利用尿素分解的均相沉淀法制得了球形 Al(OH)_3颗粒。影响颗粒形成、尺寸及其分布的主要因素为加热温度和沉淀时间等。球形 Al(OH)_3颗粒中含有[SO_4~(2-)],需在850℃以上开始分解。分解时,首先形成γ-Al_2O_3,比表面积增加,并在1000℃左右达最大值。此后α-Al_2O_3开始形成,比表面积下降。不同温度分解后的粉料烧结试验表明,α-Al_2O_3比γ-Al_2O_3具有更好的烧结性。另外,Al(OH)_3颗粒越小,分解后的Al_2O_3颗粒也越小,其烧结性能越好。 The spherical Al (OH) 3 particles were prepared by homogeneous decomposition of urea. The main factors affecting the formation, size and distribution of particles are heating temperature and precipitation time. Spherical Al (OH) _3 particles contain [SO_4 ~ (2-)], to be started at 850 ℃ decomposition. Decomposition, the first formation of γ-Al 2 O 3, the specific surface area increased, and reached a maximum at about 1000 ℃. After α-Al 2 O 3 began to form, the specific surface area decreased. The sintering tests of powders after different temperature decomposition show that α-Al_2O_3 has better sinterability than γ-Al_2O_3. In addition, the smaller the Al (OH) 3 particles, the smaller the particles of Al 2 O 3 decomposed, and the better the sintering performance.