Formation and Sintering Characteristics of Aluminum Borate Whiskers

A boric acid‐stabilized aluminum acetate powder was decomposed to aluminum borate (Al18B4O33) by calcining at 1000°C. The powder was then ball‐milled, compacted, and fired to temperatures of 1500°, 1600°, and 1700°C for a period of 1 h. The resulting aluminum borate ceramic had a whiskerlike grain morphology, with the whisker length approaching 20 μm and a diameter of 2–3 μm. The sintered compact showed no shrinkage upon firing, had a porosity of ∼50%, a narrow pore size distribution, and an average pore size of 1–3 μm.