天然金刚石晶体的真空热化学腐蚀工艺

Thermo-chemical erosion of natural diamond crystals under vacuum atmosphere

摘要:

为了给天然金刚石刀具的使用寿命延长提供一种全新的技术方法,提出了基于纳米氧化铜的真空热化学腐蚀新工艺,用于后处理机械刃磨工艺加工的天然金刚石晶体．实验结果表明,当真空环境温度为100 ℃时,天然金刚石晶体表面受损碳原子和纳米氧化铜发生氧化、还原反应．随着腐蚀时间的增加,天然金刚石晶体的表面粗糙度缓慢降低,呈现微弱的平坦化趋势．当真空环境温度为200 ℃时,2 h的热处理时间为最佳．此过程中天然金刚石晶体表面受损碳原子和纳米氧化铜发生氧化、还原反应,同时伴随受损碳原子的退火修复作用,因此30 nm压痕深度下的表面微硬度和弹性模量值达到最大．随着腐蚀时间增加,表面微硬度和弹性模量反而下降．

Abstract:

To provide a novel technique to prolong the service life of diamond cutting tools, a thermo-chemical erosion method by using nano-scale copper oxide under vacuum atmosphere was proposed to perform the post-treatment of natural diamond crystals, which had been pre-polished with mechanical lapping procedure. As indicated in the experiments, when the temperature under vacuum atmosphere was 100 ℃, the oxidation and deoxidation appeared between the damaged diamond carbon atoms on the topmost surface layer and the copper oxide powder. The surface roughness of natural diamond crystal declined slowly with the increment of erosion time, i.e. generating a weak planarization tendency. When the vacuum atmosphere temperature was 200 ℃, two hours erosion time was considered as the optimal configuration. At 30 nm indentation depth, the micro-hardness and elastic ratio of the eroded diamond crystal surface reached the maximal value. If the erosion time was larger than two hours, the micro-hardness and elastic ratio declined. 