Friction and Wear Characteristics of Sintered Aluminum-Silicon in Ethanol-n-Hexane Mixtures

Abstract

Sintered aluminum-silicon (Al-Si) disks were slid against silicon nitride (Si₃N₄) pins in n-hexane, in ethanol and in ethanol-n-hexane mixtures to evaluate the influence of the ethanol content in ethanol-gasoline fuels on the friction and wear behavior. Friction and wear of sintered aluminum-silicon in n-hexane were higher than those in lubricants containing ethanol. Worn surfaces indicated that oxidative wear, abrasive wear, adhesive wear and brittle fracture of silicon particles took place on the sliding surface of the sintered Al-Si disk in n-hexane. Precipitation of oxidized aluminum and oxidized silicon on the sliding surface, abrasive wear, plastic deformation and adhesive wear were inhibited by the presence of ethanol. Friction and wear of sintered Al-Si disks in lubricant with high ethanol content were lower than those in lubricant with low ethanol content. Wear of Si₃N₄ pin in n-hexane was too small to be measured. Tribochemical wear of Si₃N₄ pins took place in lubricants containing ethanol.