Automotive Plasma Painting Process

Abstract

This study investigates the deposition of hydrogenated diamond-like carbon (DLC) films on SAE 1045 alloy samples using a plasma-enhanced chemical vapor deposition (PECVD) system and evaluates their potential as automotive coatings. Copper doping was performed via a hollow copper cathode to examine its effects on the DLC films. The primary focus was to determine the structural properties, color variations, and friction resistance of the coated samples, with the goal of establishing their applicability in the automotive industry. Raman spectroscopy confirmed the successful deposition of DLC films, while energy dispersive X-ray spectroscopy (EDS) analysis demonstrated the variation in copper atom concentrations in the samples based on the sputtering duration during the doping process. The observed color changes in the DLC films correlated with the copper atom concentrations, with the interference phenomenon and refractive index differences between DLC films and copper proposed as the primary factors influencing color variations. Scratch tests were conducted to evaluate the resistance to friction and delamination of the coated materials compared to conventionally painted steel samples. The results indicated that the DLC-coated materials exhibited higher resistance, with an estimated 15% increase in delamination resistance. The enhanced resistance was hypothesized to result from the high hardness of DLC films and the potential accumulation of nanoparticles in the valleys of the sample surface, reducing irregularities.