| a | Department of Materials Science and Engineering, KAIST, 373-1 Kusung-Dong, Yusung-Gu, Daejeon 305-701, Republic of Korea |
| b | Institute of Industrial Technology, ILJIN Diamond Co., Ltd., 614-2 Oryu-Ri, Daeso-Myun, Eumsung-Kun, Chungcheongbuk-Do, Republic of Korea |
| c | Korea Atomic Energy Research Institute, 150 Deokjin-Dong, Yuseong-Gu, Daejeon 305-353, Republic of Korea |
Received 16 March 2011; revised 19 July 2011; Accepted 21 July 2011. Available online 28 July 2011.
Abstract
For the purpose of increasing microstructural homogeneity and enhancing the reinforcement-matrix interfacial area, cubic Boron Nitride, cBN particles were coated by nanocrystalline TiN by a sol–gel route that required neither the need for pH adjustment nor the use of surfactants or additives. Uniform shells of amorphous titania having thicknesses in the nanometers scale were formed on the surface of the cBN particles by hydrolysis and condensation reactions of titanium (IV) isopropoxide. The amorphous coated cBN powder was nitrided to crystalline TiN coated cBN by treating in NH3 gas at 900 °C. After nitridation the amorphous layer was completely converted to nanocrystalline TiN particles that uniformly covered the surface of cBN. Changes in the TiOx coated layer thickness and the size of the TiN particles were investigated as a function of alkoxide content. TiO2 nanoparticles were synthesized using the same reaction conditions, but without the presence of cBN. These nanoparticles were calcined in air at different temperatures (250–700 °C) and then nitrided at 900 °C. The nitridation behavior of TiO2 nanoparticles was studied as a function of calcination temperature.
