MPCVD单晶金刚石高温退火的力学性能研究

Study on Mechanical Properties of MPCVD Single-Crystal Diamond by Annealing at High Temperature

摘要: 为了改善单晶金刚石的力学性能，增强单晶金刚石刀具的实用性和使用寿命。本文通过对MPCVD单晶金刚石进行高温常压退火和等离子退火两种方式的实验研究，期望能够提升已经生长的单晶金刚石的力学性能。通过研究发现经过高温退火的单晶金刚石晶体质量和力学性能均有改善，但当达到一定的温度和时间时，随着处理温度和时间的升高其晶体质量和力学性能会开始有所下降。这是因为一定的高温退火可以有效减少金刚石晶体中的缺陷，消除内应力，从而改善晶体质量和力学性能，但当超过一定的退火温度或时间时，会出现新的缺陷，从而导致晶体质量和力学性能变差。通过本文实验数据对比，发现经过高温常压退火1400℃，保温4 h退火后的单晶金刚石晶体质量和力学性能最好。

Abstract: To enhance the mechanical properties of single-crystal diamond and augment the practicability and service life of single-crystal diamond tools, this paper undertakes experimental investigations on two annealing methods, namely high-temperature and normal-pressure annealing and plasma annealing of MPCVD single-crystal diamond, with the expectation of elevating the mechanical properties of the grown single-crystal diamond. The research reveals that both the crystal quality and mechanical properties of the single-crystal diamond subjected to high-temperature annealing are improved. However, when a certain temperature and time are reached, the crystal quality and mechanical properties start to decline with the increase in processing temperature and time. This is because a certain high-temperature annealing can effectively reduce the defects in the diamond crystal and eliminate the internal stress, thereby improving the crystal quality and mechanical properties. But when the annealing temperature or time exceeds a certain limit, new defects will emerge, leading to the deterioration of the crystal quality and mechanical properties. Through the comparison of the experimental data in this paper, it is found that the crystal quality and mechanical properties of the single-crystal diamond after high-temperature and normal-pressure annealing at 1400˚C for 4 hours are the optimum.