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

• Synthesize two insulating greases which can be used in electrical equipment.
• Nanometer SiO2 and TiO2 can greatly increase the grease volume resistivity.
• Nanometer TiO2 possess good tribological properties.
• Nanometer SiO2 possess good friction-reducing property.

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.