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)
was studied. 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 than 1.2L·h-1. Under other conditions the precipitate was γ-AlOOH in the experimental range. The sequence of phase transformation of
γ-AlOOH during heating was found to be γ-AlOOH →γ-Al2O3→δ-Al2O3→θ-Al2O3→α-Al2O3; while that of NH4AlO(OH)HCO3 was found to be NH4AlO(OH)HCO3 →amorhous Al2O3→θ
-Al2O3→α-Al2O3. The transformation temperatures of NH4AlO(OH)HCO3 to θ-Al2O3 and α-Al2O3 were both about 100→ lower than those of γ-AlOOH. γ-AlOOH can transform to
α-Al2O3 completely by calcining at 1200℃ for 1h, and the obtained powder,with a particle size of 150nm, can be sintered to 84.46% relative density at 1450→
for 2h. NH4AlO(OH)HCO3 can transform to α-Al2O3 completely by calcining at 1100℃ for 1h, and the obtained powder, with a particle
size of 70nm, can be sintered to 97.80% relative density under the same sintering condition.
参考文献
| [1] | 李世普. 特种陶瓷工艺学, 武汉: 武汉工业大学出版社, 1990. 20--21 2 朱宣惠, 许迪春. 硅酸盐学报. 1992, 20 (1): 48--54 3 Iler R K. Fibrillar Colloidal Boehmite: J. Am. Ceram. Soc., 1961, 44 (12): 618--24 4 Wilson S J. Mineral Mag., 1979, (43): 301--308 5 Dynys FW, Halloran J W. J. Am. Ceram. Soc., 1984, 67 (9): 598--601 |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%