摘要
研究了以硫酸铝铵和碳酸氢铵为原料合成碳酸铝铵的工艺条件．在实验条件范围内，将硫酸铝铵溶液以低于1．2L．h－1的速度加入到碳酸氢铵溶液中，可合成碳酸铝铵；在其它操作条件下，获得的产物为γ－AlOOHγ－AlOOH升温过程中的物相变化次序为：γ－AlOOH→γ－Al2O3→δ－Al2O3→θ－Al2O3→α－Al2O3;而碳酸铝铵的相变次序为：碳酸铝铵→无定型Al2O3→θ－Al2O3→α－Al2O3碳酸铝铵转变为θ－Al2O3和α－Al2O3的温度均比γ－AlOOH低约100℃γ－AlOOH在1200℃煅烧1h方可完全转变为α－Al2O3，其颗粒尺寸为150um；粉体经1450℃、2h烧结相对密度为84.46％；而碳酸铝铵在1100℃煅烧1h就可完全转变为α-Al2O3，其颗粒尺寸为70um，粉体在相同的烧结条件下相对密度可达97.80％
By using ammonium aluminium sulfate and ammonium hydro-carbonate as the starting materials, the synthesis of ammonium aluminium carbonate hydroxide (NH4AlO(OH)HCO3) wasstudied. It was found that NH4AlO(OH)HCO3 can be synthesized by adding ammonium aluminium sulfate solution to ammonium hydro--carbonate solution with a adding rate less than1.2L'h--1. Under other conditions the precipitate was γ-AIOOH in the experimental range. Thesequence of phase transformation of γ-AIOOH during heating was found to be γ--AIOOH → γAl2O3 → δ -Al2O3 → θ-Al2O3 →α-Al2O3, while that of NH4AlO(OH)HCO3 was found to beNH4AlO(OH)HCO3 →amorhous A12O3 → θ→Al2O3 →αA12O3. The transformation temperatures of NH4AlO(OH)HCO3 to θ-A12O3 and α-A12O3 were both about 100℃ lower than thoseofγ-AIOOH. γ-AIOOH can transform to α--A12O3 completely by calcining at 1200℃ for 1h, andthe obtained powder, with a particle size of 150um, can be sintered to 84.46% relative density at1450℃ for 2h. NH4AlO(OH)HCO3 can transform to α-A12O3 completely by calcining at 1100℃for 1h, and the obtained powder, with a particle size of 70um, can be sintered to 97.80% relativedensity under the same sintering condition.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第6期803-807,共5页
Journal of Inorganic Materials
基金
国家自然科学基金!59502007
国家教委优秀年轻教师基金
关键词
碳酸铝铵
烧结
热分解
氧化铝
超细粉末
NH_4AlO(OH)HCO_3, α-A1_2O_3, ultrafine powder, synthesis, sintering
