Abstract: Experiments on preparation of Fe₃O₄-coated mica (mica/Fe₃O₄) pearlescent pigment by co-precipitation method were performed to discuss influences of several crucial parameters on final products.It was also found that different coating effect including smoothness,compactness,and colour deepness were caused by different factors,such as  pH,amount-of-substance ratio of Fe³⁺ to Fe²⁺,and temperature.Samples were characterized by HRSEM,XRD，and Color i5 type color measurement device.Optimum preparation parameters of mica/Fe₃O₄ pearlescent pigment were obtained as follows:pH=9.2,concentration of sodium hydroxide was 0.5 mol/L,amount-of-substance ratio of Fe³⁺ to Fe²⁺  was 1.6,and reaction temperature was 75 ℃.

Key words: Fe₃O₄, co-precipitation, pearlescent pigment, mica