Physical vapour deposition (PVD) is a well-known technology that is widely used for the deposition of thin films regarding many demands, namely tribological behaviour improvement, optical enhancement, visual/esthetic upgrading, and many other fields, with a wide range of applications already being perfectly established. Machining tools are, probably, one of the most common applications of this deposition technique, sometimes used together with chemical vapour deposition (CVD) in order to increase their lifespan, decreasing friction, and improving thermal properties. However, the CVD process is carried out at higher temperatures, inducing higher stresses in the coatings and substrate, being used essentially only when the required coating needs to be deposited using this process. In order to improve this technique, several studies have been carried out optimizing the PVD technique by increasing plasma ionization, decreasing dark areas (zones where there is no deposition into the reactor), improving targets use, enhancing atomic bombardment efficiency, or even increasing the deposition rate and optimizing the selection of gases. These studies reveal a huge potential in changing parameters to improve thin film quality, increasing as well the adhesion to the substrate. However, the process of improving energy efficiency regarding the industrial context has not been studied as deeply as required. This study aims to proceed to a review regarding the improvements already studied in order to optimize the sputtering PVD process, trying to relate these improvements with the industrial requirements as a function of product development and market demand.

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The machining process is still a very relevant process in today’s industry, being used to produce high quality parts for multiple industry sectors. The machining processes are heavily researched, with the focus on the improvement of these processes. One of these process improvements was the creation and implementation of tool coatings in various machining operations. These coatings improved overall process productivity and tool-life, with new coatings being developed for various machining applications. TiAlN coatings are still very present in today’s industry, being used due to its incredible wear behavior at high machining speeds, high mechanical properties, having a high-thermal stability and high corrosion resistance even at high machining temperatures. Novel TiAlN-based coatings doped with Ru, Mo and Ta are currently under investigation, as they show tremendous potential in terms of mechanical properties and wear behavior improvement. With the improvement of deposition technology, recent research seems to focus primarily on the study of nanolayered and nanocomposite TiAlN-based coatings, as the thinner layers improve drastically these coating’s beneficial properties for machining applications. In this review, the recent developments of TiAlN-based coatings are going to be presented, analyzed and their mechanical properties and cutting behavior for the turning and milling processes are compared.

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Micro-abrasion remains a test configuration hugely used, mainly for thin coatings. Several studies have been carried out investigating the parameters around this configuration. Recently, a new study was launched studying the behavior of different ball materials in abrasive particles’ dynamics in the contact area. This study intends to extend that study, investigating new ball materials never used so far in this test configuration. Thus, commercial balls of American Iron and Steel Institute (AISI) 52100 steel, Stainless Steel (SS) (AISI) 304 steel and Polytetrafluoroethylene (PTFE) were used under different test conditions and abrasive particles, using always the same coating for reference. Craters generated on the coated samples’ surface and tracks on the balls’ surface were carefully observed by Scanning Electron Microscopy (SEM) and 3D microscopy in order to understand the abrasive particles’ dynamics. As a softer material, more abrasive particles were entrapped on the PTFE ball’s surface, generating grooving wear on the samples. SS AISI 304 balls, being softer than the abrasive particles (diamond), also allowed particle entrapment, originating from grooving wear. AISI 52100 steel balls presented particle dynamics that are already known. Thus, this study extends the knowledge already existing, allowing to better select the ball material to be used in ball-cratering tests.

The automotive industry is a pioneer in solutions that meet market expectations. However, in the automotive industry, some less environmentally friendly technologies are still used, such as electroplating. Due to legislative restrictions in several countries, thin coatings made in a vacuum have been replacing coatings traditionally made by electroplating, mainly in decorative terms. This work is more focused on the use of these coatings made in vacuum for optical applications, namely on headlights and exterior backlit components. Although these components are protected during the period of use, there may be situations of contact during the assembly of the components or their repair, necessary to safeguard and to ensure that these coatings have the scratch and wear resistance needed to withstand any treatment deficiency during the operations referred to above. Therefore, this work is essentially focused on the study of the wear resistance of Cr coatings made by PVD (Physical Vapour Deposition) on polymeric substrates. To this end, the coatings previously studied have now been subjected to micro-abrasion tests, with a view to assessing their wear resistance. For this purpose, alumina abrasive has been used, and the wear mechanisms observed in the coatings were studied. The abrasion and scratch tests showed that the most stable film has the one provided with 10-layers, showing greater wear resistance as well, greater adhesion to the substrate and less cohesive failures in the performed tests. Given the nature of the substrate and the coating, the results obtained are very promising, showing that these 10-layer Cr thin coatings can overcome any careless operation during manufacturing, assembly and repair processes, when applied in lightning or backlit components in motor vehicles.