Papers by Keyword: Surface Treatment

Abstract: Steel constructions are an integral part of our lives, surrounding us almost everywhere. They are used for erection of various halls, bridge structures, railings etc. Each steelwork is more or less impaired by corrosion, respectively a certain level of corrosion aggressiveness of the environment. Corrosion is the cause of material degradation - referred to rusting. In order to avoid this unwanted phenomenon to the maximum extent possible, we use various methods and technologies protecting the relevant material and preventing from corrosion occurrence and development. This article deals with one of the methods aimed at corrosion protection of structural steelwork - duplex coating system that is assured by means of hot dip galvanizing followed by paint system application.

Abstract: In this investigation surface treatment of titanium alloy VT20 is carried out by phosphating and anodization in order to increase the adhesive bond strength. The surfaces were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), profilometry, contact angle measurements. The joined titanium specimens were shear tested before and after exposure to high humidity to a period of three months.

Abstract: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties, thickness and structure of an anodic layer formed on aluminium casting alloys. Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT, abrasive wear test was made with using ABR-8251 equipment delivered by TCD Teknologi ApS and microstructure investigations were made with using a light microscope equipped with an electronic camera configured with a computer on two casting aluminium alloys which both were founding by pressure die casting and gravity casting. The researches included analyse of the influence of chemical composition, geometry, roughness and abrasive wear resistant of anodic layer obtained on aluminium casts.Research limitations/implications Contributes to research on anodic layer for aluminium casting alloys. Practical implications Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodisation process of aluminium casting alloys, e.g. in the range of raising resistance on corrosion. Originality of this research was to describe the range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.

Abstract: The coupled model is presented to describe the elements penetration into the surface layer of metal during the process of ion implantation. Mechanical stresses arising due to the interaction of particles with the surface affect the redistribution of the implanted impurity. In addition, the existence of vacancies in the metal surface and their generation under the stresses influence are taken into account. The kinetic law is written on the basis of the thermodynamics of irreversible processes. The solution had been found numerically. As a result, the distributions of impurity concentration and deformations have been obtained for various time moments. The comparison of the concentration profiles with vacancies and without their have been given.

Abstract: It is well known that titanium (Ti) has excellent properties of anticorrosion, biocompatibility and low modulus that would be applied in many clinical applications. The aim of this study wants to increase the hydrophilicity of titanium surface through silanization and then grafted with hydroxyapatite (HA) by hydrothermal synthesis method. Physiochemical analysis of grafting plate substrate was observed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and contact angle analysis. The surfaces with silanization were strongly interaction between SiO₂ and TiO₂, and thus Ti-O-Si-bonds formed having larger surface areas but only showed a little improved hydrophilicity. The hydrophilicity of Ti substrate was largely increased after the hydrothermal process. Compared with Ti surface without any surface treatment, the surface which modified with hydrothermal synthesis can improve the wettability of Ti surfaces. Furthermore, the Ti surface through silanized modification before hydrothermal synthesis held good calcium phosphate precipitates existing due to the better calcium ion combined ability with polar bond of aldehyde group (Ti-O-Si-CO^-).

Abstract: Silane film technology is an energy saving and environment-friendly metal surface treatment technology.The best hydrolysis condition of mixed Bis[3-(trimethoxysilyl)propyl]amine(BTSPA) and Vinyltriethoxysilane(VTAS) are studied by orthogonal experiments in this paper.The corrosion resistance of the film formed under optimum conditions in 0.5M NaCl solution was studied by Potentiodynamic polarization curves and electrochemical impedance spectroscopy.The studies show that the optimal hydrolysis conditions: silane content is 8ml, alcohol -water ratio is 80:15, pH value is 4.0, hydrolysis temperature is 25 °C.Silane film formed on cold-rolled steel has good corrosion resistance in 0.5M NaCl solution.

Abstract: The fiber metal laminates have a wide range of applications today, owing to its high-performance and light weight. However, the interface properties between the fiber face sheet and metal substrate are weak and there are differences in their mechanical properties, causing structural damage or failure. Therefore, this article has come up with a new way to enhance the bonding strength. Through the mechanical methods to get different surfaces, choosing Ra as the evaluating parameter. By conducting the mechanics tests of each specimen, the results showed that with the rising of the Ra, the maximum load of the specimen was rising, too. But the trend wasn’t always the same. After the best Ra, the load declined and kept steady. So, in a small range of roughness, the leading role of bonding strength is the surface of the metal, otherwise, the leading role is the surface of fiber face sheet.

Abstract: A slow strain rate tensile (SSRT) test was used to investigate the effect of laser shock peening (LSP) on stress corrosion cracking (SCC) behavior of the 304 austenitic stainless steels (ASSs) in acid chloride solution. Mechanical properties and fracture morphology evolutions of the 304 ASSs were studied as a function of the pulse energies through slow speed tensile tester and scanning electron microscopy (SEM). The results showed that the percentage elongation after fracture increased significantly as the pulse energy rose. Fractographic examination revealed that all the samples appeared a tendency to SCC in the given conditions, but specimens treated by LSP had better resistance to stress corrosion.

Abstract: Poly p-phenylene benzobisoxazole (PBO) fiber is a kind of organic fiber with high performance, but the properties of the interface between PBO fiber and resin are poor, which limit its application in the field of composite materials. Therefore, the surface modification methods were employed to enhance the interface properties, which could damage the fiber. This article assessed the influence of plasma modification, γ-ray irradiation, coupling agent, acid treatment and combined treatments on the strength of PBO fiber filament, and investigated its tensile strength with Weibull analysis. Through observation of fiber surface by SEM，it can be found that some combined treatments caused less damage to PBO fiber compared to the individual treatments. This indicates that if combining the different treatments appropriately, the interface energy of PBO fiber will increase, with the excellent mechanical properties well retained

Abstract: In order to improve the interfacial properties in carbon fiber (CF) reinforced epoxy (EP) composites, we directly introduced amidized carbon nanotubes (CNTs) dispersed in the fiber sizing onto the fiber surface. Morphology and surface energy of CFs were examined by scanning electron microscopy (SEM) and dynamic contact angle analysis test (DCAT). Tensile strength (TS) was investigated in accordance with ASTM standards. Mechanical properties of the composites were investigated by interlaminar shear strength (ILSS) and impact toughness. Test results indicate that TS, ILSS and impact toughness were enhanced simultaneously.