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By temperature gradient method under high pressure and high temperature(HPHT),with NiMnCo alloy as the solvent metal,at diamond-stable region of about 5.4 GPa and 1500 K,metastable regrown graphite crystals of different morphology were synthesized.With B as an additive incorporated into the NiMnCo-C system,metastable regrown graphite crystals of sphere-like shape were firstly obtained under HPHT.If the growth system does not contain B,sheet-like regrown graphite crystals,most with regular hexagonal morphology,are grown upwards and standing vertically in the metal solvent.When B additive of 1.0 wt pct was added into carbon source(graphite powder),all metastable regrown graphite crystals took on the habit of regular sphere-like morphology,and were grown by a spiral layer growth mechanism.
By temperature gradient method under high pressure and high temperature (HPHT), with NiMnCo alloy as the solvent metal, at diamond-stable region of about 5.4 GPa and 1500 K, metastable regrown graphite crystals of different h Incorporated into the NiMnCo-C system, metastable regrown graphite crystals of sphere-like shape were obtained under HPHT.If the growth system does not contain B, sheet-like regrown graphite crystals, most with regular hexagonal morphology, are grown upwards and standing vertically in the metal solvent. Wang B additive of 1.0 wt pct was added into carbon source (graphite powder), all metastable regrown graphite crystals took in the habit of regular sphere-like morphology, and were grown by a spiral layer growth mechanism.