scratch resistance of paints degraded by arid saharan environments

In the vast algerian sahara, the climate is typically desert, characterized by heat and dryness all year, which contributes to a very pronounced aridity. the aim of this study is to investigate the impact of this arid environment on automotive paints. four paint samples with different durations of use were tested. initially, a visualization of the surface condition by optical microscopy and microhardness tests was used. then, microscratch tests with a progressive loading at a constant sliding speed were carried out to determine the adhesion of the paints. the obtained scratches were analyzed by scanning electron microscopy (sem). the results show that the microhardness and microscratching resistance of the paints increased to maximum values corresponding to duration of five years. beyond this duration, an inverse tendency of these characteristics was observed. compared to the three years sample, the microscratch of this one leads to damage without the delamination of the paint.