梯度过渡复相陶瓷涂层的制备及其耐磨性能研究

Study on Preparation and Wear Resistance of Gradient Transition Ceramic Coatings

采用幂函数分布形式设计梯度过渡涂层,以Ti-B_4C-C团聚粉和Ni-Al自粘结复合粉的混合物为自蔓延反应火焰喷涂体系,在45号钢基体表面制备了Ti(C_x,N_y)-TiB_2和Ni_mAl_n梯度过渡的复相陶瓷涂层,研究了梯度过渡涂层的组织特点与耐磨性能。研究表明,当梯度指数为1,涂层按6层设计时,涂层为典型的多相非均质结构。Ti(C_x,N_y)-TiB_2复相陶瓷与Ni_mAl_n金属间化合物实现了沿涂层厚度方向的梯度过渡连接。梯度过渡陶瓷涂层的耐磨性是普通45号钢耐磨性的14倍,涂层磨损失效过程受粘着磨损与磨粒磨损共同作用,失效过程中陶瓷相的剥落是涂层磨损的关键环节,涂层中的粘接相、氧化物相和孔隙对涂层磨损有重要影响。

Using Ti-B4C-C and Ni-A1 mixed powders as SHS reactive flame sprayed system, Ti（Cx,Ny）-TiB2-NimA1n gradient transition coatings were prepared on the 45# metal substrate adopting the design of power function distribution. The structure and wear resistance of the coatings were analyzed and studied. It is showed that when the gradient index is 1 and the coating is designed to be 6 layers, the coatings show the typical multiphase heterogeneous structure, which is composed of Ti（Cx,Ny）, TiC, TiN, TiB2 ceramic phase and NimA1n intermetallics. The gradient transition join from Ti（Cx,Ny）-TiB2 to NimA1n has been achieved along the thickness orientation. The wear resistance of the coating is 14 times of that of the 45# steel. The failure process is controlled by both adhesion abrasion mechanism and grinding particulate abrasion mechanism. The erosion of the ceramic phase during the failure process is the key part of the abrasion of the coatings. The joining phases, oxide phase and pores of the coatings have the important influence on the abrasion of the coatings.