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High‐Pressure Synthesis of Heat‐Resistant Diamond Composite Using a Diamond‐TiC 0.6 Powder Mixture
Author(s) -
Hong ShiMing,
Akaishi Minoru,
Yamaoka Shinobu
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb02109.x
Subject(s) - diamond , materials science , composite number , vickers hardness test , sintering , microstructure , composite material , carbon fibers , metallurgy
The sintering behavior of synthetic diamond with a grain size of 2‐4 µm was investigated at high pressure and high temperatures (6.5 GPa and 1600°‐1900°C, respectively) in the presence of TiC 0.6 or TiC. No well‐sintered diamond composite was synthesized from a diamond‐TiC powder mixture under the examined conditions; however, a well‐sintered diamond composite with a homogeneous microstructure was synthesized under the conditions of 6.5 GPa and temperatures >1800°C using a diamond‐TiC 0.6 powder mixture. The diamond composite was hard (Vickers hardness of 45 GPa) and was composed of diamond and TiC, in which TiC was formed via the reaction of TiC 0.6 and carbon atoms of diamond. Neither graphitization nor cracking was observed in or on the composite after successive heat treatment at 900°‐1400°C for 30 min each under vacuum. The Vickers hardness of the composite that was treated at 1500°C decreased to 40 GPa, whereas the Vickers hardness values for composites treated at temperatures of <1400°C were not changed. The present diamond composite is believed to be one of the most heat‐resistant materials among the superhard composites and can be used as heat‐resistant tools for superhard materials.