This paper studies the effect of a series of factors on the friction and wear behavior of steel with a brush plated layer of Pb, Sn or Pb-Sn-Cu under boundary lubrication. Factors studied include: load, sliding speed, thickness of plated layer and substrate hardness. The experimental set-up consists of a ball-on-disc machine. Based on the stress state of the ball and disc during rubbing, a mathematical expression of the friction coefficient is derived. The theoretical values were found to be in good agreement with the experimental values. Finally, the effect of various factors on the frictional coefficient is discussed in detail using this model.Presented at the 45th Annual Meeting In Denver, Colorado May 7–10, 1990