合成聚晶金刚石过程的颗粒冷压破碎

Cold compaction and crushing of diamond powders during the sintering of polycrystalline diamond

为提升聚晶金刚石的致密度,研究在初装、冷等静压后以及六面顶压机内等不同压力条件下,不同金刚石粉体粒径和配比在加压前后的粉体密度、粒径分布及重排微观结构变化,发现金刚石粉体的变化规律。合成过程包括初装料的无序排列到220 MPa等静压后的细颗粒填充孔隙与重排,再到超高压力下大颗粒被挤压破碎,孔隙被逐步填充。由于细颗粒的缓冲效应,大颗粒G_(20~30)在双粒径配方G_(2~4)和G_(20~30)中比在单一粒径G_(20~30)配方中破碎更少,更有利于提升金刚石粉体堆积密度。

To improve the density of polycrystalline diamond,a study was conducted to investigate the changes in diamond powder under different pressure conditions,including initial loading,cold isostatic pressing,and six-sided die pressing.The study focused on the particle size distribution,powder density,and microstructural rearrangement before and after applying pressure to different diamond powder sizes and ratios.The process involved the initial random arrangement of particles,followed by the filling of fine particles into voids and rearrangement at 220 MPa during cold isostatic pressing.Subsequently,under ultra-high pressure,large particles(G_(20~30))were crushed and gradually filled the voids.The buffering effect of fine particles resulted in fewer fractures in the dual particle size formula(G_(2~4)and G_(20~30))compared to the single particle size formula(G_(20~30)),which facilitated higher stacking density of the diamond powder.These findings provide valuable data support for optimizing the particle size and ratio design of diamond powders for the high-temperature high-pressure(HPHT)synthesis of high-performance polycrystalline diamond composite.