Porous mullite ceramics with different crystal shapes of mullite are fabricated by in-situ reaction with middle-grade kyanite as raw material, Al(OH)₃, γ-Al₂O₃, ρ-Al₂O₃ and α-Al₂O₃ as alumina sources. Effects of Al₂O₃ crystal types on morphology evolution and formation mechanisms of mullite, and properties of porous ceramics are investigated. Results show that mullite in the sample with Al(OH)₃ mainly shows acicular morphology, because its (001) plane has the minimum interplanar crystal spacing and maximal attachment energy, it grows fast along [001] direction by screw dislocation mechanism. With a successive slowdown in reactivities of Al(OH)₃, γ-Al₂O₃, ρ-Al₂O₃ and α-Al₂O₃, the amount and aspect ratio of mullite reduce, its growth mechanism gradually transforms into two-dimensional nucleation. Acicular mullite not only reinforces samples, but makes effective pore sizes smaller, which enable the sample with Al(OH)₃ to present low bulk density, high apparent porosity and linear changes, small average pore size and good mechanical strength.

与富铝红柱石的不同晶体形状的多孔莫来石陶瓷通过原位反应与中等等级蓝晶石为原料制造的，的Al（OH）₃，γ-Al系₂ ö ₃，ρ-Al系₂ ö ₃和α-Al系₂ ö ₃作为氧化铝源。研究了Al ₂ O ₃晶体类型对莫来石形态演变和形成机理以及多孔陶瓷性能的影响。结果表明，样品中的莫来石中含有Al（OH）₃主要表现出针状形态，因为其（001）面具有最小的晶面晶格间距和最大的附着能，因此通过螺旋位错机制沿[001]方向快速生长。与以Al（OH）的反应性连续减速₃，γ-Al系₂ ö ₃，ρ-Al系₂ ö ₃和α-Al系₂ ö ₃，莫来石的量和纵横比降低，其生长机制逐渐转变成两个维成核。针状莫来石不仅可以增强样品强度，而且可以减小有效孔径，从而使样品具有Al（OH）₃ 具有较低的堆积密度，较高的表观孔隙率和线性变化，较小的平均孔径和良好的机械强度。