Analysis and study of industrially and technologically interesting surfaces

The document is organized into four main sections. The first comprises several "pieces of knowledge" collected over the years regarding topics I face in my research pathway. The remaining sections are devoted to scientific research tasks, reporting three main projects pursued during my Ph.D. career. The first one regard thickness gauging by X-ray spectrometric techniques. An innovative and cost-effective protocol for measuring electroplated coatings is proposed in this context. Our method relies on calibration curves based on self-produced standards. Specifically, it is reported that samples of suitable thickness distribution (consistent with certified standard specifications) can be obtained by dimensioning the cathode according to primary-only current distribution simulations. Then, by comparing different XRF quantitative methods, we demonstrate that our protocol is as effective as certified standards-based methods in accuracy but significantly lowers the cost. Section three explores the corrosion behavior of two types of electroplated white bronze coatings – Zn-bearing and Zn-free – in aqueous chloride media. Tests show that both materials protect the substrate (brass) against corrosion. However, Zn-free coatings have higher cathodic potential and perform better in environmental tests. We also study the effect of the coating thickness on corrosion phenomena, finding that the thicker the coating's thickness, the more cathodic the Open Circuit Potential (OCP). The effect of deposition methods on coatings' corrosion performance is investigated in the last section. The study has been carried out by comparing chromium coatings obtained by direct current electrodeposition and PVD Magnetron Sputtering. We present results of functional and aesthetical properties characterization for both types of coatings deposited onto copper substrates. Looking at electroplated samples as the benchmark, we found that Magnetron Sputtering preserves the eye-catching mirror-like finish imparted by metallic chromium, although exhibiting darker shades of grey. Scanning Electron Microscopy (SEM), investigations also evidenced that magnetron-sputtered coatings have superior thickness homogeneity and better surface morphology, lacking in submicrometer defects (voids and macrocracks) peculiar to electroplated samples. Regarding the anticorrosion performances, electrochemical and neutral salt spray tests carried out at room temperature in 3.5% NaCl solution evidenced similar or even better results for the magnetron-sputtered coatings. Overall, our findings support PVD Magnetron Sputtering as an industrially scalable technology for aesthetic and functional finishing processes.