Cobalt was an indispensable role in the damage of a PDC cutter due to its inevitable adverse thermal effect like thermal catalysis, thermal expansion and thermal oxidation in the welding and drilling process, while the quantitative studies on its serial thermal damage effect were still seldom reported. In order to understand the damage mechanism of a PDC cutter and therefore design better products, it was quite necessary to study the roles of cobalt in the PDC cutter by a quantitative means. In present study, the total cobalt content of the PCD layer of polycrystalline diamond compacts were adjusted by blending different amount of microsized cobalt powder in the mixed diamond grains and the infiltrated cobalt from the cemented carbide cylinder during the HTHP sintering process. The sintered PDC cutters were examined by XRD, SEM, EDX, vertical lathe tests, and impact tests, and it was found that the abrasive ratios of the fabricated PDC cutters were strongly dependent on the cobalt content of sintered diamond layers. The PDC cutter without adding cobalt powder exhibited the best resistance to the abrasion, while the PDC cutters sintered by adding 4% mass of cobalt powder demonstrated the worst abrasive ratio, which was the direct proof confirming that by decreasing the content of residual cobalt in the PCD layer the resistance of the PDC cutter to the abrasion would be improved significantly. A non-destructive characterization method was adopted based on the statistical calculation was proposed by using Matlab and Image-J software to quantitatively explore the relationship between the cobalt content as well as the average size of residual cobalt in the PCD layer and the abrasion performance, which opened a new technical route for the disclosure of cobalt-dependent abrasion resistance for the PDC cutter analysis. Moreover, a cobalt-rich narrow zone was found to appear in the interface of PCD/cemented carbide, which was deduced to be the main reason to cause the delamination of PCD layer from the cemented carbide. It was also interesting to find that the percentage of added cobalt powders seemed no adverse effect on the impact performance of the PDC cutters. The conclusion of present study about the cobalt role in the PDC performance was quite good for understanding the PDC damage modes and helped for the better design and fabrication of PDC.

钴在PDC刀具的损坏中起着不可或缺的作用，因为它在焊接和钻孔过程中不可避免地会产生不利的热效应，如热催化，热膨胀和热氧化，而有关其连续热损伤效应的定量研究仍很少报道。为了了解PDC刀具的损坏机理并因此设计更好的产品，非常有必要通过定量方法研究PDC刀具中钴的作用。在本研究中，通过在HTHP烧结过程中，将混合金刚石颗粒中不同量的微细钴粉与渗入的硬质合金圆柱体中渗入的钴混合，来调节多晶金刚石复合片PCD层的总钴含量。用XRD，SEM，EDX检查烧结的PDC刀具 垂直车床测试和冲击测试，发现制造的PDC刀具的磨蚀比强烈依赖于烧结金刚石层的钴含量。不添加钴粉的PDC刀具表现出最佳的耐磨性，而通过添加4％质量的钴粉进行烧结的PDC刀具则显示出最差的磨蚀率，这直接证明了通过减少残余钴的含量可以证实。 PCD层将大大提高PDC刀具的耐磨性。提出了一种基于统计计算的无损表征方法，利用Matlab和Image-J软件定量研究了PCD层中钴含量以及残余钴平均粒径与耐磨性之间的关系，这就为揭示PDC刀具分析中与钴有关的耐磨性开辟了一条新的技术路线。此外，发现在PCD /硬质合金的界面中出现了富钴的狭窄区域，这被认为是引起PCD层从硬质合金上分层的主要原因。还有趣的是发现添加的钴粉百分比似乎对PDC刀具的冲击性能没有不利影响。