Papers by Keyword: Surface Topography

Abstract: The average particle size of SiC used as raw materials is 60 μm, the filter membrane in a mass ratio of each component are: SiC : binder: sodium carboxymethyl cellulose (CMC): deionized water =9:1:1:20. Method of producing membrane by means of spin coating, the sintering temperature was set in different ranges. The Archimedes drainage method was used to measure its porosity, and the filter pressure of membrane was charactered by the filter pressure testing system, SEM was performed to characterize its surface morphology and microstructure. The results show that: when the temperature rises from 1225 °C to 1325 °C, the filter pressure of SiC porous ceramic filter membrane decrease firstly and then increase; the atlas trend of the porosity is roughly opposite with the filter pressure, the maximum of the porosity value is about 42% when the temperature reaches 1300°C, at this temperature, the filter pressure reaches a minimum value and the surface of the filtration membrane is the most flat. When the temperature reaches 1350 °C, the surface of the film started showing a plaque.

Abstract: This paper presents a study of 3D surface texture measurements and analysis of several surface texture parameters. A stylus measuring instrument was used to measure 3D surface topographies. In experimental part of this study, two coated gas turbine blades used in aerospace industry were chosen to examine surface of the coatings in nano-scale. Surface texture parameters of Ti-Al coating and Ti-Al-N coating were measured and compared to each other. The aim of the research is to analyze the surface of these coatings in an areal (3D) manner. The results indicate slight differences between these two surface textures despite the fact that both are Titanium-based coatings, and the surface of base material for both samples was prepared in the same way before deposition. Further study with repeated measurements of surface texture for deposed coatings has to be made after erosion tests.

Abstract: Many studies were carried out to investigate the ability of titanium alloys for dental implant. Surface treatment is one of the famous methods to increase the titanium surface properties. The purpose of this paper is to investigate the effects of acid etching on the surface topography and roughness of titanium alloys (Ti6Al4V ASTM 1472-99). Acid etchings were carried out by using different type of acids with same time exposures. All etched surface were characterized by using an X-ray diffraction (XRD), a scanning electron microscope (SEM) and a roughness tester. Acid etched and pure surface were comparatively analysed. Results obtained show that the type of acids influenced the surface topography as well as roughness properties. The microstructure of the surface is highly modified after acid etching. Further we can confirm that, the experimental etched titanium alloys had features of a roughened surface with micro-roughness. In general, the experimental surface (0.137 μm – 3.986 μm) was significantly rougher than control surface (0.124 μm).

Abstract: The contribution focuses to study of selected properties of thin coatings deposited on tool steel. Used samples were prepared by PVD method. Samples were evaluated using the scanning electron microscopy. Characteristics of surface morphology Ra, Rz Rt, RSm and RPc were established according to standard STN EN ISO 4287. The coatings TiN, TiCN, Supral and Exxtral Plus have been deposited on tool steel substrate having a thickness of 16 mm. The morphology characteristics were compared to the surface morphology of the reference material tool steel X155CrVMo12.1.

Abstract: In the measurement methods of microcosmic surface topography, laser interference microscopy with high precision and non-contact advantages, has been widely used. Based on the current processing algorithms of interference image, this paper studies principally the processing algorithms of single-wavelength laser interferometry and analyses the image processing algorithm of two-wavelength laser interferometry. On the basis of the original measurement precision, the two-wavelength measurement method can extend the depth measurement range and restore effectively the tested surface topography.

Abstract: The main goals of the improvements of manufacturing procedures are the increase of the material removal rate, the enhancement of the accuracy of the parts and the improvement of the surface quality. The specifications of the surface quality contain the requirements which ensure the proper functional conditions as well. An example among these is the twist-free surface on some special rotating shafts. In this paper we investigate the generated twist on surfaces machined by longitudinal and rotational turning and analyse the effects of the geometric parameters of rotational turning.

Abstract: In order to research and master the effect of surface topography on average film thickness between the end faces for mechanical seals, average film thickness fractal model between the end faces for mechanical seal was established using fractal parameters charactering surface topography characteristics, based on contact fractal model of the end face for mechanical seal, and solving micro-void volume. Effect of surface topography fractal parameters on average film thickness between the end faces for B104a-70 mechanical seal was analyzed by theoretical calculation. The results showed that fractal dimension D and characteristic length scale G of the end face had a great influence on the average film thickness h₀, and h₀ decreased with the increased of D or decreased of G; h₀ decreased rapidly with the increased of D or with the decreased of G when the end face was coarser, however, it decreased slowly with the increased of D or with the decreased of G when the end face was smoother. In normal working parameters and surface topography fractal parameters range, average film thickness between end faces was in the range of 0.27~1.7μm. Studying on the effect of the change of surface topography on average film thickness has an important significance on the predicting of operating characteristics of end faces during actual operating and the design of end faces for contact mechanical seal.

Abstract: In the paper analysis of surface topography influence on emissivity of metals was shown. This was performed for infrared band comprising wavelength region of 7.5 13 micrometers. Appropriate characterization and description of object emissivity has a crucial influence on accuracy of IR system for remote temperature measurement, e.g. IR thermography or pyrometry. These properties depend on many factors, including surface topography of material, where especially cavities play a very important role. In references so far emissivity are discussed mainly as influence of type of material (metal, dielectric), its temperature, wavelength or direction of emission. In the paper characterizing emissivity of construction materials in connection with 3D surface topography.

Abstract: Due to the induced effect of plastic deformation and markedly influence of contact friction, the surface topography of galvanized steels has changed along with time and space during the sheet metal forming. WykoNT1100 non-contact optical profilometer was used to measure the surface topographies of different deformation zones in Erichsen cupping test. And the surface topography models of different deformation zones were established based on the statistical method. The results indicated that the surface topography was roughened with the increase of deformation and the degrees of roughening in different deformation zones were different. The function curve of micro-peak height in punch fillet zone which had serious deformation was relatively flat. It indicated that the data distributions were scattered, the roughness values were large and the zinc coating was severely exfoliated. However, the function curve in vertex zone was lanky with centralized data, small roughness values and intact zinc coating. Moreover, the surface topography was also affected by the contact friction.

Abstract: Orthogonal experiments of micro mill-grinding were conducted on aluminium alloy 6061. Electroplated CBN compound tools were used in machining. Surface topography and roughness of the machined workpieces were measured and analyzed. Influence rules of radial cutting depth,feed rate and spindle speed on surface roughness in micro mill-grinding were studied. The results were compared with those in micro milling. It shows that the influence rules of processing parameters on surface roughness in micro mill-grinding are approximately same with those in micro milling. And in the same processing conditions, the surface roughness of micro mill-grinding is better than that of micro milling. The minimum value of surface roughness R_a of micro mill-grinding is 0.609μm in the experiments.