Surface Preparation Methods Research Articles

Effect of Pulsed Waterjet Surface Preparation on the Adhesion Strength of Cold Gas Dynamic Sprayed Aluminum Coatings

It has been observed that the method of substrate surface preparation can have a profound effect on the adhesion strength of cold-sprayed metallic coatings. In this investigation, pure aluminum powder was sprayed onto aluminum alloy substrates using cold spray. The substrates used in this work had undergone a variety of surface preparations to impart varying degrees of surface roughness. The pulsed waterjet technique was used to increase the substrates’ surface roughness beyond what can be achieved using traditional grit blasting procedures. Surfaces prepared using pulsed waterjet resulted in substantial increases in the pure aluminum coating adhesion strength. This increase may be the result of increased mechanical anchoring sites available as well as their favorable geometries. It is hypothesized that compressive residual stress may also contribute to increased adhesion strength.

The effect of materials and surface preparation on joining methods: A review

Materials have been the primary element of the structural community from the existence of ceramics to the more durable and efficient polymers. The uniqueness of these materials stems from a necessity of a particular era. Because of the uniqueness of each material, the study of damage is of key interest in materials research. In conjunction with the essential materials, proper joining techniques are also fundamental in infrastructure; however, joints represent one of the greatest challenges in the design of structures. Current forms of joining include mechanical and adhesive, where adhesive bonding is preferred. However, no joint can be properly designed without adequate surface preparation. Proper methods for surface preparation and joining techniques will be reviewed for composite materials. This review will highlight some of the common approaches used to enhance the strength of the joint and, therefore, the structure itself.

The Study Of The Impact Of Surface Preparation Methods Of Inconel 625 And 718 Nickel-Base Alloys On Wettability By BNi-2 And BNi-3 Brazing Filler Metals

Abstract The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240) on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

Fabrication of superhydrophobic surface with controlled adhesion by designing heterogeneous chemical composition

In this paper, a simple method for fabricating tunable adhesion superhydrophobic surface based on heterogeneous chemical composition was reported. By simply changing the ratio of HOOC(CH2)8COOH in the mixed modification solution, the slide angles (SA) of water droplet can be adjusted from extremely low (less than 10°) to very high (180°). Besides, the influence of surface chemical composition on the surface adhesion was also examined. Noticeably, the anti-corrosion performance of magnesium alloy was greatly improved after being modified. In addition, the tunable adhesion superhydrophobic magnesium alloy showed high hydrophobicity not only for pure water but also for corrosive liquids, such as acid, alkali, salt, cola, milk and coffee. Based on the great anti-corrosion performance and continuous adhesion, a proof of droplet-based microreactor and selective transportation of waters with different volume was provided. This study provides a new method for preparation of superhydrophobic surfaces with tunable adhesion, which not only offers the further principle for the fabrication of tunable adhesive superhydrophobic surfaces, but also can be potentially used in many important applications, such as micro-fluidic devices and chemical microreactors.

Cold upset forging joining of ultra-fine-grained aluminium and copper

This paper describes a study investigating joining copper, which is expensive but has excellent electrical properties, with aluminium, which is cheaper but is characterized by much worse mechanical and electrical properties. Metals with ultra-fine-grained structure were studied to understand the process of cold upset joining of hydrostatically extruded materials with a large deformation. Much greater difficulties were expected, based on the combination of conventional metals. The study verified the possibility of bonding such metals with various surface preparation methods and different parameters of the joint. The bond quality was checked by the static tensile test to study their tensile strength. To present the difference in joining conventional materials and ultra-fine-grained materials, was tested joining annealed copper and aluminium, and the results of this test were compared with tests for hydrostatically extruded material. The permanent joints were tested based on the hardness distribution across the joint and by observation of the fracture specimen's joints and EDS examination, which allowed us to determine that the connection mechanism does not rely on the diffusion of copper atoms to aluminium and vice versa.

Research in the Field of Manufacturing of Layered Brazing Materials

The results of research into manufacturing of layered brazing materials with silver brazing alloy BAg22 content and copper obtained in pressing at elevated temperature and rolling process for use in cutting tools working in harsh conditions were presented. Mechanical and dimensional properties of the constituent materials of the layered strips with 50 and 75% volume fraction of copper as the inner layer were selected, i.e. the BAg22 alloy strip and the copper strip, for the preliminary join operation in pressing process. Cladding process conditions of the set BAg22/Cu/BAg22 of the original thickness of 32mm for the ratio of layer thicknesses as 1:2:1 and 24mm of the original thickness for the ratio of layer thicknesses as 1:6:1 including the method of semi products surface preparation and range of forces and temperature parameters were specified. Plastic working conditions of pressed composite ingot in hot and cold rolling to the final thickness with the intermediate and final heat treatment parameters were developed.

The Study of the Impact of Surface Preparation Methods of Inconel 625 and 718 Nickel-Base Alloys on Wettability by BNi-2 and BNi-3 Brazing Filler Metals

Abstract The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240) on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

Airborne-particle abrasion parameters on the quality of titanium-ceramic bonds

Statement of problemAirborne-particle abrasion of titanium is a clinically acceptable method of surface preparation. It is crucial to know the effectiveness of bond strength between the metal substructure and the veneering ceramics after this kind of surface treatment. PurposeThe purpose of this study was to determine how the particle size of the abrasive material and pressure affected treated surfaces and the strength of titanium-ceramic bonds. Material and methodsDisks made of titanium (Tritan CpTi grade 1, Dentaurum, 99.5% Ti) were treated in an airborne-particle abrasion process with 50, 110, and 250 μm aluminum oxide (Al2O3) at pressures of 0.2, 0.4, and 0.6 MPa. To characterize the treated surfaces, the following values were measured: roughness, free surface energy, and the quantity of abrasive particles attached to the surface. Subsequently, the strength of the metal-ceramic bond was determined. Apart from the strength tests, fractures were observed to determine the character and fracture location in the course of the strength tests. The results of the experiment were analyzed with 2-way ANOVA and the Tukey HSD test (α=.05). ResultsBoth the pressure and the particle size of Al2O3 used in the airborne-particle abrasion affected the strength of the titanium-ceramic bond (P<.05). A statistically significant difference was found between the group subjected to airborne-particle abrasion under a pressure of 0.4 MPa with 110-μm Al2O3 particles and the other experimental groups (P<.05). ConclusionThis study demonstrates that the highest bond strength between a ceramic and titanium substructure can be achieved after airborne-particle abrasion at an angle close to 45 degrees with 110-μm Al2O3 particles under 0.4 MPa of pressure.

In situ strain and temperature measurement and modelling during arc welding

Experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well as a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.

Quantifying the effects of surface quality on texture measurements of tantalum

Surface quality plays an important role in texture measurements of the materials with high linear absorption coefficient. In this article, three different surface preparation methods were used and the effects of surface quality on texture measurements were quantitatively investigated. A bulk annealed tantalum was selected as a model material, whose surface was subjected to grinding, electropolishing and etching, respectively. In the case of the three surface states, macrotexture analyses were performed on an X-ray diffraction instrument and features of the surfaces were examined by optical microscope and surface profiler. Comparisons were made based on matching the percentages of two primary textures ({100}<uvw> and {111}<uvw>) obtained by X-ray diffraction (XRD) and electron back-scattering diffraction (EBSD) methods. It was revealed that states of sample surface, like roughness and damaged region caused by grinding, have a significant impact on texture results. Electropolishing was proved to be suitable for metals with high linear absorption coefficient for XRD texture measurements.

Interplay between surface preparation and device performance in CZTSSe solar cells: Effects of KCN and NH4OH etching

Despite the many similarities between Cu2ZnSn(S,Se)4 (CZTSSe) and Cu(In,Ga)(S,Se)2 materials and device architecture, open questions remain about the optimal surface preparation steps for CZTSSe absorbers, including whether differences exist for absorber layers deposited by different methods. In this work, we investigate KCN etching and NH4OH treatment as surface preparation methods for the absorber/CdS interface for two-stage processed CZTSSe and co-evaporated CZTSe absorber layers. Ambient-exposed, thus oxidized and contaminated, thin film absorbers are utilized to examine the effectiveness of these surface preparation methods and to elucidate their effects on device performance. Topography and surface potential images simultaneously obtained by Kelvin probe force microscopy (KPFM) show the existence of an overlayer on the ambient-exposed absorbers. Moreover, KPFM results also demonstrate that although NH4OH treatment removes much of the overlayer from the CZTSSe surface, KCN etching removes the overlayer completely. In addition, differences in the deposited CdS layer and depletion region width result depending on the surface preparation method, with the NH4OH-treated solar cells having narrower depletion region. This is reflected in device results in which KCN-etched solar cells outperform their NH4OH-treated counterparts due to increases in external quantum efficiency at long wavelengths and in open circuit voltage. KPFM measurements also demonstrate that grain boundaries (GBs) in the KCN-etched two-stage processed CZTSSe thin films are either negatively charged or neutral. On the other hand, KCN etching makes the surface almost equipotential in the co-evaporated CZTSe thin film by causing disappearance of positively charged GBs that existed before etching.

Influence of DC plasma modification on the selected properties and the geometrical surface structure of polylactide prior to autocatalytic metallization

The paper presents the results of studies to determine the applicability of plasma modification in the process of polylactide (PLA) surface preparation prior to the autocatalytic metallization. The polylactide plasma modification was carried out in an oxygen or nitrogen chemistry. The samples were tested with the following methods: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and electron spectrophotometry (XPS). Scanning electron microscopy and atomic force microscopy images were demonstrated. The results of surface free energy calculations, performed based on the results of the contact angle measurements have been presented. The results of the qualitative (degree of oxidation or nitridation) and quantitative analysis of the chemical composition of the polylactide surface layer have also been described. The results of the studies show that the DC plasma modification performed in the proposed condition is a suitable as a method of surface preparation for the polylactide metallization.

Shear-bond-strength of orthodontic brackets to aged nano-hybrid composite-resin surfaces using different surface preparation.

The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (p<0.001) between the groups. Sandblasted group had the highest SBS value (12.85 MPa) in experimental groups. The sandblasting surface treatment is recommended as an effective method of bonding orthodontic metal brackets to nano-hybrid composite resin surfaces.

The effect of bedding errors on the accuracy of plate load tests

During conventional plate load tests the stiffness of the ground is determined by measuring the settlement of a plate placed on the ground surface. If the contact between the plate and the ground is rough, bedding errors may occur during the test when plastic deformation occurs at the contacts between the plate and the ground. This paper addresses the effect of bedding errors on the accuracy of plate load tests. Three different surface preparation methods were investigated. In addition, a modified plate load test was designed to eliminate the effect of bedding errors that occur during these tests. Telescopic probes were used to measure the relative displacement at two points below the centre of the plate. The stiffness values, determined from the vertical displacement of the plate, were compared with the internal stiffness values determined by means of the telescopic probes. All stiffness values were compared with Continuous Surface Wave (CSW) measurements performed on the same material. The test apparatus, methods and results are discussed in this paper.

Effect of Different Polishing Methods on Anodic Titanium Dioxide Formation

Among various methods of synthesis of nanostructured TiO2, a self‐organized anodization is the most commonly used and discussed in the literature. However, different methods of pretreatment of Ti before anodic titanium dioxide (ATO) formation are not often addressed. Therefore, various polishing procedures based on mechanical, chemical, electrochemical, and combined electrochemical with chemical pretreatments were examined to establish whether they represent effective methods for smooth Ti surface preparation before anodization. The ATO layers were prepared via two‐step anodization carried out in an ethylene glycol solution containing fluoride ions at 20°C and under the anodizing potential of 60 V. The influence of applied polishing method on the cell size, pore diameter, pore circularity, pore density, and porosity of the top ATO layer was studied. In addition, the effect of polishing procedure on cell arrangement in ATO films was also investigated. The quantitative analyses of the regularity of cell arrangement, based on the regularity ratio derived from bottom‐view SEM images, showed that the type of polishing procedure does not affect the cell order.

Innovative Surface Preparation Method of Plastics Using UV Laser

Innovative Surface Preparation Method of Plastics Using UV Laser

Influence of surface preparation on fracture load of resin composite-based repairs.

The purpose of the present study is to evaluate the fracture load of composite-based repairs to fractured zirconium oxide (Z) crowns and to ceramic-fused-to-metal (CM) crowns, comparing different mechanical surface preparation methods. A total of 75 crowns were repaired; samples then underwent dynamic loading and thermocycling. Final fracture load values for failure of the repaired crowns were measured and the type of fracture registered. Group I: CM: Surface preparation with a diamond bur + 9.5% Hydrofluoric Acid (HF) etching; Group II): CM: air-particle (Al2O3) + 9.5% HF; Group III: CM: Silica coating (SiO2); Group IV): Z: air-particle (Al2O3) + HF 9.5%; Group V) Z: Silica coating (SiO2). Of the three CM groups, Group I (CM-diamond bur) showed the highest mean failure value, with significant difference in comparison with Group III (CM-silica coating). For the zirconia groups, the highest value was obtained by Group V (silica coating). Key words:Crown, ceramic-fused-to-metal, zirconia, resin-composite, ceramic covering.

Residual stress near single shot peening impingements determined by nanoindentation and numerical simulations

The near-surface hardness and residual stresses resulting from a single shot peening impingement on aluminum alloy 2024-T351 were assessed by nanoindentation with spatial mapping of mechanical properties on cross sections through an impingement. For residual stress, a procedure was developed to couple nanoindentation experiments with numerical simulations for better understanding and predicting the effects of shot peening. A surface preparation method was developed that exposes the cross section of a single shot impingement for nanoindentation tests, while at the same time obtaining accurate measurements of the impingement dimensions. Starting parameters for the numerical simulation in terms of shot diameter and the shot velocity were selected to best match measurements of the impingement depth and diameter. The experimental results indicated that the greatest hardness was located at the nearest indent to the peened surface, whereas the maximum compressive residual stress was located sub-surface. When comparing experimental and numerical residual stresses, the experimental results showed a greater maximum compressive residual stress that was in closer proximity to the peened surface. Overall, residual stress fields compared between experimental and numerical results were similar, and differences could be explained in terms of the effect of strain hardening. The current work demonstrated the usefulness of coupling nanoindentation experiments with numerical simulations for evaluating the surface modifications resulting from a single shot peening impingement.

Electronic states ofRFe2O4(R=Lu,Yb,Tm,Y)mixed-valence compounds determined by soft x-ray absorption spectroscopy and x-ray magnetic circular dichroism

We here report an investigation of the electronic states in the $R\mathrm{F}{\mathrm{e}}_{2}{\mathrm{O}}_{4}(R=\mathrm{Lu},\phantom{\rule{0.16em}{0ex}}\mathrm{Yb},\phantom{\rule{0.16em}{0ex}}\mathrm{Tm},\phantom{\rule{0.16em}{0ex}}\mathrm{Y})$ mixed-valence ferrites by means of soft x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements together with ab initio theoretical calculations. The presence of ${\mathrm{Fe}}^{+2}$ and ${\mathrm{Fe}}^{+3}$ pure ionic species is discarded in the XAS spectra at the $\mathrm{O}\phantom{\rule{0.16em}{0ex}}K$ edge in both experimental data and simulations based on the multiple scattering theory. Similarly, no trace of $\mathrm{F}{\mathrm{e}}^{+2}/\mathrm{F}{\mathrm{e}}^{+3}$ contributions is detected in the XMCD spectra at the $\mathrm{Fe}\phantom{\rule{0.16em}{0ex}}K$ edge. On the other hand, the XAS and XMCD spectra at the $\mathrm{Fe}\phantom{\rule{0.16em}{0ex}}{L}_{2,3}$ edges can be well described in terms of $\mathrm{F}{\mathrm{e}}^{+2}/\mathrm{F}{\mathrm{e}}^{+3}$ contributions, and are also supported by multiplet calculations. This finding can be interpreted as the existence of a mixture of $3{d}^{5}/3{d}^{6}$ configurations at the Fe atoms. Alternative ferrimagnetic spin orderings based on a trimodal Fe valence distribution are also proposed and discussed. Finally, a possible explanation for the strong dependence of the $\mathrm{Fe}\phantom{\rule{0.16em}{0ex}}{L}_{2,3}$ edges XMCD signal magnitude on both the sample surface preparation and detection method is presented.

Observation of Morphology Changes of Working Electrode during Cyclic Voltammetry by Using AFM

This article deals with the surface morphology changes of the lead-acid battery working electrode during the cyclic voltammetry measured by using AFM. At first it was tested several methods of surface preparation of lead plates used in the measurement. Cyclic voltammetry was performed. The measured values are shown in the relevant figures.