• The Korean Journal of Ceramics
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• v.1 no.3
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• pp.125-130
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• 1995

Electrical discharge machinable $SiC-TiB_2$ composites were fabricated by hot-pressing. Their mechanical and electrical properties were determined as a function of $TiB_2$ content. The addition of $TiB_2$ to SiC matrix increased the strength and toughness and decreased electrical resistivity. The flexural strength and fracture toughness of SiC-40 vol% $TiB_2$ composited were approximately 50% higher than those of monolithic SiC ceramics. Microstructural analysis showed that the toughening was mainly due to the crack deflection, with some possible contribution from crack branching or microcracking.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.101-105
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• 1995

Electrical discharge machinable $Si_3N_4$ was fabricated with the addtion of 20-60 vol% TiN by gas pressure sintering. Their sinterability, microstructure, mechanical and electrical properties were characterized as a function of the TiN content. The addition of TiN up to 20 vol% increased the flexural strength and fracture toughness as compared with those of the monolithic Si3N4. For the TiN content higher than 40 vol%, the electrical resistivity was lower than $1062\Omega$.cm. The $Si_3N_4$ with the addition of 40 vol% of TiN appears to have the optimum considerable sinterability, mechanical and electrical properties, and machinability. A microstructural analysis showed that the enhanced toughening was due to the crack deflection.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.111-116
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• 1998

Silicon nitride is hard and tough ceramic material. Hereby, mechanical machinability is very poor. It has also high electrical resistance. Silicon nitride of extremely high electrical resistivity becomes conductive ceramic composite by adding 30 wt% TiN. Ceramics with high electrical conductivity can be electrical discharge machined. Using by the Electrical Discharge Machining (EDM) technique. $Si_3N_4-TiN$ ceramic composite with high electrical conductivity is utilized to make metal working tool. These tool materials have severe wear problem as well as oxidation. Post HIP processing after sintering $Si_3N_4-TiN$ ceramic composites was performed. The tribological property of $Si_3N_4-TiN$ composite as a function of content of TiN was investigated in air, at room temperature. The hardness, fracture toughness, and flexural strength were compared with the wear volume. SEM observation of wear tracks can make an explanation of wear mode of $Si_3N_4-TiN$ composite.