łukasiewicz Research Network-Cracow Technology Institute, 73 Zakopianska St., 30-418 Cracow, Poland.
Materials (Basel). 2021 Jun 14;14(12):3282. doi: 10.3390/ma14123282.
Recent work indicates that the high-velocity oxy-fuel (HVOF) thermal spraying WC-Co coatings have been used to enhance the wear resistance of various engineering components in a variety of industrial environments. In the present work, WC-Co powder, containing Cr particles in an amount of 10%, was deposited on ductile cast iron with the HVOF thermal spray coating technique. An investigation was conducted to determine the role of Cr particles in the WC-Co coating produced with the HVOF technique on microstructure, mechanical, and wear properties in a system of type: WC-Co coating/ductile cast iron. The microstructure of the HVOF-sprayed WC-Co + Cr coating was characterised by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy (EDS). The analysis of the microstructure showed the formation of a coating with low porosity, compact structure, and good adhesion to the substrate with a typical lamellar structure composed of fine molten Cr particles and finely fragmented WC grains embedded in a Co matrix, reaching the size of nanocrystalline. The scratch test was applied for the analysis of the adhesion of coatings to the substrate. The erosion behaviour and mechanism of material removal was studied and discussed based on microstructural examinations. Moreover, the results were discussed in relation to the bending strength test, including cracks and delamination in the system of the WC-Co + Cr/ductile cast iron, as microhardness and erosion resistance of the coating. It was found that the addition of Cr particles to the WC-Co powder, which causes hardening of the binder phase is a key influence on increased mechanical and wear properties in the studied system. Additionally, due to the construction of nanostructured coatings, suitable proportion of hard and soft phases, the technique sprayed HVOF coatings have advantageous properties such as high density and good slurry erosion resistance.
近期研究表明，高速氧燃料（HVOF）热喷涂WC-Co涂层已被用于提高各种工业环境中各类工程部件的耐磨性。在本研究中，采用HVOF热喷涂技术将含10% Cr颗粒的WC-Co粉末沉积在球墨铸铁上。开展了一项研究，以确定WC-Co涂层中Cr颗粒在WC-Co涂层/球墨铸铁体系中对涂层微观结构、力学性能和耐磨性能的作用。通过光学显微镜、X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和能量色散X射线光谱（EDS）对HVOF喷涂的WC-Co + Cr涂层的微观结构进行了表征。微观结构分析表明，形成了一种低孔隙率、致密结构且与基体具有良好附着力的涂层，其典型的层状结构由细小的熔融Cr颗粒和嵌入Co基体中的细碎WC晶粒组成，达到了纳米晶尺寸。采用划痕试验分析涂层与基体的附着力。基于微观结构检查，对材料去除的冲蚀行为和机制进行了研究和讨论。此外，还结合弯曲强度试验对结果进行了讨论，包括WC-Co + Cr/球墨铸铁体系中的裂纹和分层，以及涂层的显微硬度和耐冲蚀性。研究发现，向WC-Co粉末中添加Cr颗粒会导致粘结相硬化，这是影响所研究体系中机械性能和耐磨性能提高的关键因素。此外，由于纳米结构涂层的构建、软硬相的合适比例，HVOF喷涂技术制备的涂层具有诸如高密度和良好的浆体冲蚀抗性等优异性能。
