Mullite/ZrO_2涂覆铝硅纤维布的界面设计与结构分析

Interface Design and Structure Analysis of Al-Si Fiber Fabrics Coated with Mullite/ZrO_2

针对航空航天热防护、高温窑炉保温、热风输送装置等领域隔热高温垫片的需求,以独居石型LaPO4（Monazite-（La））作为界面相,在铝硅纤维二维编织体表面涂覆氧化物的涂层,制备具有耐高温、低导热效果的高温隔热垫片材料。实验表明,独居石型LaPO4高温稳定,与氧化物纤维形成弱结合,可有效阻止裂纹从基体向纤维的扩展,可使纤维呈现明显的“拔出效应”。分别研究了硅溶胶、磷酸二氢铝溶液、磷酸镧溶液作为中间层对材料性能的影响,对涂层的相组成和涂层与基体间的界面显微结构进行了初步评价。制备的耐温材料可以在10001100℃长期使用,较通常无弱界面相的材料耐温性提高50100℃。

High temperature resistance, low heat conduction material prepared using Monazite-(La) LaPO_4 as the interphase and oxide coating coated on alumina fiber fabric is greatly needed in aerospace thermal protection, high temperature furnace thermal insulation, hot wind delivery mechanism and some other fields. Tests show that LaPO_4 is stable at high temperature and because it is weakly bonded with oxide fiber. It can effectively prevent cracks from growing from matrix into fiber and make the fiber present obvious 'pull out effect'. The influence of silica sol, Al(H_2PO_4)_3 solution and LaPO_4 solution as interface on material properties were studied. Preliminary evaluations of phase composition of the coating and the interface microstructure between the matrix and the coating have been conducted. Prepared heat insulation material can be long-time used at 1000~1100 oC, which is 50~100 oC higher than materials without weak interface.