Effect Of Several Surface Treatments Research Articles

Tailored Interfaces in Fiber-Reinforced Elastomers: A Surface Treatment Study on Optimized Load Coupling via the Modified Fiber Bundle Debond Technique

The interface between the reinforcement and surrounding matrix in a fibrous composite is decisive and critical for maintaining component performance, durability, and mechanical structure properties for load coupling assessment, especially for highly flexible composite materials. The clear trend towards tailored solutions reveals that an in-depth knowledge on surface treating methods to enhance the fiber–matrix interfacial interaction and adhesion properties for an optimized load transfer needs to be ensured. This research aims to quantify the effect of several surface treatments for glass fibers applied in endless fiber-reinforced elastomers with pronounced high deformations. Due to this, the glass fiber surface is directly modified with selected sizings, using a wet chemical treatment, and characterized according to chemical and mechanical aspects. For this purpose, the interfacial adhesion performance between fibers and the surrounding matrix material is investigated by a modified fiber pull-out device. The results clearly show that an optimized surface treatment improves the interface strength and chemical bonding significantly. The fiber pull-out test confirms that an optimized fiber–matrix interface can be enhanced up to 85% compared to standard surface modifications, which distinctly provides the basis of enhanced performances on the component level. These findings were validated by chemical analysis methods and corresponding optical damage analysis.

Factors Affecting the Wear Behavior of Monolithic Zirconia and the Antagonists: Literature Review

Background:The use of zirconia-based ceramics to produce monolithic restorations has increased due to improvements in the optical properties of the materials. Traditionally, zirconiabased ceramics were veneered with porcelain or glass-ceramic and were not directly exposed to the oral environment. Therefore, there are several doubts regarding the wear of the monolithic zirconia restoration and their antagonists. Additionally, different surface treatments are recommended to promote a smooth surface, including glaze and several polishing protocols. To support the correct clinical application, it is important to understand the advantages and limitations of each surface treatment.Objective:The aim of this short literature review is to investigate the factors that may affect the wear of monolithic zirconia restorations in service and their antagonists.Methods:Pubmed/Medline database was accessed to review the literature from a 10-year period using the keywords: zirconia, monolithic, prosthesis, wear. Both clinical and in vitro studies were included in the review.Results:Studies investigated the effect of several surface treatments, including grinding with diamond- burs, polishing and glazing, on the surface roughness, phase transformation and wear capacity of monolithic zirconia. The wear behavior of monolithic zirconia was frequently compared to the wear behavior of other ceramics, such as feldspathic porcelain, lithium disilicate-based glassceramic and leucite-reinforced glass-ceramic. Human tooth, ceramics and resin composites were used as antagonist in the investigations. Only short-term clinical studies are available (up to 2 years).Conclusion:Literature findings suggest that zirconia monolithic restorations are wear resistant and unlikely to cause excessive wear to the antagonist, especially when compared to feldspathic porcelain and glass-ceramics. Monolithic zirconia should be polished rather than glazed. Yet, none of the polishing systems studied was able to completely restore the initial surface conditions of zirconia after being adjusted with burs. More clinical evidence of the antagonist tooth wear potential of monolithic zirconia is needed.

Surface treatments of plant fibers and their effects on mechanical properties of fiber-reinforced composites: A review

The need of natural fiber-reinforced composites is increasing at very fast rate because of their ecofriendly production, decomposition, high specific strength, abundance, good physical and mechanical properties. Available literature reveals that past researchers have done a lot of work for the preparation and characterization of fiber-reinforced composites. While developing natural fiber composites, researchers encountered various problems like hydrophilic nature of natural fibers, incompatibility of natural fibers with matrix materials, thermal instability of natural fibers, and poor interfacial bonding between reinforcing phase and matrix phase. However, some of these problems can be solved to a greater extent by considering surface treatment of natural fibers before they are used in the preparation of fiber-reinforced composites. Thus, there is a need for understanding the effect of several surface treatments on the mechanical properties of fiber-reinforced composites. The aim of this paper is to put forth a comprehensive review on the effects of different surface treatments on the mechanical properties such as tensile strength, flexural strength, and impact strength and also interfacial shear strength of the fiber-reinforced composites.

Adhesive bonding of carbon fibre/epoxy laminates: Correlation between surface and mechanical properties

The effect of several surface treatments on the surface properties (roughness and surface free energy) of carbon fibre/epoxy laminates has been analysed. Then, the adhesive joints of these treated laminates have been tested in order to determine their mechanical properties (shear strength and mode I fracture energy) and failure mode. It was found that the mechanical properties of the adhesive joints depend on the surface characteristics of the substrates. Several correlations were established, allowing the determination that mechanical interlocking is the main adhesion mechanism for the mode I testing, whereas the shear strength does not increase with a rougher surface. In fact, this property is directly correlated to the polar component of the surface free energy, indicating that in this case the main adhesion mechanisms are those influenced by the chemical composition of the surface. The best mechanical properties have been obtained when the failure mode was delamination of the substrates.

Evaluation of Surface Treatment Effects on the Tensile Strength of Piassava (Attalea Funifera) Fibers Using the Weibull Distribution

The effect of several surface treatments on the tensile strength of piassava fibers is discussed in terms of the Weibull statistical distribution. It is shown that the Weibull modulus can be used as an indicative parameter of the degree of surface structural modifications caused by the surface treatments, refining the results obtained by the LSD statistical test. SEM analysis was used to independently characterize the fiber surface structural changes caused by the treatments and corroborates the results inferred from the Weibull modulus.

The effect of surface variability factors on wind‐erosion susceptibility: A field study in SW Niger

AbstractThe effects of several surface treatments and factors that influence wind‐erosion susceptibility were measured with the means of a mobile wind tunnel. The test surfaces are situated in the SW part of the Republic of Niger in W Africa. The measurement program included the determination of total and dust‐mass fluxes and surface‐specific wind‐erosion parameters like aerodynamic roughness and friction velocities. Different treatments and variations were investigated on one typical and common sand surface type: different densities of stone cover, different kinds of millet‐residue alignments, and different topsoil humidities as well as the effect of different densities of fallow vegetation. The on‐site experiments in a controlled wind‐tunnel environment allowed the observation of effects that were only scarcely described in wind‐erosion literature. Increased stone cover resulted in increased emission due to increased turbulence and channelling effect, in spite of increased surface roughness. Millet‐residue alignment in transversal orientation to the wind direction resulted in far higher emission reduction as documented in the literature. Topsoil humidity, though far above the known threshold for erosion, could not completely inhibit particle entrainment because of the quick development of a thin superficial layer of dry particles.

Characterization of SiO 2 surface treatments using AFM, contact angles and a novel dewpoint technique

The properties of sensing surfaces are particularly important in chemical and biosensing since they affect the adhesion of sensing films and the sorption of analyte molecules onto the active area of the sensor. The objectives of this work were to study the effects of several surface treatments on glass and quartz using atomic force microscopy, contact angle measurements, and a novel dewpoint error technique, in order to develop a better understanding of the effects of these treatments. The dewpoint error technique was also examined as a novel method for measuring surface energy that may have advantages over contact angle measurements. Most significantly, chromic acid and oxygen/argon sputtering treatments were found to substantially decrease the contact angles of both glass and quartz. The surface roughness of glass was markedly increased by acetic acid, heated NaOH, and piranha etch while HCl and KOH caused the highest surface roughness for quartz. A reasonably good correlation was found between decreasing contact angles and increasing dewpoint error, suggesting that the dewpoint technique may provide a quantitative measure of surface energy without some of the drawbacks of contact angle measurements. There was no correlation found between surface roughness and contact angle hysteresis or dewpoint error.

Effect of hydrogen termination on the work of adhesion between rough polycrystalline silicon surfaces

A novel micromachined test structure has been used to measure the work of adhesion between polycrystalline silicon surfaces. The effects of several surface treatments, including a hydrogen- and an ammonium-fluoride-induced hydrogen termination and a hydrogen peroxide chemical oxidation, have been investigated with these test structures. A reduction in the average apparent work of adhesion by a factor of 2000 has been observed on the NH4F-treated surface compared to the oxide-coated surface. By using x-ray photoelectron spectroscopy and atomic force microscopy, the observed reduction is traced to the combined effect of the surface chemistry and topography. This work demonstrates that a hydrophobic, rough surface provides a significant reduction of the apparent work of adhesion in polysilicon micromachined devices.

Determination of surface recombination velocity and bulk lifetime in detector grade silicon and germanium crystals

The utility of a noncontact photoconductive decay (PCD) technique is demonstrated in measuring the bulk lifetime, /spl tau//sub B/, and surface recombination velocity, S, in detector grade silicon and germanium crystals. We show that the simple analytical equations which relate the observed effective lifetimes in PCD transients to /spl tau//sub B/ and S have a limited range of applicability. The noncontact PCD technique is used to determine the effect of several surface treatments on the observed effective lifetimes in Si and Ge. A degradation of the effective lifetime in Si is reported as a result of the growth of a thin layer of native oxide at room temperature under atmospheric conditions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of several surface treatments on xenon nuclear polarization and relaxation in optically pumped Rb-Xe systems

Effect of several surface treatments on xenon nuclear polarization and relaxation in optically pumped Rb-Xe systems