Tribological properties and insulation effect of nanometer TiO₂ and nanometer SiO₂ as additives in grease

Abstract New greases were synthesized using oleophilic nanometer-TiO₂ and nanometer-SiO₂ as additives. When the additives in naphthenic oil is 0.1 wt%, the alternating current (AC) breakdown strength is enhanced by 10.4% and 8.2% at power frequency, respectively. Also the grease volume resistivities are improved by 23% and 30% compared with base grease, which use naphthenic oil as base oil. The greases tribological behaviors were explored. Scanning electron microscope linked with energy dispersive X-ray spectroscope was utilized in order to analyze these scratches. The good tribological characteristics of nanometer-TiO₂ greases and the good friction-reducing characteristic of nanometer-SiO₂ greases are ascribed to the nanoparticles mechanical effect, and are also ascribed to the protect film generated by Ti and Si deposited or metallic oxide.