大气等离子喷涂TiB2-TiC-Co涂层的组织与性能

利用Co-Ti-B4C自蔓延体系合成TiB2-TiC-Co复合陶瓷粉末，并结合大气等离子喷涂技术在Q235 钢基体表面制备TiB2-TiC-Co陶瓷涂层，研究了自蔓延产物和涂层的相组成、显微组织，以及涂层的结合强度和抗磨损性能。结果表明：Co-Ti-B4C体系自蔓延产物的物相中，除了少量剩余的NaCl添加剂衍射峰外，主要由TiB2和TiC陶瓷相的强衍射峰组成；产物断面中，两相陶瓷颗粒细小。随Co含量增加，TiB2-TiC-Co涂层表面盘状组织增多，表面逐渐平滑，截面涂层厚度均匀，组织致密性逐渐增加；结合强度和耐滑动磨损性能呈先升高后降低的变化趋势。Co含量为10wt.%时，涂层的结合强度和耐滑动磨损性能最好，涂层的滑动磨损机制主要为粘着磨损和层状剥落磨损。

Microstructure and Properties of TiB2-TiC-Co Coatings by Atmospheric Plasma Spraying

TiB2-TiC-Co composite powders were successfully synthesized from a Co-Ti-B4C system by self-propagating high-temperature synthesis (SHS), and TiB2-TiC-Co cermet coatings were produced on a Q235 steel substrate by atmospheric plasma spraying (APS). Phase composition and microstructure of the SHS products and APS coatings were investigated, and bonding strength and wear resistance of the coatings were examined. The results show that the phase of Co-Ti-B4C SHS products mainly consists of strong TiB2 and TiC diffraction peaks in addition to the diffraction peaks of a small amount of remained NaCl additive. Both TiB2 and TiC ceramic particles are fine. With the increase of Co content, the disk-like splats increase on the surface of TiB2-TiC-Co coating, and the surface becomes smooth gradually. The thickness of the coatings are uniform, and the densification is improved. The bonding strength and sliding wear resistance present the trend of first increasing and then decreasing. The bonding strength and sliding wear resistance of the coating reaches optimum value with 10 wt.% Co content. The wear mechanism of the coating is mainly adhesive wear and lamellar peeling wear.