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.
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.
基金
supported by the National Natural Science Foundation of China(Grant No.51272205,51302208)
Doctoral Fund of Ministry of Education of China(Grant No.20130201120003)
