降温速率对磷酸二氢铵介稳区影响的研究

采用聚焦光束反射测量（FBRM）技术测定了磷酸二氢铵溶液介稳区宽度。测定了不同降温速率下磷酸二氢铵溶液的成核温度，得到对应的磷酸二氢铵结晶介稳区宽度。结果表明：在降温速率一定时，磷酸二氢铵溶液过冷度随温度降低而增加，介稳区变宽；在不同降温速率下，介稳区宽度随降温速率增加而增加，其中降温速率为1.0 ℃/min时介稳区宽度最大，降温速率为0.2 ℃/min和0.1 ℃/min时介稳区宽度不变。

Study on effects of cooling rate on ammonium dihydrogen phosphate′s metastable zone

The technology of focused beam reflectance measurement（FBRM） was used to test the crystallization metastablezone width of the ammonium dihydrogen phosphate solution.By determination of the nucleation temperature of ammonium di-hydrogen phosphate solution under different cooling rates，the ammonium dihydrogen phosphate′s metastable zone width data were obtained.Results showed that the supersaturated concentration and metastable zone width of ammonium dihydrogen phosphate solution increased along with the decrease of temperature under the same cooling rate.Under different cooling rates，ammonium dihydrogen phosphate metastable zone width increased with the increase of cooling rate，and the largest metastable zone width was generally at the cooling rate of 1.0 ℃/min.When the cooling rates were 0.2 ℃/min and 0.1 ℃/min， the width of metastable zone remained constant.