聚晶金刚石复合片超高压烧结过程的实验研究

Sintering Process of Polycrystalline Diamond Compact under High Pressure

采用X射线衍射(XRD)分析、扫描电子显微镜(SEM)和能谱分析(EDX)等方法,对在压力5.6 GPa、温度1 460℃条件下,加热时间分别为2、3、4、6、8、10 min的聚晶金刚石复合片(PDC)样品进行了分析。结果表明:PDC的烧结经历了金刚石的石墨化过程,而且在烧结过程中金刚石层表面的XRD图谱出现了WC衍射峰,强度由弱到强,再由强到弱,直至消失;进一步的研究发现,PDC中助烧结剂Co的晶格常数因C和W原子的固溶会变大,并随PDC加热时间的延长出现一个峰值;从硬质合金基体扩散到金刚石层的Co由于扩散通道各异、所受阻力不同,使得其分布不均匀。

The polycrystalline diamond compact （PDC） samples sintered at 1 460 ℃, 5.6 GPa and at varied sintering time were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM） and EDX. In the XRD patterns, graphite （002） peak was found in the sample sintered for 40 s. It was also found that the WC （100） peaks in different samples change from weak to strong and then to weak, and finally disappear with the increase of the sinter time of PDC. Furthermore, the calculated results from the XRD data show that the magnitude of the cell parameter of the cobalt in the diamond layer of PDC increases with the sinter time due to the solution of the W or C. It was observed that the distribution of the cobalt diffusing from the substrate of WC is uneven.