Papers by Keyword: Surface Microstructure

Abstract: The work investigated the nature and features of surface strengthening of steel products during friction thermomechanical processing (FTMP) of the surface. For this purpose, changes in the structure and properties occurring under the influence of FTMP in test samples were studied, and the influence of energy parameters during FTMP on the amount of surface strengthening of the samples was also evaluated. As a result of the research work, the factors affecting the preliminary thermal strengthening and additional strengthening of 65G steel samples using FTMP were identified, which allowed to increase the microhardness of the steel in the processing zone by more than 2 times. At the same time, the microhardness was increased thermally to the level of about 580 kgf/mm², which is equivalent to 5800 MPa, and after FTMP, the microhardness increased to 1300 kgf/mm², which corresponds to 13000 MPa. It is also shown that the strengthened "white" layer formed during FTMP and located along their entire processing length is continuous, which characterizes the homogeneity and uniformity of the strengthening of the surface of the samples. The load distribution at FTMP was determined using a dynamometer and the circumferential force of friction processing was calculated, which made it possible to establish dependencies that show the strengthening characteristics taking into account the thickness of the friction disc. Taking these data into account, recommendations are offered regarding the optimal thickness of the reinforcing disc.

Abstract: The water absorption on self-cured acrylic resin is higher than the heat cured acrylic resin. Incoming water positions itself between the polymer chains and affects the surface microstructure of self-cured acrylic resin. The absorption of liquids such as Arabica Gayo coffee may aggravate the surface structure of self-cured acrylic resins due to their acid content. This study aims to find out the microstructure of self-cured acrylic resin surface after immersed in Arabica Gayo coffee for 2 and 7 days. This study used 5 specimens of self-cured acrylic resin (Meliodent^TM) with size 10x10x1,5 mm³. Each specimen was immersed in aquades for 24 hours to reduce the residual monomer and then be given different immersion treatments. The immersion temperature used was 55°C. After immersion, surface microstructure observation was done using Scanning Electron Microscope (JEOL JSM 6510 LA). The images obtained were bubbles after being immersed in aquades for 2 days and more on day 7, micro porous after being immersed in Arabica Gayo coffee for 2 days and more on day 7 than untreated specimens. The conclusion of this study is micro porous formed more on the surface of self-cured acrylic resin along with the duration of self-cured acrylic resin immersion in Arabica Gayo coffee.

Abstract: The global development of carbon composite materials has been devoting constantly in still more companies and research institutions. Pre-saturated fabrics known as prepregs have a significant position in this field. The common problem of many worldwide authors is how to determine their tensile strength. The problem with tensile load is mainly due to the extremely high strength of fibers filaments and structural fragility of the thin width of formed profiles. Therefore, indirect methods are usually used. They are based on a determination of the resonant frequencies or on a conversion of values obtained e.g. with bending test. In our case, some experiments have been based on the idea of added a non-composite material into the final structure. The aim of this work was also to find an appropriate modification of a surface of the additional element with regard to a mutual interaction, surface microstructure and mechanical properties of the resulting composite part.

Abstract: Special-effect finishes are used in many applications to create new color impressions, pronouncing the design of a product and at the same time making the product appear alive. Total appearance conducting color and geometrical factors such as gloss, shape, etc. Gloss is an attribute of visual appearance that originates from the geometrical distribution of the light reflected by the surface. This paper presents new technologies that were developed to objectively describe total impression of appearance special effect finishes, coated composites and automotive paints after real live tests.

Abstract: Micro-grinding is an important processing method in micro-manufacturing field. A series of micro-grinding experiments were done with several kinds of commonly used metal materials in the paper, and the influence of different grinding factors on the surface quality of the work-piece was discussed. The surface roughness and surface microstructure of each material were analyzed in micro-grinding. The general developmental law of the surface roughness in micro-grinding was got with different grinding parameters. The surface roughness model proposed by is accurately confirmed according to the experimental results. It provides significant results for the quality of micro-grinding and intense research for the development of micro-grinding.

Abstract: The surface topography and properties of coating layer have an important influence on penetration and distribution of the print ink. In this research, the main objective was to investigate the effect of binder migration on the coating surface microstructure. The surface microstructure was explored in the method of numerical and visual analysis using mercury porosimetry measurement, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The findings indicated that the binder migration on the coating surface affected the pore size, depth and distribution of the coated paper surface. The little binder migration in the consolidation phase of coating color made a contribution to the forming of the coating layer, which made the coating surface more smother to printing performance.

Abstract: The structure of low-carbon steels after saturation by nitrogen and carbon in the mode of electrolytic-plasma nitriding and carbonitriding on the surface structure of austenitic stainless steel 12Cr18Ni10Ti has been studied. Optimum modes of electrolytic-plasma nitriding and carbonitriding are determined ensuring the maximum saturation of nitrogen and carbon, the microhardness of the surface. It is established, that after electrolyte-plasma processing microstructure of steel 12Cr18Ni10Ti has martensite structure. As a result of the research it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness.

Abstract: The structure of low-carbon steels after saturation by nitrogen and carbon in the mode of electrolytic-plasma nitriding and carbonitriding on the surface structure of austenitic stainless steel 12Cr18Ni10Ti has been studied. Optimum modes of electrolytic-plasma nitriding and carbonitriding are determined ensuring the maximum saturation of nitrogen and carbon, the microhardness of the surface. It is established, that after electrolyte-plasma processing microstructure of steel 12Cr18Ni10Ti has martensite structure. As a result of the research it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness.

Abstract: The surface topography and properties of coating layer have an important influence on penetration and distribution of the print ink. In this research, the main objective was to investigate the effect of binder on the coating surface topography and characteristics. The surface microstructure was explored in the method of numerical and visual analysis using mercury porosimetry measurment and atomic force microscopy (AFM). The findings indicated that the binder content on the coating surface affected the pore size, depth and distribution of the coated paper surface. The conclusions were drawn that more amount of binder on the coating surface could contribute to improve the coating surface topography and the formation of even pore size and distribution, which was good to the paper surface characteristics and resulted in low roughness, high paper gloss, low ink absorption and high paper surface efficiency.

Abstract: Currently, interest in nanotechnology concept for cement composites is steadily growing. Results of investigations of the concrete surface, reinforced with nanostructured mineral fibers by using atomic force microscopy (AFM) and dynamic ultra-micro hardness tester (DUMHT) of the specific areas of surface are presented. For comparison plain concrete and concrete with addition of single mineral fibers investigated as well. The analysis of the obtained data has shown that as a result of the directed microdisperse structurization provided by nanoinitiators on a surface of fibers, increase strength and deformation characteristics of a material. The main objective of this paper is to research the mechanisms of pattern formation surface of the concrete contained the High-modulus basalt microfiber (HMBMF) as a solid carrier for nanoparticles.