A novel approach to fabricate mullite ceramic foams with high porosity and mechanical strength using fly ash hollow spheres (FAHSs) as the only raw material was reported for the first time, in which FAHSs served as both matrix and pore-forming agent. It was demonstrated that uniform FAHS ceramic foams without cracks could be fabricated by both direct stack sintering method and gel-casting route. The effect of sintering temperature on linear shrinkage, porosity, phase composition and mechanical properties was investigated. With the increase of sintering temperature from 1200 °C to 1350 °C, the fracture mechanism changed from fracturing along FAHSs to fracturing across FAHSs, and the compressive strength of the FAHS ceramic foams increased from 4.4 MPa to 33.4 MPa. The FAHS ceramic foams exhibited high porosity in the range of 73–81% and high mechanical strength, which benefited from the dense assembling of small FAHSs with natural diameter distribution and excellent wall-thickness uniformity.

首次报道了使用粉煤灰空心球（FAHS）作为唯一原料制备具有高孔隙率和机械强度的莫来石陶瓷泡沫的新方法，其中FAHS既用作基质又用作造孔剂。结果表明，直接叠层烧结法和凝胶浇铸法均可制备出无裂纹的均匀FAHS陶瓷泡沫。研究了烧结温度对线性收缩率，孔隙率，相组成和力学性能的影响。随着烧结温度从1200°C升高到1350°C，断裂机理从沿FAHS的断裂转变为沿FAHS的断裂，FAHS陶瓷泡沫的抗压强度从4.4 MPa增加到33.4 MPa。