Fabrication of novel BPO4 ceramic foams using the combination of the direct foaming method and freeze-drying techniques

In this study, ammonium phosphate monobasic and boric acid were used as the primary starting materials to produce BPO4 powder by solid-state reaction. Using BPO4 powders as the main raw material, BPO4 ceramic foams were prepared for the first time using the direct foaming method and freeze-drying techniques. The effects of the additive content and solid loading on the slurry's rheological behavior were investigated, and the microstructures and properties of the as-prepared BPO4 ceramic foams were examined. The results reveal that the porosity of the BPO4 ceramic foams synthesized at 1223 K ranged from 84.2% to 90.4%, the compressive strength ranged from .12 MPa to .72 MPa, and the thermal conductivity ranged from .32 W/(m center dot K) to .74 W/(m center dot K) (298 K). The findings of this study have great significance for the development of new thermal insulation ceramic materials.