超音速等离子喷涂YPSZ涂层的组织及耐磨性能

为了研制一种连铸结晶器耐高温耐磨材料,采用超音速等离子喷涂法在纯铜板上制备了氧化钇部分稳定的氧化锆(YPSZ)涂层.利用X射线衍射仪、扫描电镜、彩色3D激光显微镜和图形软件(Image-pro Plus3.0)对YPSZ涂层的微观组织进行表征,通过销盘式磨损仪在室温干摩擦条件下测试了涂层的耐磨性能及化学硬化对涂层耐磨性能的影响.研究发现YPSZ涂层完全由t’-ZrO₂相组成,其断口形貌由柱状晶和一定量的部分熔融颗粒组成,截面组织形态表现出较好的完整性,涂层孔隙率为1.2%,表面粗糙度为6.457μm.磨损实验表明化学硬化前YPSZ涂层与刚玉球对磨时的摩擦因数在0.5~0.6之间,平均磨痕宽度为3638.8μm,磨损体积为1.25508×10^-2mm³,磨损机制为脆性断裂导致的磨粒磨损;化学硬化后YPSZ涂层的磨痕宽度和磨损体积均有大幅降低,脆断程度也更轻,其磨损性能得到极大改善.

Microstructure and wear resistance of YPSZ coatings deposited by supersonic plasma spraying

In order to obtain a kind of high temperature-resistant and wear-resistant material for continuous casting molds, yttria partially stabilized zirconia (YPSZ) coatings were prepared on pure copper substrates by high-efficiency supersonic atmosphere plasma spraying (SAPS). The microstructure of the coatings was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), color 3D laser scanning microscopy and image software (Image-pro Plus). The wear resistance of the coatings and the effect of chemical hardening on the wear resistance were investigated through a pin-on-disk tribometer under dry friction at room temperature. It is found that the composition of the coatings is completely t'-ZrO₂ phase. The fracture microstructure is composed of columnar crystals and a small amount of partially melted particles. The cross-sectional morphology exhibits good integrity. The porosity and the surface roughness are 1.2% and 6.457 tim, respectively. Pin-on-disk test against corundum show that the friction coefficient, average wear width and wear volume of the coatings before chemical hardening is 0.5 to 0.6, 3638.8 μm and 1.25508×10-2 mm3, respectively. The wear mechanism is abrasive wear resulting from brittle fracture. The wear resistance of the coating after chemistry hardening is greatly improved that the width and volume of wear reduce drastically and the degree of brittle fracture is lighter.