原位生成TiC增强镍基梯度涂层的组织与性能

Microstructure and Properties of TiC-Reinforced Nickel-Based Gradient Coatings Generated in Situ

通过激光熔覆技术在H13钢表面原位生成TiC增强镍基单一涂层和梯度涂层,使用扫描电镜、能谱仪、X射线衍射仪、显微硬度计、万能摩擦磨损试验机对涂层的微观形貌、成分分布、物相组成、显微硬度和摩擦磨损性能进行对比分析。结果表明,单一涂层易出现宏观气孔、裂纹、与基体结合差等缺陷,而梯度涂层能够实现成分、组织性能的梯度变化,与基体形成良好的冶金结合;梯度涂层生成Fe-Cr、TiC等多种增强相,使钢表面硬度和耐磨性显著提高,平均硬度约为单一涂层的1.44倍、基体的2.58倍;梯度涂层的平均磨损量为单一涂层的45.6%、基体的32.4%;梯度涂层磨损机理主要是颗粒磨损和粘着磨损。

TiC-reinforced Ni-based single coatings and gradient coatings were generated in situ on the sur-face of H13 steel by laser cladding technology.The micromorphology,composition distribution,phase com-position,microhardness and frictional wear resistance of the coatings were analyzed and compared by scan-ning electron microscope,energy spectrometer,X-ray diffractometer,microhardness tester and universal friction and wear testing machine.The results show that the single coating is prone to macroscopic pores,cracks,poor bonding with the matrix and other defects,while the gradient coating can realize the gradient change of composition,microstructure and properties,and form a good metallurgical bonding with the ma-trix.Fe-Cr,TiC and other reinforcing phases generate in the gradient coating,which significantly improves the surface hardness and wear resistance of the steel.The average hardness of the gradient coating is about 1.44 times that of the single coating and about 2.58 times that of the matrix.The average wear loss of the gradient coating is 45.6%of that of single coating and 32.4%of that of the matrix.The wear mechanism of the gradient coating is mainly abrasive wear and adhesive wear.