Large single crystal diamonds were synthesized using Ti/TiC and Cu as additives in the Fe₆₄Ni₃₆-C system under 5.6 GPa and at 1543 K. The synthesized crystals were characterized by optical microscopy and infrared spectroscopy. Results show that both Ti and TiC react with N to form TiN and Ti (C_1-x, N_x), respectively, which leads to a poor nitrogen removal efficiency and a large number of inclusions and pits in the crystals. Co-doping TiorTiC with Cu promotes the decomposition of TiC to release Ti, which improves the nitrogen removal efficiency, and thereby reduces the number of defects and inclusions in the diamond crystals. A high-quality type IIa diamond crystal was optimally synthesized when the Ti/Cu contents were 1.70 wt.%/1.06 wt.% (Ti: Cu = 4: 2.5).

在Fe ₆₄ Ni ₃₆ -C体系中，在5.6 GPa和1543 K下，使用Ti / TiC和Cu作为添加剂合成了大型单晶金刚石。通过光学显微镜和红外光谱对合成的晶体进行表征。结果表明Ti和TiC均与N反应形成TiN和Ti（C _1-x，N _x）分别导致脱氮效率低和晶体中大量的夹杂物和凹坑。TiorTiC与Cu共掺杂可促进TiC分解以释放Ti，从而提高脱氮效率，从而减少金刚石晶体中的缺陷和夹杂物数量。当Ti / Cu含量为1.70 wt％/ 1.06 wt。％（Ti：Cu = 4：2.5）时，可以最佳地合成高质量的IIa型金刚石晶体。