The lubrication of both aluminium–silicon and model silicon surfaces with calcium sulphonate and an organic antiwear additive

•Calcium carbonate based tribofilms are generated on silicon surfaces.•The combination of detergent+organic antiwear additive reduces wear more so than detergent alone.•Tribofilm topography has altered significantly when compared against those films generated from calcium sulphonate.

The lubrication of a line contact between an aluminium–silicon cylinder liner and a chromium steel piston ring, which operates under mild wear boundary lubricated conditions, has been investigated. The lubricant was synthetic six centistokes poly alpha olefin based, into which calcium sulphonate and an organic antiwear additive were blended. Calcium carbonate based tribofilms were generated exclusively on silicon grains within the aluminium alloy. Replication of the contact conditions using chromium steel pin on silicon plate generated larger scale tribofilms, which comprised small, interlinked pads; these were chemically identical to those on the aluminium–silicon alloy. The thickness and elastic modulus of the tribofilm generated on the silicon substrate were determined and the results compared against previous findings by the current author.

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