Abstract:

 Graphite/nanosized ZrO2 (GN ZrO2) composite powder was successfully prepared, with ZrOCl2·8H2O being predecessor, by surface modification on the natural flaky graphite particles using a heterogeneous nucleation technique. The effect of the amount of ZrO2 on hydrophilicity of the composite powders was investigated. Hydrophilicity of GN ZrO2 composite powders being modified was greatly improved. Composite powders were characterized by Zeta potential testing instrument and TGA-DSC analytical apparatus respectively. Isoelectric points of composite powder varied from pH=2.5 to pH=5.3 and the antioxidation property improved to some degree because the oxidation gravimetric ratio decreased from 98.9% to 93.1%. In addition, SEM photographs and the EDS analysis indicated that the graphite surface was coated with a layer of dense nano-sized ZrO2 particles, whose size was dozens of nanometers. XPS results showed that the surface of graphite powders exhibited Zr characteristic peak and the electron binding energy of C1s shifted by 0.4 eV toward the higher side.

Key words: heterogeneous nucleation; natural flaky graphite; zirconium oxide; hydrophilicity; oxidation resistance