Investigation of tribological properties of silicon nitride ceramic composites sliding against titanium alloy under artificial seawater lubricating condition

In order to study the possibility of silicon nitride based composites-metal as a material for seawater sliding pairs, the friction and wear properties of Si3N4-hBN composites sliding against titanium alloy in seawater and salt water were investigated, respectively. The experimental results indicate that a series of tribochemical reactions occurred on the wear surfaces, and the reaction products apt to aggregate into a tribochemical film with the assistance of ions in seawater. Because of the formation of a tribochemical film (composed of some oxides and hydroxides), the wear surfaces could be polished and friction pairs entered to the status of liquid lubrication when hBN content was 30%. From the tribological point of view, it seems that Si3N4-hBN composite is a very good mating material under seawater condition.