Surface Of Substrate Material Research Articles

Multilayered conductive gradient framework for stability high Mass-Loading Lithium metal battery

As a result of the affinity and inadequate ability to regulate Li+, Li metal tends to accumulate on the surface of substrate materials, which reduces space utilization and promotes dendrite growth. Especially since the flow of Li+ toward the substrate’s bottom can be tricky to control, high mass-loading is a challenge for the traditional framework design. Herein, inspired by a tree root network, a cellulose-based gradient framework was designed for the Li metal anode. Bacterial cellulose-doping carbon-coated zinc oxide (ZnO@C) nanoparticles are used for decorating the top, and ZnO@C nanoparticles placed on Cu foil decorate the bottom. Owing to the gradient conductivity, Li deposition can be directed from the bottom to up to obtain sufficient unoccupied space accommodating volume changes and fully utilize the entire frame to achieve high mass-loading. Moreover, the transportation of Li+ is facilitated by the spontaneous formation of the LiF/Li2CO3/LiOH-enriched SEI layer, which has an exceptional ability to conduct ions. As a result, a 3000 h lifespan with an average coulombic efficiency of 98% was achieved. Notably, LiFePO4 full cell exhibits excellent cycling stability and high energy density (102 mAh/g) under realistic conditions (negative to positive capacity ratio as 1.75).

Development of an Oxide Layer on Al 6061 Using Plasma Arc Electrolytic Oxidation in Silicate-Based Electrolyte.

The plasma electrolytic method is one of the techniques which can be used to form an oxide layer on the substrate material surface. This technique employs ion exchange by developing an electrolytic arc between the cathode and the anode. The strong bond at high temperatures promotes the formation of an oxide layer on the metal surface. The electrolyte composition has a strong influence on the metal surface characteristics. Hence, the addition of certain nanoparticles in an adequate amount can improve the surface properties like wear and corrosion resistance. In this study, a plasma electrolytic technique based on using a direct current and voltage approach is investigated. The plasma electrolytic technique is utilized to develop an oxide layer on the Al 6061 alloy substrate surface using a DC voltage input on a silicate-based electrolyte. The substrate surface is then investigated for the thickness of the oxide layer formed and the amount of carbon element absorbed, using the SEM and XRD analysis. The experimentation and the study of the results confirmed the presence of a substantial oxide layer on the surface. The influence of the process on the output parameters-direct voltage and electrode distance is studied with the significant changes obtained in the weight percentage of elements like C, Al, Si, and O as supported by SEM and EDAX analysis. Most changes occurred when using a 197 V and in the current range of 0.3 A to 1 A. This can be useful further to improve the mechanical properties of the metal alloy using the plasma arc oxidation method.

Examining the influence of shoulder to pin diameter ratio on corrosion behavior of friction stir LM25 aluminum alloy with 10% silicon carbide particles

Friction stir processing (FSP) is a unique method that facilitates the generation of frictional heat between the tool and the workpiece. Stir casted LM 25 aluminum alloy-10% SiCp Metal Matrix Composites (MMC) consists of large aggregated strengthened particles and cast item dendrites. In FSP, a non-consumable instrument made of harder material plays a crucial part in changing the substrate material's surface. In the present study, an attempt has been made to analyze the impact of different ratio of shoulder diameters to pin diameter (D/d) on the immersion corrosion conduct of the LM25AA processed friction stir – 10% SiCp MMCs. The size and dispersion of SiC particles in friction stir processed (FSPed) MMC were studied. The microhardness and tensile characteristics of the FSPed material were assessed and associated with the micro and macro structures. The influence of D/d ratio on the microstructure, micro-hardness, and corrosion rate was analyzed and observed that the hardness and rate of corrosion increase with the decrease in grain size of the matrix and SiC particles.

Gradient composite coatings on AA5754 using friction stir process

ABSTRACTIn this paper, a substrate material (AA5754) was coated using a consumable rod/coating shaft (AA7075) as both a single layer and gradient layers by friction stir process. The order of the gradient coating process can be listed as; mixing the Al + TiC powders, pressing inside the consumable rod, sintering at certain temperatures and coating the substrate material surface with three overlapping layers at different reinforcement ratios. Microhardness and wear tests were performed to investigate the mechanical properties of the coatings. The microstructures of the coated materials have been examined by using optical microscope and SEM. The EDX and XRD analyses were also applied to the new-coated materials. The shaft rotational speed had a significant effect on the microstructure in the friction coating which was performed at single layer and in a powder-free fashion. The gradient ratio in gradient coatings had a considerable effect on the hardness and wear resistance.

Analytical model of friction behavior during polymer scratching with conical tip

To investigate the effects of the contact geometry, interfacial friction, and substrate recovery on the behavior of polymer scratching using a conical tip, an analytical model is proposed. The normal stress acting on the contact surface between the tip and the substrate is described as a function of the included angle θ, representing the angle between two planes across the axis of the conical tip, and the attack angle β, representing the angle between the conical surface and the substrate material surface. The effects of the rear contact geometry on the scratch friction between the tip and substrate, represented by recovery angle φ, owing to the instantaneous elastic recovery of the polymer substrate, are also introduced. Validated by the experimental and numerical results from the literature, the proposed analytical model can describe well the scratch coefficient of friction (SCOF), which is defined as the ratio of the tangential force to the normal force. Meaningful guidance is provided to understand the scratch friction behavior.

Characterization of Fe–C–Cr Based Hardfacing Alloys

Hardfacing is one of the adaptable methods that can build up the hard and wear resistant surface layer of different materials on the surface of substrate material. It helps them withstand wear, as well as prevent corrosion and high temperature oxidation. In the present investigation three different types of Fe–C–Cr based hardfacing electrodes with varying chemical compositions were deposited on ASTM A36 steel substrate by using manual metal arc welding (MMAW) process. ASTM A36 steel was selected as a base material after consulting with Pressure and Process Boilers, Saharanpur (India), which is a leading manufacturer of boilers. ASTM A36 steel is mostly used by this company for the production of induced draft fans. MMAW process with direct current constant current type power source was used to deposit the hardfaced layers of uniform quality. Straight polarity was used for MMAW process so that more of the arc heat should be concentrated on the electrode. The hardfaced samples were characterized using various characterization techniques and the results of the same were also outlined in the present investigation.

Colorimetric hydrogen gas sensor based on PdO/metal oxides hybrid nanoparticles

We have synthesized new colorimetric hydrogen-sensing materials, PdO/metal oxide hybrid nanoparticles, in which palladium oxide was loaded upon surface of substrate materials via an acid-base reaction between a H2PdCl4 solution and substrate materials, ZnO, MgO, TiO2, and SiO2 respectively at 25 °C. The colorimetric hydrogen gas sensing properties of all the samples, PdO/ZnO, PdO/MgO, PdO/TiO2 and PdO/SiO2, were characterized and compared in order to investigate how hydrogen gas sensitivity would be affected by surface property of substrate materials. It was confirmed that the amount of the loaded PdO, which was thought to be closely related with the colorimetric hydrogen sensitivity, was quite different according to the substrate materials and was increased with increasing of the basicity of substrate materials (ZnO > MgO > TiO2 > SiO2). Consequently, among the PdO/metal oxide hybrid nanoparticles, the largest amount of PdO was observed to be loaded on ZnO substrate nanoparticles due to its highest basicity. The best colorimetric hydrogen gas sensing properties (color difference, ΔE = 71.57) was observed in PdO/ZnO hybrid nanoparticles, showing the most prominent color change from brown to black, when the sample was exposed to hydrogen gas of 4 vol% balanced with nitrogen for 2 min.

Plasma Exposure Behavior of Yttrium Oxide Film Formed by Aerosol Deposition Method

Aerosol deposition (AD) method is technique for forming high density ceramic films on substrate material surface at room temperature. The yttrium oxide films formed by the AD method (AD-Y2O3 films) have been developed as plasma resistance coating used for the plasma etching equipment. In recent years, plasma eroded particles from chamber components of the etching devices are regarded as a serious issue that they reduce the semiconductor device yield rate. AD-Y2O3 films which have excellent plasma resistance can reduce the eroded particles in the plasma etching equipment and greatly have contributed to manufacturing high integrated semiconductor devices. In this paper, the plasma erosion behavior of AD-Y2O3 films were investigated compared with sintered Al2O3, sintered Y2O3 and thermal splayed Y2O3 in order to clarify the reason why AD Y2O3 films were superior as plasma resistance material. The plasma etching rates of AD-Y2O3 films were not significantly different from other samples. It was assumed that the etching rates were dependent on the chemical stability to fluorine plasma of material. On the other hand, the surface roughness difference before and after plasma exposure of AD-Y2O3 films were much smaller than other samples. It was assumed that the surface roughness difference is dependent on the crystalline size of material. The structure of AD-Y2O3 films, which had high density and nano-crystalline structure, were eroded homogeneously and smoothly. It suggests AD-Y2O3 films do not generate large eroded particles and are superior to reduce the eroded particles in the etching devices.

Deposition of a Silicon Carbide Reinforced Metal Matrix Composite (P25) Layer Using CO2 Laser

The objective of this research was to deposit a silicon carbide (SiC) reinforced layer of P25 (iron-based matrix material) on substrate material surface using CO2 laser. Two experiments using CO2 laser were carried out in this research. In the first experiment set, a gravity feed system was used with one powder feed containing different percentages of SiC particles and iron-based powder. In the second experiment set, preplaced powder was placed on substrate material surface. According to the experimental results, only few SiC particles were found in the clad matrix in the first experiment, and no SiC particles were found in the second experiment. A high microhardness value was noted in the SiC clad (above 1000 HV) in the first experiment compared to the second experiment with hardness values ranging from 200 HV to 700 HV. This was due to the high precipitation of carbide particles in the clad material during the first experiment. A comparison of the two different experiments signifies that the first one was the best because a more uniform layer with less porosity was produced.

Laser surface alloying of commercially pure titanium with boron and carbon

Laser surface alloying with boron and carbon was applied to produce the composite layers, reinforced by the hard ceramic phases (titanium borides and titanium carbides), on commercially pure titanium. The external cylindrical surface of substrate material was coated by paste containing boron, boron and graphite, or graphite. Then, the laser re-melting was carried out with using the continuous-wave CO2 laser. This enabled the formation of laser-borided, laser-borocarburized, and laser-carburized layers. The microstructure or the re-melted zone consisted of the hard ceramic phases (TiB+TiB2, TiB+TiB2+TiC, or TiC) located in the eutectic mixture of Tiα'-phase with borides, borides and carbides, or carbides, respectively. All the composite layers were characterized by the sufficient cohesion. The significant increase in microhardness and in wear resistance of all the laser-alloyed layers was observed in comparison with commercially pure titanium. The percentage of hard ceramic phases in more plastic eutectic mixture influenced the measured microhardness values. The dominant wear mechanism (abrasive or adhesive) depended on the method of laser alloying, and the type of test used. The wear tests for longer duration, without the change in the counter specimen, created the favourable conditions for adhesive wear, while during the shorter tests the abrasive wear dominated, as a rule.

THE INVESTIGATION OF WEAR BEHAVIOURS OF SiC(p) BASED COATINGS PRODUCED BY GTA WELDING PROCESS

In this study, the silicon carbide (SiC) powder has been coated by using of GTA process on the surface of a substrate material from 45Mn5 steel. The abrasive wear behaviours of samples which had different amounts of coating powders were determined by pin-on-disc test apparatus. The effects of the formed microstructures and the production parameters on abrasive wear properties of samples in coated zone were investigated. The highest wear resistance was observed at 41.3 kJ/cm energy input, 0.44 mmsn-1 production speed and 2.5 gr. powder quantity. Additionally, the highest micro hardness rate was measured as 1250 HV0.2. It has been observed that through the forming of hard metallographic phases; such as M7C3, M2C and FeSi2 phases, the hardness and the wear resistance of coated surfaces were increased.

HVOF coating and laser treatment: three-point bending tests

HVOF coating is one of the protective coatings of metallic materials. The mechanical locking is the mechanism for bonding the splats onto the substrate material surface. Thermal integration of coating to the base material through melting and re-solidification is short coming in HVOF thermal spraying process. In the present study, thermal integration of HVOF coating via laser melting is considered. Inconel 625 powders are sprayed onto mild steel samples. The mechanical properties of laser treated and untreated-coatings are examined through three-point bending tests. It is found that elastic limit of coating reduces after the laser treatment. The defect sites at coating–base material interface are the origin of the crack sites. Moreover, some locally distributed splats with high oxygen content are also act as crack initiation centers.

Adsorption of poly(vinyl formamide‐co‐vinyl amine) onto silica particle surfaces and stability of the formed hybrid materials

AbstractIn order to produce silica/polyelectrolyte hybrid materials the adsorption of the polyelectrolyte poly(vinyl formamide‐co‐vinyl amine), P(VFA‐co‐VAm) was investigated. The adsorption of the P(VFA‐co‐VAm) from an aqueous solution onto silica surface is strongly influenced by the pH value and ionic strength of the aqueous solution, as well as the concentration of polyelectrolyte.The adsorption of the positively charged P(VFA‐co‐VAm) molecules on the negatively charged silica particles offers a way to control the surface charge properties of the formed hybrid material. Changes in surface charges during the polyelectrolyte adsorption were studied by potentiometric titration and electrokinetic measurements.X‐ray photoelectron spectroscopy (XPS) was employed to obtain information about the amount of the adsorbed polyelectrolyte and its chemical structure.The stability of the adsorbed P(VFA‐co‐VAm) was investigated by extraction experiments and streaming potential measurements. It was shown, that polyelectrolyte layer is instable in an acidic environment. At a low pH value a high number of amino groups are protonated that increases the solubility of the polyelectrolyte chains. The solvatation process is able to overcompensate the attractive electrostatic forces fixing the polyelectrolyte molecules on the substrate material surface. Hence, the polyelectrolyte layer partially undergoes dissolving process.

Influence of substrate material on the initial thin film growth during ion deposition from a glow discharge

If the argon is replaced by e.g. CH 4 during rf-sputtering, a carbon film will be grown on the rf-excited electrode. Two major processes take place simultaneously at this electrode: physical sputtering of the electrode surface by ionized energetic methane fragments. Ionized energetic methane fragments stick to the electrode surface, thereby forming a carbon film. Depending on the sticking coefficients and sputtering yield values of the methane fragments onto the exposed substrate surface there will be a certain time interval before the substrate surface is completely covered by a carbon layer. The average carbon film thickness d( t) does not increase linearly with time at the initial stage of growth (i.e. before the carbon film completely covers the substrate—electrode surface). The reason for this effect is that during the initial film growth the substrate surface gradually changes from a 100% substrate material surface to a 100% carbon film surface. Since the sticking coefficients of the methane fragments onto these two materials may differ, a non-linear growth rate will occur. Experimental results are presented that verify that the initial carbon film growth rate depends on the substrate material. By considering the combination of sputter etching and deposition a model that describes the general behaviour of the initial growth has been developed. The growth rate reaches a steady state value at an average thickness d 0 of only 20–50 Å. Since this represents only 10–20 atomic layers, considerable fluctations in film thicknesses at different points may occur due to the statistical nature of the process. To get information about the expected fluctuations a simple Monte Carlo simulation of the process has been carried out. From this simulation we obtain a first order approximation about film roughness, atomic mixing and film formation at the substrate / carbon film interface. These results also confirm the growth mechanism responsible for different growth rates on different substrate surfaces.

Material‐Selective Chemical Etching in the System InGaAsP / InP

Selective chemical etching of substrates in the III–V system is described. A new etchant composed of hydrochloric and phosphoric acids is proposed, and a detailed description of application is provided. It is shown that illumination and the intentional introduction of defects on the surface of substrate material greatly facilitate its removal even from the slow etching (111)A face. Thus on LPE layers grown on (111)B‐oriented substrates, both the (111)Ga,In and (111)As,P faces of the epilayers can be exposed.