复合添加制备Si₃N₄多孔陶瓷材料的研究

【作者】 崔霞；

【导师】 赵昆渝；

【作者基本信息】 昆明理工大学 ， 材料学， 2005， 硕士

【摘要】 本课题以硅粉为原料,以碳粉和尿素为造孔剂,以Al₂O₃、Y₂O₃、Fe、Al为烧结助剂,采用常压反应结合造孔剂法制备氮化硅基多孔陶瓷。本文通过实验系统研究了造孔剂、烧结助剂、成型压力等工艺因素对制备材料的XRD、孔特性（显气孔率、孔径、孔结构）及性能的影响,并探讨了其相互关系,有助于精确控制多孔陶瓷的孔特性与性能,从而制备出性能优良的氮化硅多孔陶瓷。 研究结果表明:采用反应烧结,结合常压烧结工艺可制备出Si₃N₄基多孔陶瓷材料;对添加单一烧结助剂（Al₂O₃与Y₂O₃）与复合添加（Al₂O₃、Y₂O₃、Fe、Al）的试样进行了物相分析,试样都有α-Si₃N₄和β-Si₃N₄生成,且复合添加的效果明显。 随着造孔剂含量的增加,试样的显气孔率增加,平均气孔孔径增大。添加造孔剂（碳粉与尿素）在25%内,可制得平均孔径在16μm-22μm之间的氮化硅多孔陶瓷,在复合添加Al₂O₃、Y₂O₃、Fe、Al、碳粉和尿素的条件下,添加碳粉试样的显气孔率变化幅度高于添加尿素的试样,平均孔径低于同含量添加尿素的平均孔径,气孔分布均匀。 在单一添加氧化物作为烧结助剂的条件下,氧化物含量在20%内,添加Y₂O₃与添加Al₂O₃试样的平均孔径均在14.87μm～16.53μm之间,添加Y₂O₃试样的气孔分布均匀。 对添加相同含量Al₂O₃、Y₂O₃、Fe粉、Al粉,不同含量的C粉、尿素的条件下,碳粉含量的增加可提高材料的显气孔率,降低材料的抗压强度;在气孔率相同的情况下,增加成型压力可提高制品的抗压强度。 此外,论文还对氮化硅多孔陶瓷的硬度、抗弯强度进行了初步探讨。更多还原

【Abstract】 The paper discussed that Silicon-nitride based porous ceramic was prepared by reaction-sintering and pressless-sintering with the powder of Si as raw material, Al2O3、Y2O3 Fe and Al as sintering aids, carbon and urea as pore-forming agent. In the paper, the effect of some important factors including pore-forming material, sintering aids, forming pressure on XRD and the pore properties (including apparent porosity, pore size, pore structure) of Silicon-nitride based porous ceramics were researched and analyzed systematically. Moreover, some effective methods in accurately controlling pore properties of porous ceramics were proposed. In order that pore properties of Silicon-nitride based porous ceramics are controlled accurately and excellent functions were obtained.The result showed that Silicon-nitride based porous ceramic was fabricated by the complex technology. The samples of Al2O3 and Y2O3 as sintering aids and the samples of Al2O3、 Y2O3 Fe and Al as sintering aids are composed of β- Si3N4 and a-Si3N4 . The effect of adding Al2O3、 Y2O3 Fe and Al as sintering aids were obvious.With the content of pore-forming agent increasing, apparent porosity and average pore size were increased. Si3N4 porous ceramics with average pore size from 16μm to 22μm were obtained by adding pore-forming agent (carbon and urea) in 25%. The pore of samples adding carbon distributed uniform, which apparent porosity changed sharper than apparent porosity adding urea and average pore size smaller than that adding urea.With the condition of only adding oxidization as sintering aids and the content of Al2O3、 Y2O3 in 20%, average pore size change from 14.87μm to 16.53μm. The pore of samples adding Y2O3 distributed uniform.With the condition of the content of Al2O3(2%)、 Y2O3(8%)、 Fe(1%)、 Al(1%), apparent porosity increased and pressing strength decreased with the content of carbon increasing. With the same of apparent porosity, increasing forming pressure can increase pressing strength.In addition, the hardness and flexural strength of Si3N4 porous ceramics were tentatively discussed.更多还原