Produção de filmes DLC via deposição por plasma com cilindros catódicos

Abstract

This study involves the deposition of diamond-like carbon (DLC) thin films on AISI 4340 steel by thermochemical treatment, using the plasma deposition technique with cathodic cylinders (CCyPD) in a plasma reactor. This technique involves using a support cage for the compacted powder cylinders, developed as a new variation of the cathodic cage deposition technique. The objective is to produce DLC films through the CCyPD technique with high hardness and good tribological behavior to enhance the resistance and lifespan of AISI 4340 steel. The cathodic cylinder was produced with graphite powder and compacted with a load of 2 tons in a hydraulic press. Treatments were performed using different proportions of argon (Ar) and acetylene (𝐶2𝐻2) gases for a period of 4 hours, under floating potential, using an alumina disc. The characterizations of the deposited films were studied by X-ray diffraction (XRD) to determine the phases, and Raman spectroscopy for the chemical composition of the film. To quantify the surface hardness and coefficient of friction, Vickers microhardness and pin-on-disk tests were performed. After the pin-on-disk test, a portable roughness meter was used to profile the wear track. The results showed adequate DLC film characteristics, such as the presence of carbon and diamond phases in XRD, D and G bands in Raman spectroscopy, high surface hardness, and low coefficient of friction, contributing to the increased lifespan of AISI 4340 steel.