中文摘要：

Ceramic bond c BN composites with large pores were prepared by firing at 740 ℃ for 1 h using Na2O-Al2O3-B2O3-SiO2 glass and c BN abrasives（ particles size 0.150 mm /0.124 mm） as main starting materials,c BN micro-particles（ particles size 0. 014 mm） as the additive,and NH4HCO3 as the pore forming agent. The effect of NH4HCO3 and c BN micro-particles on the microstructure and properties of c BN composites was studied. The results show that for the c BN composite without c BN micro-particles the porosity obviously increases when the NH4HCO3 addition increases from 0 to 21 mass%,and increases slightly when the NH4HCO3 addition increases from 28 mass% to 42 mass%; and the bending strength decreases with the NH4HCO3 addition increasing. For the c BN composite with 14 mass% c BN microparticles,the porosity increases continuously with the NH4HCO3 addition increasing,achieving 56. 14% for the NH4HCO3 addition of 42 mass%,while,an obvious decrease of the bending strength is obtained. It is clearly indicated that the c BN micro-particles contribute to the high porosity and high strength of the porous ceramic bond c BN composites.

英文摘要：

Ceramic bond cBN composites with large pores were prepared by firing at 740 ℃ for 1 h using Na2O -Al2O3-B2O3 -SiO2 gluss and cBN abrasives （particles size 0. 150 mm/0. 124 mm） as main starting materials, eBN micro-particles （particles size O. 014 mm ） as the additive, and NH4HCO3 as the pore forming agent. The effect of NH4HCO3 and cBN micro-particles on the microstructure and properties of cBN composites was studied. The results show that for the cBN composite without cBN micro-particles the porosity obviously increases when the NH4HCO3 addition increases from 0 to 21 mass% , and increases slightly when the NH4HCO, addition increuses from 28 muss% to 42 muss% ; and the bending strength decreases with the NH4HCO3 addition increasing. For the cBN composite with 14 mass% cBN micro- particles, the porosity increases continuously with the NH4HCO3 addition increasing, achieving 56. 14% for the NH4HCO3 addition of 42 mass% , while, an obvious decrease of the bending strength is obtained. It is clearly indicated that the cBN micro-particles contribute to the high porosity and high strength of the porous ceram, ic bond cBN composites.