To improve the oxidation and graphitization resistances of the polycrystalline diamond (PCD), Ti coating was deposited on the diamond powders via magnetic sputtering method, which achieved a uniform TiC protection barrier in PCD during the sintering process. The phase compositions, microstructures and thermal stability of Ti-PCD were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and thermal gravimetric-differential scanning calorimetry (TG-DSC). The results demonstrate that the oxidation and graphitization resistances of PCD are strengthened due to the existence of TiC phase, which acts as an effective inhibitor. The as-received inhibitor delays the oxidation and graphitization of PCD, elevating their initial temperature by ∼50 °C and ∼100 °C, respectively. During the annealing treatment of Ti-PCD, the priory oxidation of TiC, which produces TiO₂ as an oxygen barrier, postpones the diamond oxide. Moreover, the TiC barrier also protects diamond grains from direct contact with cobalt, thus a lower cobalt-catalytic graphitization, and yields to an improved graphitization resistance of PCD. The enhanced oxidation and graphitization resistances of PCD are of significant importance for practical applications to elevated temperatures.

为了提高多晶金刚石（PCD）的抗氧化性和抗石墨化性，通过磁溅射方法在金刚石粉末上沉积了Ti涂层，从而在烧结过程中在PCD中获得了均匀的TiC保护层。通过X射线衍射（XRD），俄歇电子能谱（AES），扫描电子显微镜（SEM）和热重差示扫描量热法（TG-DSC）对Ti-PCD的相组成，微观结构和热稳定性进行了表征。结果表明，由于TiC相的存在，增强了PCD的抗氧化性和抗石墨化性，而TiC相是有效的抑制剂。如此收到的抑制剂延迟了PCD的氧化和石墨化作用，使它们的初始温度分别提高了约50°C和约100°C。₂作为氧气的阻挡层，会延迟金刚石的氧化。此外，TiC阻挡层还可以保护金刚石晶粒不直接与钴接触，从而降低钴催化的石墨化作用，并提高PCD的抗石墨化性。PCD增强的抗氧化性和抗石墨化性对高温实际应用具有重要意义。