Tribological Properties of Fe-Si-Cr-Al Quaternary System Fe₃Si under Water Lubrication

Tribological properties of Fe-Si-Cr-Al alloys (Fe₆₅Si₂₅Cr₅Al₅, Fe₇₀Si₂₀Cr₅Al₅, Fe₇₅Si₁₅Cr₅Al₅ and Fe₈₀Si₁₀Cr₅Al₅) in sliding against a Si₃N₄ ball under water lubrication were evaluated by using an Optimal SRV tribo-meter. The results indicate that the wear rates of Fe₆₅Si₂₅Cr₅Al₅ and Fe₇₀Si₂₀Cr₅Al₅ were lower than those of Fe₃Si and AISI 304 stainless steel. The wear rate of Si₃N₄ sliding against Fe₆₅Si₂₅Cr₅Al₅ and Fe₇₀Si₂₀Cr₅Al₅ were low. The wear rate of Fe₇₅Si₁₅Cr₅Al₅ and Fe₈₀Si₁₀Cr₅Al₅, on the other hand, were relatively higher than those of Fe₃Si and AISI 304 stainless steel. The chemical activity of Cr in Fe₇₀Si₂₀Cr₅Al₅ was higher than that of Al in Fe₇₀Si₂₀Cr₅Al₅. The enrichment of Cr₂O₃ on the worn surface of Fe₇₀Si₂₀Cr₅Al₅ hindered the tribochemical reaction between Si₃N₄ and water, which in turn accounted for the good tribological properties of Fe₇₀Si₂₀Cr₅Al₅. Compared with Fe₃Si, the wear rates of Fe₇₀Si₂₀Cr₅Al₅ at the loads of 30 N, 50 N, 70 N and 90 N decreased by 15.5%, 20.2%, 31.8% and 38.2%, respectively. Meanwhile, the wear rates of Si₃N₄ against Fe₇₀Si₂₀Cr₅Al₅ at the loads of 30 N, 50 N, 70 N and 90 N decreased by 67.9%, 36.9%, 46.6% and 50.6% respectively compared with those of Si₃N₄ against Fe₃Si.