Mechanical properties of large-sized thin architectural ceramic plate enhanced by alumina fibres and in situ mullite whiskers

Abstract

The fibres reinforced thin architectural ceramic plates of 900?1800?2.5mm with excellent mechanical properties were prepared by fast-sintering method using a controllable fibre dispersion process. The effects of ball-milling time on dispersity, average length-to-diameter ratio and microstructure of alumina fibres were investigated. Meanwhile, the effects of alumina fibre contents on the bulk density, water absorption, phase transformation and microstructure of the thin ceramic plate were researched. It was found that the two-step ball-milling process can effectively control the average length-to-diameter ratio of alumina fibres, achieving a good dispersion mixture of fibres and ceramic powders. Ceramics bulk density and bending strength increase with fibre contents rise from 0 to 5 wt.% and then decrease with further fibre content addition from 5 to 15wt.%. The in situ formed mullite whiskers via fast-sintering method are beneficial for protecting fibres and fibre/matrix interfaces. The maximum value of bending strength and fracture toughness reach 147MPa for 5 wt.% fibre contents and 2.6MPa?m1/2 for 9 wt.%fibre contents, corresponding to the strengthening of alumina fibres and the formation of mullite whiskers in fibre/matrix interfaces and matrix via fast-sintering process.