Effect Of Surface Pretreatment Research Articles

Effects of chemical surface pretreatment on tensile properties of a single glass fiber and the glass fiber reinforced epoxy composite

The aim of this article is to determine the effect of surface pretreatments, prior to the silanization, on the structure and tensile properties of the glass fibers and their epoxy composites. Commercial glass fibers were washed with acetone to remove the soluble portion of sizing, calcinated for the removal of organic matter, activated for surface silanol regeneration, and silanizated with glycidoxypropyltrimethoxysilane (GPS). Tensile test was carried out. The morphology of pretreated glass fibers and the fracture surfaces of the epoxy composites were observed with a scanning electron microscope (SEM). The results revealed that both apparent modulus and strength of a single glass fiber and the glass fiber/epoxy resin composites strongly depend on the fiber surface pretreatments. The acetone treatment did not change appreciably the composition and tensile properties of glass fibers, but there was a weak interface between fibers and matrix. In calcinated and acid activated fibers, the two competitive effects was observed: (1) degradation of the fibers themselves and (2) improved interfacial adhesion between the glass fibers and the epoxy matrix, once the samples was silanizated. The ATR‐FTIR results show that the surface content of SiOH increases as reflected by the increasing of the SiO band, resulting in an interaction between silane coupling agent and glass fiber. POLYM. COMPOS., 91–100, 2016. © 2014 Society of Plastics Engineers

Effect of surface pretreatment in the thermal atomic layer deposition of Al2O3 for passivation of crystal Si solar cells

H2O or NH4OH (5%) precursor pretreatment in the chamber was carried out before the thermal atomic layer deposition (ALD) of an Al2O3 passivation layer on p-type crystal Si. It was found that the density of negative oxide fixed charges significantly increased, the Al–O combination at the interface changed, the Al/O atomic at the interface of Al2O3/Si decreased, and the effective lifetime increased. The pretreated samples with changes in the Al–O structure at the interface, which made the interface more oxygen-rich, were believed to be the reason for the improvement of the field effect passivation in Al2O3 passivated crystal Si solar cell applications.

Surface pretreatment effects on titanium chips for the adhesion of pathogenic bacteria in the MALDI-TOF MS

Abstract The effect of surface pretreatment methodologies on subsequent oxide film formation and their surface properties is reported. The influence of hydrophobicity and hydrophilicity on the attachment/detection of pathogenic bacteria to titanium chip is also investigated. The results show that the Staphylococcus aureus preferred hydrophilic surfaces and also had an affinity for the non-heat treated (control) titanium surfaces. Laser ablation resulted in significant improvement in the attachment of both pathogenic bacteria. The bacteria attached to the modified titanium chips surface were analyzed by MALDI-TOF MS. Thus, this study demonstrates that modifying the surface by various surfaces pretreatment such as heat treatments and laser ablation could lead to selective capture of either Pseudomonas aeruginosa or Staphylococcus aureus by the titanium chips. This study is for direct and effective detection of pathogenic bacteria using MALDI-TOF MS.

A study of the effect of surface pre-treatment on the adhesion of coatings

This paper deals with the study of effects of mechanical surface preparation on the adhesion of coating with high content of zinc dust. Five kinds of mechanically blasted surfaces were studied. The following were used as abrasives: steel shot, steel grit, brown corundum oxide and zirblast. The last surface type was modified by MBX Blaster technology (mechanical bristle blasting). The surfaces topography was quantified by a roughness profilometer. The shape and size of the incurred inequalities on the modified surfaces were studied using 3D microscope images of the surface. The purity of the surfaces after pre-treatment was evaluated by impurity glued on the tape and measuring the reflection of light from the surface. Fractal analysis was used to evaluate the diversity of inequalities on the prepared surfaces. Cross-sections were also taken of the prepared surfaces. The prepared surfaces were coated with zinc-filled coating. The adhesion of the coating to the substrate was evaluated by a pull-off test after curing the coating (as sprayed), as well as after exposure to severe corrosive environments. The best adhesion of the coating was found for the coating applied to the substrate which had been pre-treated with brown corundum and steel grit.

Effect of surface pretreatment and pack cementation on bioactivity of titanium dental implant

The bone‐bonding ability of a material is generally assessed by examining the apatite forming ability in simulated body fluid. The bone‐bonding ability can be increased by increasing the surface roughness and forming a surface similar to the bone. In this study, pretreatments of titanium used for dental implant were anodized at a high voltage to form micropores, and at a low voltage to form nanotubes. In addition, pack cementation was performed on the pretreated specimens in a crucible filled with TTCP (tetracalcium phosphate) powder at 700°C for 24h to impart bioactivity.After pack cementation, apatite formed on the surface of all specimens. In particular, the amount of apatite was higher in the anodized specimens. The specimen immersed in SBF for one day was shown to form apatite on the entire surface due to the effect of anodic oxidation pretreatment of forming nanotube, thereby exhibiting the highest bioactivity. The surface roughness was significantly high in the anodized specimens (P<0.05), and the highest surface roughness was observed in the spark anodized specimen after pack cementation. The biocompatibility was good in all specimens that underwent the surface treatments, and cell differentiation and cell proliferation were activated the most in the nanotube‐anodized specimens after pack cementation. Therefore, strong bonding with the bone is expected as the surface roughness imparted by anodic oxidation results in an increase in implant surface area and corrosion resistance.Overall, the pretreatment and pack cementation are expected to be used for the surface modification of implant materials.

Effect of surface pretreatment on self-assembly of thiol-modified DNA monolayers on gold electrode

In this article we investigate the effect of gold pretreatment procedures on self-assembly of thiol-modified double-stranded DNA (ds-DNA) and single-stranded DNA (ss-DNA) on polycrystalline gold electrodes through cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), chronocoulometry(CC) and scanning electron microscopy(SEM). The pretreatment procedures include M+E, M+C(piranha), M+C(dilute aqua regia), M+C+E(piranha), M+C+E(dilute aqua regia) and RM+C+E(piranha), where M is mechanical polishing, C is piranha or dilute aqua regia dipping, E is electrochemical polishing and RM is roughly mechanical polishing. Results indicate that electrochemical characteristics (ions penetration, charge transfer and surface coverage) of ds-DNA or ss-DNA self-assembled monolayers (SAMs) on gold pretreated by different procedures except M+C(dilute aqua regia) are almost the same, although surface roughness and configuration of the pretreated gold electrodes differ. This conclusion differs from literature reports that pretreatment procedures have a big influence on the compactness of simple alkanethiols SAMs. We consider that the disagreement might be due to the special structural characteristics of DNA molecule, as compared with simple alkanethiols. The bigger size of DNA molecule and the existence of electrostatic or hydration forces among adjacent DNA molecules (Van der Waals force for simple alkanethiols) lead to the formation of sparse DNA-SAMs, which make much bigger selectivity for thiols adsorption sites on gold surface, therefore electrochemical characteristics of DNA-SAMs is almost independent of the pretreatment procedures. This work might provide a useful reference for constructing DNA-SAMs on gold.

Surface morphologies, tribological properties, and formation mechanism of the Ni–CeO2 nanocrystalline coatings on the modified surface of TA2 substrate

In order to remedy the poor tribological properties and low micro-hardness for pure titanium (TA2) materials, the Ni–CeO2 nanocrystalline coating was deposited from a Watts–Nickel electrolyte on the modified surface of TA2 substrate. In the present study, an available method of chemical activation was innovatively employed to make surface modification for TA2 substrate, in which the modified surface was characteristic of a rough surface and fully covered by the Ce-rich conducting phase for better electrodeposition. In order to study the effect of surface pretreatments on the modified TA2 surface, the surface roughness profiles and average roughness values were carried out using optical profilometry on the measured surfaces. A predictive modeling of TA2 surfaces before and after surface pretreatments was compared and successfully validated for better understanding of the formation mechanisms of electrodeposited Ni coatings reinforced with CeO2 nanoparticles. To clarify the beneficial effects of CeO2 addition on surface morphologies, phase composition, and textural evolution, the as-received nanocrystalline coatings were evaluated using various analytical techniques such as XRD, FE-SEM/EDX, and TEM. In addition, the scratch tests performed with an acoustic emission (AE) detector were conducted for the determination of interfacial adhesion between the as-deposited coating and the modified surface of TA2 substrate. Tribological properties and micro-hardness of investigated specimens were also examined. Experimental results revealed that this innovatively chemical activation was more favorable for increasing interfacial adhesion. The existence of well-distributed CeO2 phase that precipitated along the defective grain boundaries in the coating was contributed to make particulate reinforcement, thereby achieving better structural densification for Ni–CeO2 coatings. Meanwhile it exhibited superior tribological properties of the Ni–CeO2 coatings as compared to those of pure nickel and TA2 substrate, which was mainly attributed to the Ce-rich abrasive products that acted as a self-lubricating phase to make the effect of solid lubricants on worn surfaces.

A Comparison of N-Polar () GaN Surface Preparations for the Atomic Layer Deposition of Al2O3

Nitrogen-polar gallium nitride offers several advantages over Ga-polar GaN for high frequency-high power electronic devices, but its processing has not been fully developed. Here we report on a systematic study of the effect of surface pretreatments on N-polar GaN for metal oxide semiconductor capacitors (MOSCAPs). Bulk n-type GaN () substrates were prepared with a variety of treatments including: HF; HCl; base-piranha; H2 plasma; and no pretreatment for comparison. Then 14nm thick Al2O3 layers were deposited by atomic layer deposition (ALD). Both the original surfaces of GaN and ALD films were characterized by atomic force microscopy (AFM). MOSCAPs were fabricated and characterized by capacitance-voltage (C-V) and current voltage (I-V) measurements. The surface morphology and electrical performance was greatly affected by the pretreatments due to the reactive nature of N-polar GaN. The MOSCAP fabricated on GaN as-received with no additional preparation had the best performance including the smallest hysteresis (0.03V), lowest leakage current density (2.09 × 10−8 A/cm2 at +4V) and total trap density (2.47 × 1010 cm−2eV−1). This was correlated to the smoothest surface morphology (0.23 nm).

Effect of surface pre-treatment by silanization on corrosion protection of AA2024-T3 alloy by sol–gel nanocomposite coatings

Corrosion protection behavior of sol–gel coating doped with cerium nitrate was investigated on AA2024. The sol–gel layer composed of methyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane and colloidal silica. The performance of the sol–gel coating with and without surface silanization was evaluated using electrochemical techniques and neutral salt spray test. The morphology and composition of the coatings were examined by FESEM and EDX techniques before and after corrosion. Electrochemical studies indicated that cerium doped sol–gel coating with the additional APTEOS layer provided better corrosion resistance even after 168h of exposure among all the developed coatings. Surface silanization provided additional protection to the metal surface.

Effect of Surface Pretreatments on the Microtensile Bond Strength of Lithium-Disilicate Ceramic Repaired with Composite Resin

The aim of this study was to evaluate the influence of ceramic surface treatments and silane drying temperature on the microtensile bond strength (µTBS) of a resin composite to a lithium disilicate ceramic. Twenty blocks (7x7x5 mm) of lithium disilicate-based hot-pressed ceramic were fabricated and randomly divided into 4 groups: G1: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with room-temperature air; G2: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with 45 ± 5 °C warm air; G3: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with 45 ± 5 °C warm air; G4: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with air at room-temperature. After treatments, an adhesive system (Single Bond 2) was applied, light-cured and direct restorations were built up with a resin composite (Filtek Z250). Each specimen was stored in distilled water at 37 °C for 24 h and cut into ceramic-composite beams with 1 mm2 of cross-sectional area for µTBS testing. Statistical analysis was performed with one-way ANOVA and Student-Newman-Keuls test (α=0.05). µTBS means (S.D.) in MPa were: G1: 32.14 (7.98), G2: 35.00 (7.77) and G3: 18.36 (6.17). All specimens of G4 failed during the cutting. G1 and G2 presented significantly higher µTBS than G3 (p<0.05). There was no statistically significant difference between G1 and G2 (p>0.05). As far as the bond strength is concerned, surface pretreatment of lithium-disilicate ceramic with hydrofluoric acid and silane application can be used as an alternative to repair ceramic restorations with composite resin, while surface pretreatment with sandblasting should be avoided.

Effect of Surface Pretreatment on the Performance of Adhesive-Bonded Joints

This paper presents a systematic investigation of the influence of sandblasting pretreatment parameters on the surface roughness and mechanical characteristics of adhesive-bonded joints. The preliminary surface treatment in a bonding process has two important aims: first of all, it eliminates contaminants (dust, grease, humidity and corrosion products) which can modify the wettability of the substrate, then it increases surface roughness and, consequently, the contact area between substrate and adhesive, creating a mechanical interlocking that maximizes adhesion. To enhance the strength and avoid the de-adhesive failure of the joint, it is therefore advisable to increase the contact substrate-adhesive by a mechanical treatment of sanding, grinding or preferably sandblasting, usually considered one of the most effective methods to control the desired level of surface roughness and joint strength. This process, apparently easy to manage, is controlled by a great number of operating parameters, which all contribute to creating a good result. With the aim of evaluating the influence that some of these parameters have on the mechanical characteristics of adhesive-bonded joints, an experimental campaign was carried out. In particular, a steel substrate, an epoxy adhesive and various types of sand, different in nature and granulometry were used. The variable parameters for the execution of blasting are sand, impact angle and pressure. The assessments departed from an investigation into their effect on surface roughness and thereafter the mechanical properties of the bonded joints were analyzed.

The Undoped CVD Diamond Electrode: The Effect of Surface Pretreatment on its Electrochemical Properties

The Undoped <scp>CVD</scp> Diamond Electrode: The Effect of Surface Pretreatment on its Electrochemical Properties

Effect of surface pretreatments on the bonding strength and durability of self-adhesive resin cements to machined titanium

A durable and strong adhesive bond between luting agent and titanium framework is necessary. However, the nature of adhesion between titanium and the adhesive luting materials remains unclear. The purpose of this study was to evaluate the effect of treating surfaces with chemical etching solution on the adhesion of titanium-resin cement systems as determined by strain energy release rate (G-value, J/m(2)). One hundred and eighty commercially pure titanium (cp Ti) plates were prepared. The specimens were divided into 5 test groups according to the surface treatment used; Gr C (machined; control), Gr A (airborne-particle abrasion), Gr E15, Gr E30, and Gr E60 (experimental etching solution applied for 15, 30, or 60 minutes). For strain energy release rate testing, each group was further divided into 2 equal subgroups according to the type of resin cement used (i CEM or Multilink Speed). The strain energy release rate was evaluated after 24 hours of storage in distilled water or after thermocycling (10,000 cycles, 5°C to 55°C). The treated surfaces were characterized by AFM and SEM. Data were analyzed with ANOVA and the Tukey HSD test (α=.05). Strain energy release rate values were significantly affected by type of cement, surface treatment, and thermocycling (P<.05). After thermocycling, the cp Ti/i CEM (E30 and E60) groups showed the highest G-values among the groups. AFM and SEM analyses showed that the surface topography of cp Ti was modified after treatments. The strain energy release rate (G-value, J/m(2)) between resin cement and cp Ti can be improved by the use of experimental hot etching solution before cement application.

Influence of surface pretreatments on the corrosion protection of sol–gel coated AA2024‐T3 aluminium alloy

In the present study, the effects of surface pretreatments of AA2024 aluminium alloy on the corrosion protection of the alloy using a sol–gel coating were investigated. It was revealed that the second phase particles that remain after etching and desmutting have a significant impact on the subsequent sol–gel coating which, in turn, influences the overall corrosion protection afforded to the substrate by the sol–gel coating. The removal of second phase particles in the surface region can be achieved by an alternative surface pretreatment using nitric acid. A significant improvement of corrosion protection of sol–gel coated AA2024 aluminium alloy was observed when the surface of the alloy was pretreated with nitric acid. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Shear bond strength of one‐step self‐etch adhesives to enamel: effect of acid pretreatment

The purposes of this study were to evaluate the effect of surface pretreatment with phosphoric acid on the enamel bond strength of four-one-step self-etch adhesives with different pH values. One hundred bovine permanent mandibular incisors were used. The materials used in this study included four-one-step self-etch adhesives with different pH values: Adper(™) Easy Bond Self-Etch Adhesive (ph=0,8-1), Futurabond NR (ph=1,4), G-aenial Bond (ph=1,5), Clearfil(3) S Bond (ph=2,7). One two-step self-etch adhesive (Clearfil SE Bond/ph=0,8-1) was used as control. The teeth were assigned into two subgroups according to bonding procedure. In the first subgroup (n=50), no pretreatment agent was applied. In the second subgroup (n=50), etching was performed using 37% phosphoric acid for 30s. After adhesive systems application, a nanohybrid composite resin was inserted into the enamel surface. The specimens were placed in a universal testing machine (Model 3343, Instron Corp., Canton, Mass., USA). After the testing procedure, the fractured surfaces were examined with an optical microscope at a magnification of 10× to determine failure modes. The adhesive remnant index (ARI) was used to assess the amount of adhesive left on the enamel surface. Descriptive statistics of the shear bond strength and frequency distribution of ARI scores were calculated. Enamel pretreatment with phosphoric acid significantly increased bond strength values of all the adhesives tested. No significant differences in bond strength were detected among the four different one-step self-etch adhesives with different pH. Two-step self-etch adhesive showed the highest bond strength.

Electrochemical study of dsDNA on carbon nanotubes paste electrodes applying cyclic and differential pulse voltammetry

Abstract Abstract Carbon nanotubes paste electrodes (CNTPEs) in combination with adsorptive transfer stripping voltammetry are shown to be very suitable for the determination of calf thymus double-stranded DNA (dsDNA). The performance of three types of multi-walled carbon nanotubes paste electrodes (MWCNTPEs) is investigated. The effects of surface pre-treatment and accumulation conditions on the adsorption and electrooxidation of the dsDNA at MWCNTPEs are also described. The results indicate that the electroactivity inherent to carbon nanotubes/paste electrodes allows a large enhancement of the guanine oxidation signal compared to that obtained at the conventional carbon paste electrodes (CPEs). Moreover, the extent of the enhancement dependents on the type of MWCNTs incorporated into the paste. Based on the signal of guanine, under optimal conditions, very low levels of dsDNA can be detected following short accumulation times for all three types of MWCNTPEs (MWCNTPE1, MWCNTPE2, MWCNTPE3), with detection limits of 2.64 mg L−1, 2.02 mg L−1 and 1.46 mg L−1, respectively. Additionally, the dsDNA isolated from rat liver tissues is determined by use of the previously mentioned MWCNTPEs. Graphical abstract

Effect of surface pre-treatment on the hydrophilicity and adhesive properties of multilayered laminate used for lithium battery packaging

The surface of aluminum foil was treated using silane coupling agent and chromate–phosphate conversion solution respectively, then a flexible laminate consisting of five layers was prepared using polypropylene film as inner sealant layer and epoxy resin as adhesive between polypropylene film and aluminum foil. The surface morphology and composition of the foil after treatment were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and the hydrophilicity of the foil was evaluated by contact angle measurement (CAM). The adhesive strength between the aluminum foil and polypropylene film, and the heat sealing strength of polypropylene film were measured by tensile tester, their dependences on the surface treatments were further investigated. It can be concluded that the adhesive strength and heat sealing strength depend on not only the hydrophilicity, but also the morphology of the foil surface. The rough and porous surface of the treated foil can enhance both the adhesive strength and heat sealing strength.

Post-thermocycling shear bond strength of a gingiva-colored indirect composite layering material to three implant framework materials

Objective. To evaluate shear bond strength of a gingiva-colored indirect composite to three implant framework materials, before and after thermocycling, and verify the effect of surface pre-treatment for each framework. Materials and methods. Commercially pure titanium (CP-Ti), American Dental Association (ADA) type 4 casting gold alloy (Type IV) and zirconia ceramics (Zirconia) were assessed. For each substrate, 96 disks were divided into six groups and primed with one of the following primers: Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Activator), Estenia Opaque Primer (EOP), Metal Link (MLP) and V-Primer (VPR). The specimens were then bonded to a gingiva-colored indirect composite (Ceramage Concentrate GUM-D). Shear bond strengths were measured at 0 and 20 000 thermocycles and data were analyzed with the Steel-Dwass test and Mann-Whitney U-test. Results. Shear bond strengths were significantly lower after thermocycling, with the exception of Type IV specimens primed with CPB (p = 0.092) or MLP (p = 0.112). For CP-Ti and Zirconia specimens, priming with CPB or CPB+Activator produced significantly higher bond strengths at 0 and 20 000 thermocycles, as compared with the other groups. For Type IV specimens, priming with ALP or MLP produced higher bond strengths at 0 and 20 000 thermocycles. Conclusions. Shear bond strength of a gingiva-colored indirect composite to CP-Ti, gold alloy and zirconia ceramics was generally lower after thermocycling. Application of a hydrophobic phosphate monomer and polymerization initiator was effective in maintaining bond strength of CP-Ti and zirconia ceramics. Combined use of a thione monomer and phosphoric monomer enhanced the durable bond strength of gold alloy.

Effect of Surface Pretreatment on the Corrosion Resistance of Epoxy-Coated Carbon Steel

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting with different size, steel shot ball blasting and power tool treatment. To study the effect of the treatments, the topology of the treated surface was observed by optical 3D microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with hygrothermal cyclic testing. The results of EIS indicated that the epoxy-coated carbon steel treated with steel grit blasting showed an improved corrosion resistance compared to untreated epoxy-coated surfaces or surfaces subjected to shot ball blasting and power tool treatments.

Effect of surface pretreatment on corrosion resistance and bond strength of magnesium AZ31 alloy

A phosphate-permanganate surface treatment with additives Na2MoO4 and NaF was developed to improve the corrosion resistance and bond strength of magnesium AZ31. The phosphate coatings which have the magnesium phosphate, MgO, Mg (OH)2, MgF2 and a minor of Al2O3, Al(OH)3 Al0.35−0.55Si0.10−0.48P0.13−0.35O2.1−2.2 and, Al0.35Si0.48P0.18O2.2, and Al0.52P0.48O2.2 were formed on the surface of magnesium AZ31. A combination addition of the Na2MoO4 and NaF in the phosphate solution improves the corrosion resistance and bond strength of phosphated magnesium alloys. The optimal contents of NaF and Na2MoO4 are 0.8g/L and 0.5g/L, respectively.