Enhanced oxidation and graphitization resistance of polycrystalline diamond sintered with Ti-coated diamond powders. (15th April 2020)

• Record Type: Journal Article
• Authors: Sha, Xiaohua; Yue, Wen; Zhang, Haichao; Qin, Wenbo; She, Dingshun; Wang, Chengbiao
• Is Part Of: Journal of materials science & technology. Volume 43(2020)
• Page Start: 64
• Page End: 73
• Publication Date: 2020-04-15
• Subjects: Polycrystalline diamond -- Ti-coated diamond powder -- TiC barrier -- Oxidation resistance -- Graphitization resistance; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2020.01.031
• Languages: English
• ISSNs: 1005-0302

Abstract

Abstract: 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.