不同pH值下磷酸二氢铵(ADP)溶液成核过程研究

利用全程摄像的方法测定了不同情况下ADP过饱和溶液的诱导期,研究了不同pH值、不同温度的ADP过饱和溶液的成核过程,讨论了pH值、温度和过饱和度S等因素对诱导期的影响。结果表明:改变pH值后,在同一过饱和度下,溶液的稳定性在不同温度间差异较小,更利于晶体在较高的温度下稳定快速的生长;改变pH值后,溶液在整个过饱和度范围内更趋向于均匀成核。根据经典均匀成核理论,针对ADP溶液均匀成核的状况计算出了不同pH值和温度下的固-液界面张力、临界成核功等成核参数,并从上述参数的相互比较中得到了改变pH值后溶液稳定性变强的微观原因。最后通过对表面熵因子的计算,确定了ADP晶体的微观生长机制为连续生长模式。

Investigation on the Nucleation Induction Period of ADP's Solution with Different pH Values

For different pH values,the nucleation of NH4H2PO4 (ADP) supersaturation solution was investigated under different temperatures.The induction period with different growth conditions of ADP solution was measured by the method of photography,and the influence of some factors such as pH value,temperature and supersaturation to the induction period was discussed.The results indicate that:the difference of the stability of solution which has the same supersaturation between the different temperatures is unobviou...