Effects of Test Parameters on the Frictional Properties of Al/Diamond-Like Carbon Core-Shell Nanostructure-Textured Surfaces

A friction test is a beneficial means to analyze the tribological characteristics and advantages of materials and textured surfaces. However, the selected parameters of the friction test can significantly influence the outcome. In this study, several applied normal loads (10 mu N, 100 mu N, and 500 mu N) and counterface indenter tip radii (1 mu m, 5 mu m, and 100 mu m) were selected for testing of an Al/diamond-like carbon (DLC) core-shell nanostructure textured surface (CSNTS) and compared to a smooth DLC film deposited outside the textured area of the same surface. The effects of these friction test parameters were examined, along with the mechanisms that control these effects. It was found that the coefficients of friction (COF) were the highest under the lowest normal load due to adhesion contributions. Interlocking between the smallest tip and the core-shell nanostructures (CSNs) resulted in higher COF on the textured surface than on the smooth DLC film. Larger counterface indenter tips experienced lower COF on CSNTS than on the smooth DLC film due to reduced contact area. Surface texturing was most effective in reducing the COF when the largest tip was used as the counterface.