Epoxy resins are widely applicable in industries such as aircraft, automobiles, coatings, and adhesives because of their good chemical resistance and excellent mechanical and thermal properties. However, on an external impact, the crack propagation of epoxy polymers weakens the overall impact resistance of the materials. Therefore, many impact modifiers have been developed to reduce the brittleness of epoxy polymers. Polyurethanes as an impact modifier can improve the toughness of polymers. Although it is known that polyurethanes are phase-separated in the polymer matrix after curing, connecting polyurethanes to the polymer matrix has been problematic for enhancing the mechanical properties of polymers. In this study, we introduced epoxy functional groups into polyol backbones, which is different from other studies that focused on modifying capping agents to achieve a network structure between the polymer matrix and polyurethane. We confirmed the molecular weight of the prepared polyurethane with gel permeation chromatography. Moreover, the prepared material was added to the epoxies to evaluate the changes in the mechanical and thermal properties of the materials. Furthermore, we conducted tensile, flexural strength, and impact resistance measurements. The experimental results are discussed in detail.

Stainless steel grade AISI 304 is one of the most widespread modern structural material, alas its sliding wear and cavitation wear resistance are limited. Thus, AlTiN and TiAlN coatings can be deposited for increasing the resistance to wear of stainless steel components. The aim of the work was to investigate the cavitation erosion and sliding wear mechanisms of magnetron sputtered AlTiN and TiAlN coatings deposited on SS304 stainless steel. AlTiN and TiAlN films were deposited on a stainless steel substrate grade AISI 304. Films surface morphology and structure were examined using a profilometer, light optical microscope (LOM) and scanning electron microscope (SEM). The mechanical properties (hardness, elastic modulus) were tested by nanoindentation tester. The adhesion of deposited coatings was determined by means of the scratch test and Rockwell test. Cavitation erosion tests were performed according to ASTM G32 (vibratory apparatus) with stationary specimen procedure. Sliding wear tests were conducted using a nano-tribo testes i.e. ball-on-disc apparatus. Wear mechanisms are strongly contingent upon the structure and morphology of the tested materials. In relation to stainless steel substrate, the PVD films present a superior resistance to sliding wear and cavitation erosion. Higher resistance was noticed for AlTiN than for TiAlN film, mainly due to its superior hardness and elastici modulus. Cavitation erosion mechanism of both, AlTiN and AlTiN coatings is prone to embrittlement, imputable to fatigue processes that result in coating rupture and spallation that consist in coating fragmentation, formation of pits and finally detachment from the substrate. In contrary to PVD coatings, steel substrate is characterized by developed cavitation erosion wear with roughened surface and plastically deformed, semi-brittle, eroded surface. Sliding wear of thin films is based on micro-ploughing mechanism. For stainless steel adhesive sliding wear mode and plastic deformation with smearing, material transfer and grooving were observed. It was confirmed that various fluid machinery components made from austenitic stainless steel that undergo cavitation erosion, can be prevented by deposition of AlTiN and TiAlN films.

Magnetron sputtering is a useful tool for producing coatings on various substrates at low temperature. The use of an austenitic stainless steel target in a nitrogen-containing plasma mixture allows to obtain nanostructured coatings with the formation of the so-called S phase, supersaturated interstitial solid solution of nitrogen in the expanded and distorted austenite lattice, which shows improved hardness and higher corrosion resistance in comparison with the bulk alloy. In the present research, RF magnetron sputtering deposition of austenitic stainless steel coatings using an AISI 316L target in nitrogen-containing plasma gas was studied. The effect of the N₂/Ar gas ratio and the deposition temperature on nitrogen content, phase composition and crystallite size is investigated by mean of XPS, XRD and electron microscopy analyses. The results show that the nitrogen content in the resulting deposit slightly depends on the N₂/Ar ratio in the chamber during the deposition, reaching a maximum value of about 35% with a 30% N₂/Ar gas composition mixture in the chamber. Data obtained on different substrates are presented and a preliminary evaluation of the corrosion resistance behaviour is also reported.

A car-roof photovoltaic has enormous potential to change our society. With this technology, 70% of a car can run on the solar energy collected by the solar panel on its roof.

Since it is to be accepted the majority of the customers, it should be painted as the normal car-painting. This paper estimated the energy yield loss by the automotive painting and setting the goal of the energy conversion efficiency with coated photovoltaic on the car-roof.

The estimation is not as simple as the spectroscopic transparency calculation but needs to consider angular weighting, the curvature of the panel, mismatching loss by the advanced multi-junction solar cells. To estimate the practical value of the target performance, we first monitored the PV module using three-junction solar cell (30 % efficiency) in outdoor for three years. We also developed the new energy yield model, because the conventional model only considers irradiance and temperature.

The newly-developed model successfully explained the seasonal trend of the energy yield of the spectrum-and-angular sensitive three-junction photovoltaic module. We also combined the ray-tracing simulation for consideration of the curvature of the car-roof. With the new and validated (by 3 years) energy generation model, we could define the target base PV efficiency for several car-painting, like blue, gold, red, green and grey.

Corrosion testing is a very important step in quality control for metal industrial processes. Especially for electroplated goods, corrosion resistance is a primary indicator of surface quality. International Standard Organization has established several standards that use Electrochemical Impedance Spectroscopy (EIS), alone or combined with other electrochemical techniques, to determine corrosion resistance of metal surfaces such ISO 16773 for testing coated and uncoated metallic specimens and ISO 17463 specially designed for organic-coated metal surfaces. EIS is a versatile procedure for the accelerated evaluation of the anti-corrosion performance of coatings: unlike other standard procedures is generally a non-destructive method. EIS works applying an electrical sinusoidal perturbation with a fixed frequency and measuring electrical impedance Z of the sample. Measuring impedance at different frequencies and analysing the data it is possible to postulate the structure of an equivalent circuit and extract corrosion resistance data. This approach is commonly used for high-impedance coatings, in this study we will explore EIS as well as the OCP measurement, the corrosion current and other techniques to find the best option for low-impedance metallic coatings analysis. The objective of this study is to develop a method to determine corrosion resistance for electroplated goods that can give results as reliable as other more diffuse and traditional destructive corrosion testing techniques (such as corrosion tests in artificial atmosphere ISO 9227 and ISO 17228) with a non-destructive process and in a fair less amount of time.