Study On Light Color Conductive Powder Use Pyrophyllite As Substrate

In order to overcome traditional conductive powders’ defects such as dark color, high price and unstable conductive property, composite conductive powders use pyrophyllite as substrate were prepared. On one hand, it can reduce the cost of conductive powders, on the other hand it can expand the applying of pyrophyllite, and this kind of preparation provides a novel method to cheaply produce mineral-matrix functional materials.Composite conductive powders of pyrophyllite coated with antimony-doped tin oxide nanoparticles were prepared by chemical co-precipitation. Effects of hydrolysis temperature, pH value, content of SnCl4, content of doped antimony, calcination temperature and time on the resistivity of composite conductive powers were studied. The results showed that when SnCl4and doped antimony additions are100%and16%respectively, composite conductive powders with the resistivity of26Ω·cm could be prepared by hydrolyzing at60℃under pH value1.0, and finaly calcined at600℃for1h.XRD results showed that the SnO2has a tetragonal phase, antimony doping does not bring about a new object phase or change the crystal structure of SnO2. Sb has different state when calcinated at different temperature:when calcination temperature is low, Sb3+is the main state, and it will be oxygenated to Sb5+during the temperature increasing, if the calcination temperature is too high, the concentration of Sb3+will increase again. Such fact is the reason of composite powers have different resistivity at different calcination temperature.Composite conductive powders of pyrophyllite coated with fluorine-doped tin oxide were prepared by chemical precipitation method use pyrophyllite, SnCl4·5H2O and NH4HF2as raw materials. Effects of hydrolysis pH value, content of doped fluorine, calcination temperature and time on the resistivity of composite conductive powers were studied. The partical size of pyrophyllite also has great impact on the resistivity of products. Composite powders with the resistivity of4.6KΩ·cm could be prepared by the condition of pH=2, doped fluorine addition is40%and calcined at600℃for1h.