ABSTRACT

Two steps were involved in the preparation of the porous mullite ceramics: preparation of porous green body by foaming method combined with gelcasting, using alumina, silica and AlF₃ as raw materials and synthesis of needle-like mullite whiskers by vapor-phase reaction. Owing to the special pore structure of foaming method, the needle-like mullite crystals had enough space to develop with good structure. Most of the needle-like mullite crystals have diameters around 1.5 μm and lengths of >80 μm. By adjusting the amount of foaming agent, the open porosity varied from 66.3 to 85.5%, and the compressive strength and flexural strength decreased evidently, from 23.4 ± 1.8 to 4.9 ± 0.4 MPa and 9.7 ± 0.9 to 1.0 ± 0.1 MPa.

摘要

多孔莫来石陶瓷的制备包括两个步骤：以氧化铝、二氧化硅和AlF ₃为原料，通过发泡法结合凝胶注模法制备多孔坯体和通过气相反应合成针状莫来石晶须。由于发泡法的特殊孔结构，针状莫来石晶体有足够的空间发展，结构良好。大多数针状莫来石晶体的直径约为 1.5 μm，长度大于 80 μm。通过调节发泡剂用量，开孔率由66.3%变为85.5%，抗压强度和抗折强度明显下降，分别由23.4±1.8～4.9±0.4MPa和9.7±0.9～1.0±0.1MPa。