纳米结构金属陶瓷(n-WC/Co)涂层材料精密磨削的试验研究

EXPERIMENTAL STUDY ON THE PRECISION GRINDING OF NANOSTRUCTURED CERAMIC COATINGS

本文对纳米结构金属陶瓷(n—WC/Co)涂层材料在金刚石砂轮精密磨削过程中的磨削力进行了较详细的试验研究。对常规结构金属陶瓷(c—WC/Co)和n—WC/Co涂层材料的磨削力作了对比磨削试验,分析了磨削工艺参数如砂轮磨削深度、工件进给速度、金刚石砂轮结合剂类型和磨粒尺寸以及被磨试件材料特性等对磨削力的影响,结合被磨试件表面的扫描电镜(SEM)的观察,分析了n—WC/Co涂层材料磨削的材料去除机理。研究结果表明:在相同磨削条件下,纳米结构陶瓷涂层的磨削力始终高于常规结构陶瓷涂层的磨削力;在其它磨削条件相同的情况下,用金属结合剂砂轮磨削工件所需的磨削力要比树脂结合剂砂轮、陶瓷结合剂砂轮所需的磨削力大些,磨粒尺寸小的砂轮磨削工件所需的总磨削力要比磨粒尺寸大的砂轮所需的磨削力大些,磨削力随砂轮磨削深度、工件进给速度的增加而增大;一般情况下,n—WC/Co涂层材料精密磨削过程的材料去除机理中,占主导方式的是塑性成形的材料去除方式。

In this paper, the grinding force during precision grinding of nanostnictured ceramic (n- WC/Co) coatings with diamond grinding wheel was studied. The grinding force of conventional ceramic (c - \vC/Co) coatings was also studied experimentally compared to nanostructured ceramic coatings. The effect of grinding process parameters such as grinding depth, workpiece feedrate, bond type and grit size of diamond grinding wheel as well as the properties of ground materials upon the grinding forces were analysed in detail. Combined with SEM observations of the ground surface, the material removal mechanism in the grinding of nanostructured ceramic (n - WC/ Co) coatings was analysed. Trie results showed that the grinding forces for nanostructured ceramic coatings were constandv higher than that for conventional ceramic coatings under the same grinding conditions. Metal bond and smaller grit size led to higher grinding force than resin and vitrified bond and big grit size. The grinding force increased with the increase of depth of cut or feedrate. Generally, the material removal mechanism of ductile flow was dominant during the precision grinding of nanostructured ceramic (n - WC/Co) coatings.