Microstructures and thermal damage mechanisms of sintered polycrystalline diamond compact annealing under ambient air and vacuum conditions
Microstructures and thermal damage mechanisms of sintered polycrystalline diamond compact annealing under ambient air and vacuum conditions
复制标题
环境空气和真空条件下烧结聚晶金刚石复合片退火的显微组织和热损伤机制
DOI：
10.1016/j.ijrmhm.2015.07.024
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发表时间：
2016-01-01
影响因子：
3.6
通讯作者：
Wang, Chengbiao
中科院分区：
文献类型：
--
作者：
Li, Jiansheng;Yue, Wen;Wang, Chengbiao
在环境空气和真空中，在高达1000℃的温度下，研究了烧结聚晶金刚石复合片（PDC）的微观结构和热损伤机制。通过白光干涉仪、X射线衍射（XRD）、拉曼光谱和扫描电子显微镜（SEM）对退火后的PDC的微观结构和成分进行了表征。结果表明，在200℃的环境空气和真空中，PCD层（PDC表面）的表面形态没有观察到明显的变化。 500℃退火后，PDC表面出现大量剥落坑，应力诱导剥落机制是环境空气和真空中的主要热损伤机制。当温度高达800℃时，环境空气中退火的PDC表面受到石墨化、氧化和应力诱导微裂纹等混合热损伤机制的严重破坏。而真空中的热损伤机制与500℃时几乎相同。在900℃时，由于环境空气中的广泛石墨化和氧化，退火后的PDC表面仅含有Co3O4的枝晶相。在真空环境下，PDC表面出现许多裂纹，裂纹附近有一些细小的金刚石晶粒剥落，这表明热损伤机制包括应力诱导裂纹和金刚石与Co相不同热膨胀系数引起的剥落机制。与900℃相比，在真空中1000℃时，由于Co的扩散不均匀，热损伤程度降低。 (C) 2015 Elsevier Ltd. 版权所有。
The microstructures and thermal damage mechanisms of sintered polycrystalline diamond compact (PDC) were studied in ambient air and vacuum at the temperature up to 1000 degrees C. The microstructures and compositions of the annealed PDC were characterized by white light interferometer, X-ray diffractometry (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The results showed that no visible change in the morphologies of surface of PCD layers (PDC surfaces) was observed at 200 degrees C both in ambient air and vacuum. After annealing at 500 degrees C, numbers of spalling pits appeared on the PDC surface, and the stress-induced spall mechanism was the dominant thermal damage mechanism in ambient air and vacuum. With the temperature up to 800 degrees C, the annealed PDC surface in ambient air was seriously damaged with a mixed thermal damage mechanism such as graphitization, oxidation and stress-induced micro-cracks. Whereas, the thermal damage mechanism in vacuum was nearly the same as that at 500 degrees C. At 900 degrees C, only a dendritic phase of Co3O4 was contained on the annealed PDC surface due to extensive graphitization and oxidation in ambient air. When it comes to vacuum environment, many cracks were observed on the PDC surface and some fine diamond grains near the cracks spalled, which demonstrated that the thermal damage mechanisms consisted of stress-induced crack and spall mechanisms caused by the different thermal expansion coefficients between the diamond and Co phase. Compared with that at 900 degrees C, the degree of thermal damage reduced at 1000 degrees C in vacuum because of the diffusion of unevenly distributed Co. (C) 2015 Elsevier Ltd. All rights reserved.