关键词: 铁离子;磷酸氢二铵;介稳区宽度;晶体生长速率

Abstract: First of all,the crystallization metastable zone width of diammonium phosphate(DAP)solution with different contents of iron ions(Fe3+)was determined by dynamic laser method.Secondly,the effect of Fe3+ on the growth rate of DAP was studied by single crystal growth method with inverted microscope.In addition,the effect of Fe3+ on the regularity of DAP particles was investigated by analyzing the particle size distribution.The experimental results show that with the increasing of Fe3+ concentration from 0 to 0.007,metastable zone width increases to 7.68 ℃ from 3.32 ℃,the growth rate of the single crystal in all directions is reduced gradually.When the percentage of iron ion mass concentration X(Fe3+)=0.005,the crystal rate of x direction of diammonium phosphate(Gx)decreases from 60.29 nm·s-1(no adding Fe3+)to 28.35 nm·s-1 in the solution with the degree of supersaturation △C=6 g·(100 g)-1,and the average particle diameter D50 decreases from 267.1 μm(no adding Fe3+)to 137.6 μm and the crystal particle volume fraction of 40-80 mesh is reduced from 88.85％(not adding Fe3+)to 48.75％.The repeatability of the product particle size distribution declines.

Key words: Fe3+;diammonium phosphate;metastable zone width;crystal growth rate