摘要:
采用无压烧结技术,以Si3 N4、AlN和Al2 O3为基体原料,淀粉为造孔剂,外掺5%(质量分数)Y2 O3作为烧结助剂,研究淀粉掺量对β-SiAlON(z=2)多孔陶瓷物相组成、微观结构和力学性能的影响规律.研究结果表明,当造孔剂掺量≤60%(质量分数)时,所制备多孔陶瓷的主相均为β-SiAlON,且当淀粉掺量在20%~40%(质量分数)时,气孔内壁形成柱状15R,而当淀粉掺量增加到60%(质量分数)时,气孔内壁则为致密的交错生长的层状12H;β-SiAlON多孔陶瓷的气孔形貌为椭球形,当淀粉掺量为20%(质量分数)时,以独立气孔为主,长轴约为30~80μm,而当淀粉掺量为60%(质量分数)时,以连通型气孔为主;当气孔率约为40%(淀粉掺量60%(质量分数))时,β-SiAlON多孔陶瓷的抗弯强度为117.3 MPa,是气孔大小相近氮化硅多孔陶瓷抗弯强度的1.5倍.高强度的基体、椭球形的气孔以及致密的交错生长的15R 或12H 孔壁是使β-SiAlON 多孔陶瓷具有高强度的主要原因.%β-SiAlON(z=2)porous ceramics were prepared by pressureless sintering with Si3 N4 ,AlN and Al2 O3 as matrix material,5wt% Y2 O3 as sintering additives.The influence rule of starch content on phase composi-tion,microstructure and mechanical properties were analyzed.The results show that the main phase of porous ceramics (starch content ≤60wt%)wereβ-SiAlON,the interface of pore were columnar crystal 15R with starch content 20%-40wt%,and lamellar 12H with 60wt%;Porous ceramics were ellipsoidal shape pore mor-phology,porous ceramic (starch content was 20wt%)was mainly in independent pore,major axises were 30-80μm,porous ceramic (starch content was 60wt%)was mainly in connected pore;the flexure strength ofβ-SiAlON porous ceramics was 117.3 MPa with the porosity 40% (starch content was 60wt%),which was 1.5 fold of Si3 N4 porous ceramics with similar size pores.High strength of matrix,ellipsoidal shape of pore and den-sity of pore interface with 12H or 15R were the primary cause of preparing high strengthβ-SiAlON porous ce-ramic.