【摘要】 采用经过氧化改性后的木薯淀粉作为凝固剂进行氧化铝陶瓷原位凝固成型研究。研究了氧化淀粉添加量对陶瓷浆料流变特性以及成型素坯的密度、干坯强度的影响,测定了经1700℃烧结后瓷体的密度和强度。结果表明:当在固相体积分数为55%的氧化铝浆料中加入0.5%～1.5%(质量分数,下同)的氧化淀粉时,淀粉-氧化铝浆料的表观粘度随氧化淀粉添加量的增大而提高,但均小于0.4Pa·s。制备出的坯体致密、均匀,体积密度大于60%;干坯强度随淀粉添加量的增大而提高,均在7MPa以上,当氧化淀粉量为1.5%时,可达12MPa。烧结后氧化铝陶瓷的抗弯强度均在220MPa以上,其中当淀粉加入量为1.0%时,陶瓷的抗弯强度可达307MPa;烧结体的致密度随着淀粉加入量的增大而下降,当淀粉加入量小于1.0%时,烧结体的相对密度在96%以上,与注浆成型制备的烧结体的致密度相当。通过添加少量氧化淀粉,可实现氧化铝陶瓷的近净尺寸原位凝固成型,并可获得高致密度的陶瓷烧结体。更多还原

【Abstract】 The high-performance alumina ceramics were fabricated via the in-situ colloidal forming process with a small amount of oxidized starch by cassava as a consolidator/binder.The effect of the oxidized starch on the rheological behaviour of the ceramic slurries and the density and flexural strength of the green bodies and the sintered bodies were investigated.When the content of the oxidized starch ranged between 0.5wt%～1.5wt%,the alumina/starch slurries with a viscosity of <0.4 Pa·s were prepared,and then the high-density green bodies with complex shapes were produced.The flexural strength of all the green bodies was higher than 7 MPa.The green strength increased with increasing the content of the starch and a green strength >12 MPa could be obtained at the starch content of 1.5%.The flexural strength of the sintered bodies were higher than 220 MPa and reached the maximum value of 307 MPa at the starch content of 1.0%.Although the density of the sintered bodies decreased with increasing the starch content,the relative densities of the sintered samples were higher than 96% at the starch content of below 1.0%.It is concluded that the high-performance alumina ceramic with the homogeneous microstructure and high density can be formed via in-situ colloidal consolidation process with a small amount of the oxidized starch.更多还原