Papers by Keyword: Thickness

Abstract: The paper presents methods of obtaining and studying new materials - thin metal films of the Ni/Al system. The technique and main parameters of the resistive method of thermal evaporation of the alloy using a vacuum universal station are briefly presented. Samples of thin films of various thicknesses were obtained. The thickness of the material was determined both using a scanning electron microscope and a developed eddy-current gage system operating under a hardware-software complex. In the course of the research, the limit the film thickness gauging capabilities of the developed gage system was established (400 nm). The ability of the gage system to detect differences in the thickness of the same film was shown using the developed method. Also, the possibility of determining the thickness of an undoubtedly unknown thin film by an eddy-current transducer signal amplitude has been demonstrated.

Abstract: Solid oxide fuel cell has become one of the interest in the sustainable energy field. In order to improve the efficiency of a solid oxide fuel cell (SOFC), the interconnect must be coated with a protective coating of (MnCO)₃O₄ spinel coated stainless steel. Commercial manganese cobalt (MnCO)₃O₄ was used as a protective coating on ferritic stainless steel in this study using the electrophoretic deposition (EPD) coating technique. This article examines the impact of voltage deposition towards morphological characteristics. The goals of these studies are to find the best interconnect coating parameter while experimenting with voltage deposition. The spinel coated interconnect (MnCO)₃O₄ was studied using Elemental Energy Dispersive X-ray Spectroscopy (EDS). The surface morphology and coating thickness are examined using a Scanning Electron Microscope (SEM). X-ray diffraction (XRD) is used to determine the phase of the spinel coated interconnect. The EPD coating technique for (MnCO)₃O₄ spinel coated interconnect is carried out in an aqueous suspension with 30V and 40V with coating durations of 20s, 30s, 40s, 50s, and 60s. By observing the deposition morphology and thickness coating at 30V and 40V, the best covering parameter for interconnect is 30V, 40s which fulfil the interconnect requirement.

Abstract: In this work we present a detailed analysis of the current-voltage variance from tris(8-hydroxyquinoline)aluminum (Alq₃) based organic light emitting diodes using general-purpose photovoltaic device model (GPVDM) software as a function of: the choice of C₆₀, the thickness of emission layer and hole-transport layer. The electrical and optical parameters of all layers were extracted from the material directory available in GPVDM. The calculations fully consider dispersion in glass substrate, indium tin oxide anode, the organic layers as well as the dispersion in the metal cathode. As expected, applied voltage was strongly dependent on the thickness of the function layer inside the devices. Finally, guidelines for designing devices with optimum turn-on voltage and thickness are presented.

Abstract: Magnesium Oxide (MgO) board has been widely used in prefabricated lightweight steelframe wall systems and as the floor board covering component. It is a non-insulating sheathingboard product which consists of sustainable materials with the characteristics of fire resistance,weather-ability, strength, resistance to mold and mildew. Although MgO board has recentlyworldwide used in façade construction but the research data related to the laboratory work such asthe bending strength is still limited. The previous studies on the bending strength of MgO board arebased on various standards such as ASTM, JC688 and British Standard subjected to the productscharacteristics and patterns. Therefore, the bending strength values obtained were inconsistent andnot convincing. Thus, this paper aims to examine the bending strength of MgO board with threedifference thicknesses (6mm, 9 mm and 12 mm) based on BS EN 310:1993 subjected to threepoints bending test. The failure modes during three points bending test was observed and theexperimental results obtained were compared with the theoretical values and others relevantstandards. A total of thirty six specimens with twelve specimens for each thickness in two groupdirections namely longitudinal (length) and transverse (width) direction were tested. The specimenswere prepared based on BS EN 326-1:1994 and BS EN 325:2012. The maximum flexure load of thespecimens was recorded and arithmetic mean bending strength for each thickness was presented.The experimental results showed the tested MgO board was not achieved minimum bendingstrength for load bearing used. It is recommended to be used in non-load bearing façade claddingconstruction.

Abstract: Anodizing is an electrochemical process to produced anodic coatings for improving magnesium (Mg) properties such as corrosion-resistant. In this study, anodizing of pure magnesium in 1 M NaOH electrolyte for 1800 s and at 21 °C and different constant current or voltage was investigated. The effect of voltage and current on morphology and thickness of the resulting anodic layers was evaluated by scanning electron microscopy (SEM) equipped with EDX analyser. The thickness of the produced layers was determined to utilize digital image analysis. The results showed that using lower current of 0.08 A non-compact anodic layer was produced. When a higher current of 0.2 and 0.5 A was used compact and thicker anodic layers were produced compare to lower current of 0.08 A. The anodic layer produced at a constant voltage of 20 V was rougher, thicker and contained microcracks compare to anodic layers formed at constant voltage of 12 V and at constant current (0.2 and 0.5 A).

Abstract: The powder compact was directly sintered by a pack boride process to prepare an Fe-based material having a boride layer. The effects of process parameters such as sintering temperature and sintering time on the microstructure and quality of the layer were studied. The thickness of the layer, surface hardness, phase composition and properties of friction and wear were also studied. The results show that the boride layer was mainly composed of Fe₂B, and its thickness is uniform and firmly bonded to the substrate. The thickness and hardness of the layer gradually increase with time and temperature. When the sintering temperature was higher than 1050°C, the more obvious holes and looseness would be appeared in the layer, which was not conducive to improve the properties of material. The thickness of the layer has the best value range with this method. Ensuring the thickness of the layer within a suitable range by controlling the sintering temperature, sintering time and other process parameters was beneficial to reduce the brittleness of the boride layer and improve the friction and wear properties of the material.

Abstract: It is shown that micro-arc oxidation (MAO), implemented according to traditional schemes in electrolytic baths with mechanical and pneumatic mixers, does not provide the formation of uniform ceramic coatings on the surfaces of holes, grooves and slots in the details from the alloys of the metals of valve group, and is characterized by a significant cost and relatively low safety. Fundamental possibility of MAO realization in the inner cavities of the special counter electrodes by passing solutions of electrolytes through them is installed. The calculated and experimental researches of MAO, applied to the processing of ball details from aluminum and titanium alloys, are conducted. The most rational design parameters of counter electrodes, as well as the rational parameters of the flow of electrolyte solutions in the clearances between the surfaces of details and counter electrodes are revealed. Innovative schemes for MAO of spherical details are developed. By measuring the thickness and hardness of the formed coatings it is proved that MAO, in the internal cavities of the counter electrodes, provides for the formation of more uniform ceramic coatings on the details from alloys of valve metals, in comparison with the traditional MAO in electrolytic baths with pneumatic and mechanical mixers.

Abstract: The work shows the influence of the content of silicon in the aluminum alloy and the regimes of micro-arc oxidation (MAO) on the structure and properties of the formed coatings. Treatment of samples from high-silicon aluminum alloys AK12pch (Si ~12 %) and M244 (Si ~25 %) was carried out in two modes, which have different installation capacity MAO. The thickness, micro-hardness, porosity of the formed MAO coatings was investigated. It is established that the increase in the proportion of silicon in the aluminum alloy leads to the formation of MAO coatings of significant thickness (~230 μm), with low micro-hardness (HV ~650) and high porosity (up to ~16 %). Increase 4 times the installation capacity of MAO causes the growth of the thickness of the coating, reduces the porosity of the coating on the alloy AK12pch and increases the porosity of the coating on the alloy M244.

Abstract: The results of computer simulation processing and determination of limiting degree of deformation by the Kolmogorov criterion are presented. The derivation of the dependence for the evaluation of the destruction of low-plastic materials at the edge is made at bend angle of 90⁰

Abstract: To explore the role of dislocation slip mode playing in the size effect of mechanical behavior of metallic materials, the tensile behavior of Cu-5at.%Mn and Cu-20at.%Mn alloys with thickness (t) spanning from 0.1 to 2.0 mm is investigated. The results reveal that the yield strength σ_YS of Cu-5at.%Mn alloy displays an independence of thickness, whereas the ultimate tensile strength σ_UTS and the uniform elongation δ show an obvious size effect. The σ_UTS and δ first slightly decrease as t is reduced from 2.0 to 0.5 mm, but evidently drop when t is below 0.5 mm. A similar size effect is also exhibited in Cu-20at.%Mn alloy; however, the variation trend of “the smaller the weaker” in size effect can be weakened by the planar slip of dislocations occurring during the deformation of this alloy.