超细晶粒金刚石涂层钻头的制备与实验

以钻头为例，根据其复杂形状衬底的特点，研究了一种新的化学预处理方法，并在传统化学气相沉积(CVD)工艺的基础上发展了一种新的CVD分阶段沉积法．实验以氢气和丙酮为原料，采用电子增强热丝CVD法在复杂形状硬质合金(WC-Co)钻头最外表面复合涂覆一层超细晶粒金刚石薄膜，并对碳化硅颗粒增强铝基复合材料进行了钻削实验．结果表明，所制备的超细晶粒金刚石涂层薄膜表面光滑，晶粒尺寸细小，涂层质量良好．提高和改善了涂层刀具的耐用度和切削性能．

Fabrications and Cutting Tests of Ultrafine Grain Diamond Coated Drills

Ultrafine grain diamond thin films were deposited on the WC-Co-based drills by electron-aided hot filament chemical vapor deposition (EACVD). Considering the fact that the drill is of very complex geometrical characteristics, which brings much difficulties to its pretreatment process, a new multiple chemical pretreatment technology including microwave oxidation, reaction in alkaline solution and cleaning by ultrasonic treatment in acid solution was developed. The effects on the diamond adhesion strength, nucleation and surface morphology were investigated. At the same time, a special EACVD process called varied parameters controlling model was developed. By this new model, ultrafine grain diamond film can overlap on the previously deposited diamond film consisted of large facet grains. The high quality diamond-coated drills with good adhesive strength and smooth roughness can be obtained. The cutting performances of the diamond-coated drills were investigated by drilling SiC particles reinforced aluminum matrix composites. The significant wear resistance and good chip evacuation capability lead to the reduced torque and thrust force, which improves the cutting performance of this kind of drill.