MAGNETIC PIGMENTS AND PROCESS OF ENHANCING MAGNETIC PROPERTIES

摘要

A pearlescent pigment and a process for enhancing the magnetic properties of a pearl escent pigment. The pearlescent pigment has a layer with regions of ?-Fe2O3 and regions of a-Fe2O3. The magnetic properties of a pearlescent pigment may be enhanced by the steps of: providing a platelet pigment with a layer Of Fe2O3, with a magnetic susceptibility less than 0.1 x 10-5 m3/kg; reducing some or all of the Fe2O3 to Fe3O4; and oxidizing some or all of the Fe3O4 to ?-Fe2O3. The color difference (?E*) between the provided pigment and the resultant pigment is not more than about 5.