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 Ti C protection bar...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 Ti C 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 Ti C 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 Ti C, which produces Ti O2 as an oxygen barrier, postpones the diamond oxide. Moreover, the Ti C 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.展开更多
In this research,the advantages and disadvantages of the cylindrical grinding process of Polycrystalline Diamond Compacts(short for PDC) with vitrified and resin bond diamond grinding wheel are compared.The research r...In this research,the advantages and disadvantages of the cylindrical grinding process of Polycrystalline Diamond Compacts(short for PDC) with vitrified and resin bond diamond grinding wheel are compared.The research results show that the vitrified bond diamond grinding wheels,which use Ti-coated diamond grains as abrasive and glass ceramic as bond,have many advantages in grinding PDC.Compared with resin diamond grinding wheel,vitrified bond wheels lead to 35% grinding cost reduced,40% grinding time of each PDC saved,and the size precision of PDC improved(from ±0.03mm to ±0.01mm).When grinding feed is <0.10 mm,the grinding ratio increases with increased grinding feed.However,when the grinding feed exceeds 0.10 mm,the grinding radio decreases rapidly with the increasing of grinding feed.The disadvantage of this kind of grinding wheel is that the brightness of the ground PDC cylinder is not as shining as that processed by resin bond diamond grinding wheel.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51875537,41572359 and 51375466)the Beijing Natural Science Foundation(No.3172026)+2 种基金the Beijing Nova program(No.Z171100001117059)the Fundamental Research Funds for the Central University(No.2652018094)the Natural Science Foundation of Ningxia Province(No.2018AAC03200)。
文摘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 Ti C 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 Ti C 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 Ti C, which produces Ti O2 as an oxygen barrier, postpones the diamond oxide. Moreover, the Ti C 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.
文摘In this research,the advantages and disadvantages of the cylindrical grinding process of Polycrystalline Diamond Compacts(short for PDC) with vitrified and resin bond diamond grinding wheel are compared.The research results show that the vitrified bond diamond grinding wheels,which use Ti-coated diamond grains as abrasive and glass ceramic as bond,have many advantages in grinding PDC.Compared with resin diamond grinding wheel,vitrified bond wheels lead to 35% grinding cost reduced,40% grinding time of each PDC saved,and the size precision of PDC improved(from ±0.03mm to ±0.01mm).When grinding feed is <0.10 mm,the grinding ratio increases with increased grinding feed.However,when the grinding feed exceeds 0.10 mm,the grinding radio decreases rapidly with the increasing of grinding feed.The disadvantage of this kind of grinding wheel is that the brightness of the ground PDC cylinder is not as shining as that processed by resin bond diamond grinding wheel.
