Papers by Keyword: Surface Treatment

Abstract: A rapid repair process of plasma damaged SiCOH in combination with post-etch residue removal has been developed. The carbon depletion layer caused by plasma dry etching was repaired by subsequent surface modifying SAM treatment, which resulted in replenishment of carbon not only on the surface but also a few nm toward the bulk. This repairing technique provides a high-quality hydrophobic surface under conditions of low temperature and short process time. In addition, the SAM layer can be expected to act as an adhesion promotor with metal materials.

Abstract: This work proposes the development of a niobium phosphate coating (PNb) to replace the zinc phosphating, which is very aggressive to the environment and human health. The metallic material utilized was carbon steel (SAE 1010), which was coated with sunbathing - gel containing phosphate and niobium. A traditional zinc phosphate coating was used for comparison of results. The samples were characterized by scanning electron microscopy (SEM), dispersive energy spectroscopy (DES), open circuit potential, electrochemical impedance spectroscopy and anodic polarization. The results demonstrated that the samples coated with niobium phosphate have more surface nobility and greater corrosion resistance.

Abstract: Some metals prior to receiving a layer of paint should be submitted to a treatment of metal surface, since they are subjected to corrosion. This work aims the obtaining and characterization of a coating based on ceramics of cerium and / or zirconium for metal surfaces treatment. The ceramics were obtained by immersing the aluminum alloy 3003 and the carbon steel (SAE 1010) in the polymeric resin of citric acid and ethylene glycol according to the Pechini method. The characterization of the samples was performed using the following techniques: scanning electron microscopy (SEM), open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and Potentiodynamic Anodic Polarization (PAP). It was confirmed that the coatings of cerium and / or zirconium presented themselves as promise in the treatment of metal surfaces, because both showed good resistance, protecting the metal from corrosion.

Abstract: Low temperature plasma, compared to liquid phase treatment, can effectively overcome the environment pollution, high energy loss and high cost as its high activity. The low temperature plasma, which is not only fairly friendly to the environment but also of less resource consumption, also can realize the cleaning, activating and grafting treatment for materials surface. Based on the numerical model of CRFHCP (Capacitive Radio Frequency Hollow Cathode Plasma) hollow cathode plasma discharge, the key point to affect plasma discharge was analyzed and the morphology of PP film before and after hollow cathode plasma discharge was analyzed. The results showed that the structure of plasma hollow cathode discharge can effectively improved the chemical behaviors of PP film.

Abstract: Rice husks (RH) are characterized by a high content of silicon dioxide up to 23 wt. %. Silica in the form of nanoparticles creates surface layers formed in various plant parts which ensure protective properties and mechanical stability. These nanoparticles with a dimension in the range of tens of nanometers, are formed during biochemical processes and photosynthesis. Individual nanoparticles are interconnected between themselves and between layers with organic phase via cellulose fibres. Accompanying ions mainly potassium, calcium, sodium, magnesium and aluminium extremely important for plant growth have also been identified in rice husks. In this research paper we investigated mechanical properties of composite epoxy resin material, which was composed of ChS Epoxy 520 filled with silica obtained from rice husks. Nanoparticles of silicon dioxide with the size in dozen of nanometers were prepared by calcination of raw plant parts. We found that the 0.1 phr of filling (0.01 g of filler + 10 g of epoxy) demonstrated a significant increase of wear resistance and decrease of coefficient of friction. An excellent adhesion between epoxy resin and silica nanoparticles was also observed. The silicon dioxide in epoxy resin plays the role of the hard phase, which transfers part of the load and protects the surface of polymer against wear. The presence of this filler does not change the mechanical properties of the original resin.

Abstract: Surface protection by hydrophobic impregnation and surface coating are widely used for concrete bridges located at coastal area in Japan. This paper deals with the improvement of adhesion between surface coating and hydrophobic impregnated concrete by different types of silanes and by invastigating surface treatment methods. As a result, adhesion between hydrophobic impregnated concrete and epoxy-based surface coating were improved by applying abrasive paper, portable electric grinder, solvent or diluted hydrochloric acid treatment. Especially, using portable electric grinder gave a remarkable improvement to the adhesive property. Also, hybrid-surface protection system consisting of surface coating and hydrophobic impregnation was discussed to prevent blistering.

Abstract: The problem of punching tools resistance increasing is investigated. Methods for intermetallic coatings synthesis are investigated. Mathematical model of vacuum ion-plasma deposition process allowing predicting coatings composition basing on intermetallic system Ti-Al was developed. Experimental verification confirmed the adequacy of the computer model. The technology hardening punching tools with wear-resistant coatings deposition based on intermetallic Ti-Al system on pre-nitriding surface in vacuum was developed. Production tests of the hardened punching tools were carried out.

Abstract: This study aims to investigate the properties of CDW recycled aggregates using silane-based water repellent agent in three different types of treatments: (a) immersion; (b) sprinkling; and (c) dripping; in order to improve the reduces quality of the material due to the high porosity. Wettability and water absorption were determined by apparent contact angle measurements, water absorption after 24h of saturation (standard method) and recording the variation of submerged mass during 24 hs. All treatment allowed reducing the water absorption and its kinetic. The contact angle measurements confirmed the effectiveness of the treatment: the surface resulted always hydrophobic. Comparing the treatments, immersion gave the best result in terms of absolute results and in terms of variability of measurements.

Abstract: Micro-arc oxidation technology is a new type of metal surface treatment technology. With a large area of die casting magnesium alloy wheel surface treatment as an example, the practical production and application of micro-arc oxidation technology of magnesium alloy is discussed, Surface treatment technology production line is designed, The main equipment and process piping required for production line is introduced in detail. By the study of current and voltage which have a large effect on the craft of micro-arc to magnesium alloy, in the end a kind of electric parameters of micro-arc oxidation about magnesium alloy was optimized and film quality for testing. The micro-arc oxidation technology has been proved practically an appropriate technology for Mg alloy wheel hub and reference for the mass production used for a large area of magnesium alloy surface treatment technology and equipment design.

Abstract: Magnesium alloy which is one of the least light density (about1.7g/cm³) composites material on the ground for trade business, this material has better strength ratio of room temperature, high strength and rigidity, with good vibration attenuation, better damping, and good heat conduction,resistant radiation, don’t produce spark when friction, good ductility, better cutting machine and formed possibility, may be welded, adhesives, and have good chemical stability to Alkali, kerosene, gasoline, mineral oil and dry atmosphere, With no magnetic and electromagnetic shielding properties, Magnesium alloy products easy to recycle and no pollution to environment etc. Known as in twenty-first century the "green engineering materials”, In order to improve the use range of alloy,it need for improved performance of AZ31 magnesium alloy, AZ31 magnesium alloy surface modification technology to solve the main problems is to reduce the cost and environmental issues of a single technology, There is a wide prospect for the application of compound modification.