Diamond Coatings on Cutting Tools

用于加工许多难加工材料，例如 高硅铝硅合金和复合材料， 用高压（50千巴）制造的多晶金刚石工具 - 高温（1500 ℃）（HP-HT）工艺。 这些工具 由于加工和精加工的高成本， 并且需要替代的工具材料。 低压 化学气相沉积（CVD）金刚石合成，相反， 相对简单和便宜，因此提供了一个潜在的 生产金刚石涂层的切削工具。 这个项目的主要目标是发展科学 用于在各种切削工具上强粘附金刚石涂层的基底 材料，包括硬质合金（涂层和未涂层）和 陶瓷（氮化硅和SiAlON）的四个激活CVD 金刚石合成技术，即燃烧合成， 微波CVD、热灯丝CVD和激光辅助CVD， 重点放在前两个。 每一个的条件 活化CVD金刚石涂层工艺将被优化， 在给定刀具材料的基础上， 厚度和形态。 这些工具的特点是： 光学和扫描电子显微镜和拉曼光谱。 他们将在加工不同的工作材料进行评估， 以切割速度和切割长度为变量。 各种表面 包括表面蚀刻的处理、不同的表面 精加工条件，基材的表面层间涂层 将被考虑。 刀具磨损机制、刀具寿命和光洁度 将与金刚石涂层刀具的工作材料进行比较 与未涂覆的工具和/或多晶金刚石相比 工具.

For machining many difficult-to-machine materials, such as high silicon aluminum-silicon alloys and composites, polycrystalline diamond tools made by the high pressure (50 kbars) -- high temperature (1500 C) (HP-HT) process are used. These tools are expensive because of the high cost of processing and finishing and need exists for an alternate tool material. The low pressure chemical vapor desposition (CVD) diamond synthesis, in contrast, is relatively simple and inexpensive, thus offering a potential for producing diamond coated cutting tools. The primary goal of this project is to develop the science base for strongly adherent diamond coatings on various cutting tool materials, including, cemented carbide (coated and uncoated) and ceramics (silicon nitride and SiAION) by the four activated CVD diamond synthesis techniques, namely, combustion synthesis, microwave CVD, hot filament CVD, and laser assisted CVD with emphasis on the first two. The conditions for each of the activated CVD diamond coating processes will be optimized for a given tool material based on good metallurgical coating, its thickness and morphology. These tools will be characterized by optical and scanning electron microscopy, and Raman spectroscopy. They will be evaluated in machining different work materials with the cutting speed and length of cut as variables. Various surface treatments including etching of the surface, different surface finishing conditions, surface interlayer coatings for the substrate will be considered. Tool wear mechanisms, tool life, and finish of the work material with diamond coated tools will be compared with that of the uncoated tools and/or polycrystalline diamond tools.