Wear Characteristics of Modified Plasma-Deposited Aluminum Bronze

Plasma-deposited aluminum bronze coatings (Cu-10 Al) have been shown to be superior to wrought aluminum bronze (AMS 4640) when mated against steel with a hydraulic oil lubricant. In this study a series of compositional changes of the plasma-deposited aluminum bronze resulted in another order-of-magnitude reduction in wear rate. This was achieved without an increase in the hardness of the material so the embeddability and conformability of the materials were not degraded. The coefficients of friction of the plasma-deposited materials were much lower than their wrought counterpart, but there was little further change in the coefficients as a function of compositional changes in the plasma-deposited materials.

The coating parameters and compositional studies were based on unidirectional wear tests with the Dow Corning Alpha Wear Test Machine LFW-1 using hydraulic fluid Mil H5606A at loads from 30 to 450 lb at constant speed. The wear scars and debris were examined using scanning electron microscopy and microprobe analyses, and these observations correlated with the microstructures of the deposits. Differences between the various plasma deposits were correlated with microstructural and compositional variations.