PDC材料烧结过程中钴在金刚石层中的扩散熔渗迁移机制

 讨论了PDC材料烧结过程中钴在金刚石层中的固相扩散、钴液熔渗、两次钴高浓度峰的“波浪”式迁移过程中的运动规律及其作用机制，并根据实验观测的数据进行了有关计算。结果表明：在5.8 GPa、1 300 ℃条件下，钴的扩散系数D≈1.6×10^-7 cm²/s，是一般常压及相同温度条件下钴固相扩散系数（3×10^-10 cm²/s）和相同压力条件下钴的液相扩散系数（5×10^-5 cm²/s）的中间值；对于粒度W≥10 μm的金刚石烧结体系，钴液熔渗作用时间非常短暂，略大于0.5 s，而对于W≤1 μm的超细金刚石烧结体系而言，钴熔渗作用时间为28 s，比粒度W≥10 μm的金刚石烧结要长得多；两次钴高浓度峰的迁移速度分别约为50 μm/s和100 μm/s。

Diffusion and Infiltration Mechanisms of Cobalt through Diamond Layer during the Sintering of Polycrystalline Diamond Compacts

The mechanisms of solid cobalt diffusion, molten cobalt infiltration and two wave-like cobalt peaks movement through diamond layer during the sintering process were discussed theoretically according to the experiment data. Results show that the solid cobalt diffusion coefficient under 5.8 GPa and at 1 300 ℃ is about 1.6×10^-7 cm²/s, which is almost the mean value between the solid cobalt diffusion coefficient (3×10^-10 cm²/s) at the same temperature under atmospheric pressure and the liquid cobalt diffusion coefficient (5×10^-5 cm²/s) under 5.8 GPa and at 1 300 ℃. It also shows that the infiltration time of molten cobalt through diamond layer for diamond grain size 10 μm and 1 μm are about 0.5 s and 28 s respectively, and the moving velocity of the two wave-like cobalt peaks were about 50 μm/s and 100 μm/s, respectively.