摘要
为了提高Al2O3-MgO-ZrO2层状复合陶瓷烧嘴材料的强度、韧性和热震性能,制备了SiC/SiO2-Al2O3-MgO-ZrO2新型陶瓷材料。结果表明,SiC/SiO2复合纳米粉体的添加大大增加了材料的体积密度,增强了材料的抗弯强度和断裂韧性。特别是经1850℃焙烧的样品,当SiC/SiO2复合纳米粉体的含量为7%(质量分数)时,试样的抗弯强度和断裂韧性分别提高了23.1%和25.5%,在热震温差超过1000℃的恶劣条件下,其残余抗弯强度保持率仍高达69%。SEM观察表明,单纯的Al2O3-MgO-ZrO2材料的断面有游离的柱状颗粒存在,而添加SiC/SiO2的样品,不同氧化物和非氧化物颗粒紧密结合,形成光滑圆润的波浪状结构,这一显微结构对提高材料的力学性能有重要作用。
SiC/SiO2 mixed nano powders were added into the Al2O3-MgO-ZrO2 system to improve the bending strength,fracture toughness and thermal shock performance of materials.The results show that the volume density obviously increased and the apparent porosity decreased after the addition of SiC/SiO2 mixed nano powders.The bending strength and fracture toughness were improved by 23.1 % and 25.5%,respectively,for the sample with the SiC/ SiO2 content of 7wt%.The retention of residual strength of SiC/SiO2-Al2O3-MgO-ZrO2 sample with the SiC/SiO2 content of 7wt% calcinated at 1850 ℃ is as high as 69% after a thermal shock treatment with the critical thermal shock temperature of 1000 ℃.The observation by SEM indicates that there are many free columnar particles in the fracture surface which may reduce the mechanical property of Al2O3-MgO-ZrO2 materials.On the other hand,the particles in the samples with SiC/SiO2 as an additive tightly connected,resulting in a kind of wave interface structure,which may play an important role in the improvement of the mechanical property of the multilayered ceramic nozzle materials.
