An Experimental Study of the Wear Caused by Loose Abrasive Particles in Oil

Abrasive powders were added to a highly-refined petroleum oil and run in a vane pump. With no antiwear additive, wear was successive and volumetric efficiency dropped rapidly. With 0.1% oleic acid or stearyl amine added to the oil the abrasive wear of the particles was essentially eliminated. Also, precoating the particles with the antiwear additive before adding to the base oil greatly retarded wear. Oleic acid performed best on iron oxide (basic), stearyl amine best on silica (acidic). No reduction in abrasive wear by oleic acid was observed when a steel ball was loaded against a grinding wheel. It is concluded that the antiwear additives prevent three-body abrasion (abrasion by loose Articles) by preventing the particles from adhering to one of the wing surfaces where they can act like small cutting tools.