稻壳低温制备多孔氮化硅陶瓷

Preparation of Porous Silicon Nitride Ceramic Using Rice Husk at Low Temperatures

以稻壳为原料,碳热还原法常压条件下合成出Si3N4粉体,进而模压成型,在低温下成功烧成了多孔氮化硅陶瓷。采用Archimedes法、三点弯曲法测量了烧结试样的密度、气孔率及抗弯强度。通过XRD测定了烧结试样的物相组成,并用SEM观察其显微形貌。结果表明：在1450℃到1550℃内均能烧成多孔氮化硅陶瓷,随着温度的升高,试样的气孔率逐渐降低,抗弯强度逐渐增强。1450~1500℃烧成试样的显气孔率为55.51%~35.15%,其抗弯强度为23.74~86.85 MPa,主要物相为β-Si3N4。

By using rice husks as raw materials, Si3N4 powder was prepared by the carbon thermal reduction under atmospheric pressure. Then porous silicon nitride ceramic was successfully fabricated by using made Si3 N4 powder after press molding at low temperature. Bulk density, apparent porosity and flexural strength of porous silicon nitride ceramics were tested by Archimedes-method, three-point bending measurement. The phase composition was analyzed by XRD, the microstructure of the fracture surface was observed by SEM respectively. The results showed that porous silicon nitride ceramic was successfully fabricated in the sintering temperature from 1400 to 1550 ℃. With the increase of temperature, the porosity decreased, but the flexural strength increased. When the sintering temperature is 1450-1500 %, porous Si3N4 ceramics were mainly composed of β-SiBN4 phase, the porosity of 55.51%-35.15% and the flexural strength of 23.74-86.85 MPa.