Different Types Of Surface Treatment Research Articles

Ribbed glass fiber reinforced plastic rebar embedded in concrete – an experimental study

The experimental program developed in this work aims at investigating the bond behavior of glass fiber reinforced plastic embedded in concrete. Different types of surface treatment were applied to the smooth rods in order to enhance the bond with concrete. Firstly, the rods were machined using a lathe and a grinding stone to create lugs with different configurations. The experimental results indicate that the bond strength is highest when the failure mode is a combination of two mechanisms: shearing off of the concrete lugs and that of the FRP lugs. With regard to the variation of rib width, the friction and interlock forces have a greater influence on bond strength. With respect to the height of the rib, the variation of internal diameter does not affect significantly the bond strength. Secondly, the machined rods were coated with sand fixed with a thin layer of epoxy resin. The incorporation of the sand on the surface increases the bond strength compared with the results obtained without sand.

Use of sand coating to improve bonding between GFRP bars and concrete

Glass fiber-reinforced polymer bars are currently used to reinforce concrete in an attempt to overcome the corrosion issue encountered with ordinary steel. Different types of surface treatment were applied to the smooth rods in order to enhance bonding with concrete. Experimental results show that using bars coated with coarse sand notably improve the bond strength. The influence of granulometry sand, rebar diameter, length embedded, and concrete strength are analyzed. Rebars coated with finer sand lead to a stronger chemical adhesion with concrete. However, the effect of friction and interlocking forces produced by coarse sand prevails over the chemical adhesion in the pull-out test.

Evidence of a bacterial carbonate coating on plaster samples subjected to the Calcite Bioconcept biomineralization technique

Degradation of historical buildings is mainly due to the intrusion of water which is the main vector of pollutants. Different types of surface treatment have been proposed to avoid or limit this effect. One alternative to chemical treatments is the use of the carbonatogenesis property of some bacteria. This bacterial production has been evidenced on concrete and on limestone samples in an aqueous environment. However, the carbonate production was measured indirectly and the experimental protocol was far from real conditions of use. In this paper, with the same protocol as an industrial one, and using a surface selective investigation method, grazing incidence X-ray diffraction, we show the structural and morphological evolution of the carbonate coating produced on model plaster samples. This substrate was chosen in order to unambiguously detect the bacterial carbonate production.

Liquid-phase deposition and the properties of thin zirconium dioxide films on different substrates

In recent years, the interest of the researchers to the methods of synthesis of inorganic thin oxide films from low-temperature liquid solutions permanently increases. This is explained by the recent achievements in the technology of deposition of the films, including, in particular, chemical deposition, sputtering, laser ablation, and evaporation. The liquid-phase deposition is an aqueous procedure of deposition of oxide films. In our investigation, we try to improve the adhesion and stability of zirconium-oxide coatings on polymers. Ceramic coatings (ZrO2) protect the surface of the substrate against reactions with acids and oxidation. The deposition of ceramic coatings on polymers is connected with serious problems due to the sensitivity of polymers to the action of chemical reagents and high temperature. We make an attempt to explain the role of the substrate in the process of deposition of zirconium-oxide films from the liquid phase on the Kapton polymeric material with different types of surface treatment. It is shown that even insignificant variations of the pH value, temperature, and composition of the solution can noticeably affect the crystalline film, adhesion, and growth rate. Thin films are very smooth, homogeneous, and characterized by the presence of an insignificant number of cracks.

Effect of surface pre-conditioning on bond of carbon fibre reinforced polymer rods to concrete

The experimental program developed in this work aims at investigating the possibility of using carbon fibre reinforced polymer rods to strengthen concrete structural members. Firstly, physical, chemical and mechanical tests were performed on carbon fibre reinforced polymer. Secondly, the bond between carbon fibre reinforced polymer rod and concrete was studied by using the pull-out test. Different types of surface treatment were applied to the smooth rods in order to enhance the bond with concrete. Firstly, the rods were machined using a lathe and a grinding stone to create lugs with different configurations. Secondly, the rods were coated with sand of various grain sizes. The sand was fixed on the rods with a thin layer of epoxy resin. The experimental results indicate that carbon fibre reinforced polymer rod seems to be a good option for strengthening concrete structural members. Results showed a very good physical, chemical and mechanical compatibility between the rods and the concrete. Depending on the surface treatment process, the ultimate bond strength can reach twice that of ribbed steel bars. Moreover, the residual friction between the carbon fibre reinforced polymer rods and the concrete (softening branch) remained equivalent to or greater than that of ribbed steel bar.

The use of angle resolved XPS to measure the fractional coverage of high- k dielectric materials on silicon and silicon dioxide surfaces

Angle resolved XPS (ARXPS) is a powerful tool for the determination of the thickness of ultra-thin films. In the case of high- k dielectric layers, the technique is capable of measuring the thickness of both the high- k layer and intermediate layers of silicon dioxide or metal silicate. The values for layer thickness are in close agreement with those generated by a variety of other techniques. As well as knowing the thickness of these layers, it is important to determine whether the layers are continuous or whether the coverage of the high- k layer is only partial. Using ARXPS, a method has been developed to determine whether the coverage of the high- k material is continuous and, if not, to calculate the fraction of the surface that is covered. The method is described with reference to the layers of Al 2O 3 grown on SiO 2 using atomic layer deposition (ALD). The method is then applied to HfO 2 layers produced using ALD on silicon wafers whose surfaces had received three different types of surface treatment. The way in which the layers grow and the nature of the resulting layer were found to depend upon the pre-treatment method. For example, growth on a thermal silicon dioxide surface resulted in complete coverage of HfO 2 after fewer ALD cycles than layers grown on an H-terminated surface. The results from ARXPS are compared with those obtained from ToF SIMS that have been shown earlier to be a valuable alternative to the LEIS analysis [1].

Enhancing the microstructure and properties of titanium alloys through nitriding and other surface engineering methods

Over the last 40 years, the commercial production of titanium and its alloys has increased steadily. Whilst these materials have some very attractive properties, enabling applications in many industries, they are seldom used in mechanical engineering applications because of their poor tribological properties. This paper starts with an introduction to the titanium material and a review of the different types of surface treatment. The processes of nitriding, oxidation and carburizing are among the most popular thermochemical treatments aiming at improving the surface properties of Ti-alloys. Different kinds of nitriding are investigated like plasma nitriding, ion nitriding, and laser and gas nitriding. The kinetics of nitriding and the conditions for the formation of nitrided layers are studied. The influence of the main processing parameters such as temperature, time on the microstructure and the formation of new phases during the processes of nitriding is discussed. Also based on investigations presented in the literature, the effects of nitriding on the microhardness and the corrosion resistance of titanium and titanium alloys are analyzed. The improved mechanical properties, which arise from these thermochemical treatments, are discussed in relation to the potential for applying these alloys to different industries.

Galvanic corrosion properties of differently PVD-treated magnesium die cast alloy AZ91

Different types of PVD coatings and plasma treatments were applied for the surface treatment of magnesium die cast alloy AZ91 specimens. The different types of surface treatment were all developed by the authors and the fundamental properties are described elsewhere. The coating systems were: • 9 μm CrN hard coating • 3 μm TiN coating • 0.5 μm plasma anodisation layer and 3 μm Al 2O 3 coating The wear and corrosion properties of the differently surface-treated AZ91 samples show crucial influence on the coating characteristics. While the well known metalloid CrN coatings show good wear properties due to high hardness and high coating thickness (9 μm), their corrosion properties are very poor due to crucial micro galvanic corrosion at coating defects. The plasma anodised and additionally Al 2O 3-coated specimens show good corrosion properties and are also prospective for tribological applications although their wear characteristics yet cannot reach the values for CrN-coated specimens. The publication shows the results of a novel immersion technique to determine the time dependent corrosion behaviour of coated magnesium alloys [B.L. Tiwari, J.J. Bommarito, Magnesium Technology 2 (2002) 269.]. Furthermore, the galvanic corrosion properties of differently coated AZ91 samples in contact with untreated AZ91, different aluminium alloys, roller bearing steel 100Cr6 and a titanium alloy TiAl 6V 4 were determined. The galvanic corrosion properties were tested according to DIN 50019.

Effect of different types of surface treatment on the photoelectric and optical properties of CdTe

The photoconductivity and light absorption spectra of p-type CdTe single crystals subjected to different treatments have been investigated. It is shown that the photoconductivity and edge absorption in mechanically polished and plastically deformed crystals are determined by the damaged layer. The role of dislocations in the formation of the edge absorption and the photoconductivity spectrum is determined.

The influence of surface defects on high-cycle fatigue of engineering materials

An investigation was performed on the influence of surface defects, such as indentor's imprint, etching pits, and nonmetallic inclusions, upon high-cycle fatigue of alloyed steel 20Kh13, carbon steel 20, and titanium alloy VT3-1 in torsion and rotational bending. Defects were initiated on the surface after its polishing, grinding, and surface plastic deformation. The analysis of the results obtained involved the use of the theoretical stress concentration factor values and the magnitudes of residual stresses in the surface layer after different types of surface treatment, as well as residual stresses generated by the introduced defects. A method has been substantiated for predicting the influence of defects on fatigue limit taking into account the defect area.