Tribological and corrosion performance of DLC coating on sintered Al alloy

DLC formation on sintered Al alloys and its purity is obtained for automotive applications. In this work, initial evaluation of DLC coatings was performed using scratch, micro-hardness, fracture toughness and surface roughness tests on sintered Al. Raman spectra analysis confirms the DLC formation. The DLC coated sintered Al samples exhibits micro-hardness in the range of 2000 to 2300 kg mm⁻² when measured using a Vickers diamond pyramid indenter of 0.5 N load applied on it. In some localized regions, even more hardness (>5000 kg mm⁻²) has been obtained. Scratch test results shows a fairly homogenous coating with strong adhesive nature having almost four times the average critical force compared to electro-statically deposited sample. Fracture toughness and surface roughness are well within the acceptable ranges of DLC coatings. The capability of laser sintering to produce thick DLC coatings with outstanding mechanical and tribological properties and excellent bonding with aluminium offers the possibility to tailor an extreme lightweight, strong and wear-resistant material. Nano indentation result indicates the information of plastic and elastic deformation for industry based applications. (paper)