Ceramic Finishing Research Articles

Material removal mechanism of non-resonant vibration-assisted magnetorheological finishing of silicon carbide ceramics

In this study, the material removal mechanism of non-resonant vibration-assisted magnetorheological finishing (NVMRF) of SiC ceramics was researched for improving their surface quality and finishing efficiency. A theoretical model of the polishing forces considering the vibration was proposed to explain the effects of the vibration on the polishing forces. A theoretical model of material removal rate (MRR) based on the Preston equation was proposed for quantitative analysis by considering the synergistic effects of the normal force and total shear force. Moreover, a theoretical model and the smoothed-particle hydrodynamics (SPH) simulation of a single diamond abrasive for material removal were proposed to explain the reasons for the increase in the MRR. Combined designed processing experiment, introducing the vibration can enhance the normal force and total shear force, which make improvement of the MRR, surface quality and subsurface damage (SSD). Moreover, both the enhanced normal force and total shear force contribute to the MRR, and the normal force contributes more to the MRR than the total shear force. Thus, understanding the material removal mechanism of proposed NVMRF plays indispensable role to extend its application into more wider areas.

Deliberate Surface Treatment of Zirconium Dioxide with Abrasive Brushing Tools

Brushing with bonded abrasives is a flexible finishing process used to reduce the roughness of technical surfaces. Although industrially widespread, especially for the finishing of metallic surfaces, insufficient knowledge of the motion, the material removal, and the wear behavior of the abrasive filaments complicates predictions of the work result. In particular, the reliable finishing of ceramics with bonded diamond grains proves difficult due to increased material removal rates, quickly leading to undesirable changes in the workpiece geometry. Based on technological investigations with abrasive brushing tools, this article provides insights into the surface finishing of zirconium dioxide with a focus on finding compromises between reduction in the surface roughness and alteration of the workpiece shape.

Hierarchical Ceramic Coating Reduces Adherence of Cells, Blood, Bacteria, and Tissue on Titanium Microsurgical Instruments.

Progress in the field of microsurgery allows more detailed reconstructions of the smallest tissue structures. The applied instruments are left with biological residues after coming into contact with body fluids or tissue, leading to compromised surgical precision. Designing of residue-free innovative instruments would reduce the necessity of subsidiary practices and would improve the surgical precision. We designed a ceramic coating (Lotus ceramic coating system 26-LCC-26) that exhibits self-cleaning surface properties on coated titanium specimens. A titanium surface was modified by blasting technology and electropolishing, followed by applying a high-performance ceramic and sol-gel finish layer. The physical surface characterization was performed by scanning electron microscopy and measuring the contact angle. The cell-repellent properties and cytotoxicity were investigated using live-dead staining, BrdU, and lactate dehydrogenase assay. Furthermore, bacterial and fluid-adhesion tests were performed. Finally, blood compatibility was analyzed according to DIN ISO 10993. The composite system LCC-26 increased the hydrophobic character of the titanium surface (the water contact angle of 74.9 degrees was compared with 62.7 degrees of the uncoated native titanium; p < 0.01) and led to the fluid and cell-repellent properties shown by the reduction in fibroblast adherence by ∼50.7% (p < 0.05), the reduction in Staphylococcus aureus pathogen colonization by 74.1% (p < 0.001), and the decrease in erythrocyte adherence by 62.9% (p < 0.01). Furthermore, the LCC-26 coated titanium microforceps dipped in human whole blood exhibited blood-repellent character (reduction in blood adherence by 46.1%; p < 0.05). Additionally, cyto- and hemocompatibility was guaranteed in direct and indirect tests. Titanium surface modification on surgical instruments exhibits cell, bacteria, and blood-repellent properties with a full guarantee of cyto- and hemocompatibility. Thus, innovatively coated instruments could contribute to increased precision during microsurgical interventions and optimized medical operation routines in the future.

Wear resistance and surface roughness of two types of monolithic glass ceramics: An in vitro study

Aim: The purpose of study was to evaluate wear and surface roughness of ZLS compared to lithium disilicate glass ceramic before and after simulated mastication. Materials and Methods: Thirty samples were divided according to material of construction into three groups (n = 10). Group (1): E Max-CAD, Group (2): Celtra duo ZLS, Group (3): Celtra press ZLS. The sectioned samples of E-max CAD blocks were polished and crystalized. The sectioned samples of Celtra Duo ZLS blocks were glazed and fired. The Ingots of celtra press were lab pressed, sectioned, glazed and power fired. The two-body wear testing was done using chewing simulator. Each ceramic sample was weighed and evaluated for surface roughness before and after wear simulation test using electronic analytical balance and the optical profilometry, respectively. Results: IPS E-max CAD revealed highest amount of weight loss with no statistically significant difference between groups. The change in weight for each group was non-significant . The roughness mean value for E-max CAD was significantly decreased and recorded the lowest roughness change. No significant difference in the roughness mean value between the two celtra materials. The roughness change for either Celtra Duo or Celtra Press groups was non-significantly increased. Conclusions: ZLS Celtra ceramics had insignificant less wear and significant higher surface roughness with enamel antagonist compared to E-max CAD. Although wear and roughness were affected by the surface finishing of glass ceramics, the construction method of ZLS restorative materials had no significant impact on both.

ИССЛЕДОВАНИЕ ПРИМЕНЕНИЯ СОВМЕЩЁННЫХ МЕТОДОВ ОБРАБОТКИ МЕДНЫХ И АЛЮМИНИЕВЫХ СПЛАВОВ

The work purpose: the investigation of obtaining by a surface the required properties and possibility degree to control shaping processes. It is well-known that a shaping process is affected by many factors particularly at complex methods of processing. The analysis of machining condition impact upon surface layer quality of parts allows defining optimum parameters of cutting and increasing parts operation characteristics. &#x0D; Investigation methods: theory, experimental researches, statistical processing of results, mathematical modeling, analysis. &#x0D; Research results: there are defined criteria of surface quality at complex methods of shaping, roles of factors included in processing, mathematical models are formed, recommendations are formulated. &#x0D; Novelty: it consists in the definition of regularities in pore covering at metal ceramic finish machining and definition of processing conditions impact upon pore covering, and also in the definition of efficient conditions of aluminum alloy finishing at the combined method of shaping. &#x0D; Conclusions: as the investigations carried out show the combined methods of impact upon a surface at parts shaping allow reducing also cutter wear, minimizing collateral processing factors connected with heat generation, with increased friction forces and surface layer deformation of a billet at its processing. The combination of machining with electro-chemical processing allows not only having an influence considerable upon surface quality increase, but decreasing technological residual stresses and also contributing to the restoration of mechanical and physical properties of metal surfaces after electro-erosion processing at the expense of surface micro-layer elimination with the acquired thermal changes of structures.

Daylight control and performance in office buildings using a novel ceramic louvre system

This study examined the design and daylight performance of a new louvre screen for office buildings. The screen was evaluated for three different material finishes: specular aluminium as a traditional material commonly used in louvres, and two types of ceramic finishes, with the intention to reduce the systems’ environmental impact. The new system was assessed taking an unshaded window, a window with a rod screen and a window with venetian blinds as references. Annual performance simulations for a full-scale room, using the lighting software Daysim, were conducted to assess the effect of the three material systems on indoor daylighting levels and distributions using both the traditional Daylight Factor and climate-based daylighting metrics (Daylight Autonomy DA and Useful Daylight Illuminance UDI). The results show that the proposed louvre system can provide satisfactory daylight levels and visual comfort within the room, while ceramics appear as a promising alternative material to be used in the production of advanced daylighting technologies.

Feature extraction using frequency spectrum and time domain analysis of vibration signals to monitoring advanced ceramic in grinding process

New alternatives for monitoring the ceramic grinding process have been studied. Monitoring vibration signals is one of the most successful methods because some characteristics that describe the behaviour and influence of the process on ground parts are only noticeable by studying such signals. This study aims to monitor the finishing of advanced ceramics during the surface grinding process via digital processing of the vibration signals. Experimental tests were performed using a surface tangential grinding machine with a diamond grinding wheel and alumina (Al 2 O 3 ) test specimens. The vibration signal was measured by an accelerometer and recorded by an oscilloscope at a 2 MHz sampling rate. The tests were conducted at different depths of cut for two workpiece speeds ( v w ) under mild and severe machining conditions. Confocal microscopy and surface roughness R a measurements were performed after grinding each workpiece to classify the samples. Digital signal processing was performed to achieve feature extraction. A frequency range of 800 Hz-2 kHz was most strongly related to the post-grinding ceramic condition. A correlation was found between vibration and integrity of the ceramic workpiece because the vibration signal was proportional to the surface roughness for each cutting depth used. To support the conclusion presented, a statistical analysis through variance by analysis of variance was performed.

NANO CERAMIC COATING APPLIED IN SURFACE TREATMENTS

This paper presents practical results of comparison of corrosion resistance in products with application of nano ceramic sealant, the results are compared with products that have surface treatments of electrolytic galvanization, KLT and organometallic. The ceramic nano sealant consists of nano metric colloidal silica. The tests carried out followed the procedures established in the international standard ASTM B117 which assigns test standards to evaluate the corrosion of products. To perform the tests, samples were developed with the application of the nano ceramic sealant and samples that only passed through the process of electroplating, KTL and organometallic electroplating. All samples were submitted to the tests established by ASTM B117. The obtained results, express superior performance of corrosion resistance of the products that went through the process with nano ceramic finish.

Effect of wear from cleaning operations on sintered ceramic surfaces: Correlation of surface properties data with touch perception and digital image processing

In the professional kitchen environment, frequent and harsh cleaning processes are one of the main causes of surface wearing. This experimental study evaluates the effects of abrasive wear on different ceramic surfaces, aiming at selecting the most reliable and durable material in terms of performances and aesthetics.Accelerated wear testing was applied on two ceramic finishes to simulate manual cleaning on commercial kitchen working tops.Roughness changes on aged ceramic samples were analysed by quantitative and qualitative techniques. Surface properties were investigated using non-contact profilometry, and then correlated with digital image processing. Paired-comparison test was used to explore users’ tactile responses to surface roughness modifications.Results showed that the aging process had a limited but significant effect on the sintered ceramic roughness change. Quantitative and qualitative analysis revealed that abrasive aging affected the two finishes in a different way, probably due to their different chemical composition. Paired-comparison test confirmed the findings based on the tactile user perception, and demonstrated to be a reliable qualitative tool for finishes selection, even when physical differences among the material samples are negligible.

Spatulas and abraded astragalus: Two types of tools used to process ceramics? Examples from the Romanian prehistory

Abstract In most of the Neolithic and Chalcolitic assemblages, north of the Danube, constantly appear two types of artifacts: spatulas made on longitudinal bipartitioned rib and abraded astragalus. Some specialists considered them tools used in different stages during the chaine operatoire of ceramics production. Starting from this functional hypothesis, we developed an experimental program in order to establish its reality. Thus, the first task included the processing of tools, using both the types of raw materials (rib of Bos taurus and astragalus of Ovis aries/Capra hircus ), and the technical transformation sequences identified in the case of archaeological artifacts. After the tools were processed, the spatulas were used in the action of modeling the ceramics' form, in order to eliminate the excess of raw material and to homogenize the surface. The astragalus, abraded prior to their utilization, were used for ceramic finishing, in order to mechanically polish the surface. In a third stage, the wear traces, developed on experimental samples, were compared with those present on archaeological pieces, illustrating a high degree of similarity. Our experimental program demonstrated the importance of experimental archaeology in the reconstruction the collective savoir-faire of Prehistoric communities.

A new prefabricated external thermal insulation composite board with ceramic finishing for buildings retrofitting

Given the high energy consumption connected to old buildings and their large environmental impact, there is a strong need for effective solutions for the building envelope retrofitting. Among these solutions, external thermal insulation composite systems (ETICS) have found large application in recent decades. In this paper a new kind of large-size thermal insulation composite boards, prefabricated using porcelain stoneware slab finishing, was developed. Different thermal insulating materials and adhesives, with and without glass fibre mesh, were tested by both current methodologies and purposely designed tests, in order to assess their physical–mechanical properties and durability performance, finally selecting the most suitable materials for the composite board. The strong points of this composite board are mainly: (i) its short placing time and improved execution quality, due to prefabrication; (ii) its high aesthetical value; (iii) its high durability, as the finishing layer is mostly insensible to weathering. The results highlight the good performances of the prefabricated composite board developed in this study (generally higher than current ETICS). The testing procedure followed in this study is also meant to give a contribution to the establishment of methodologies for the selection and durability assessment of materials for the building envelope retrofitting.

Modelling of Grain Motion for Three-body Abrasion

Surface formation for three-body abrasion is essentially more difficult to model than for two-body abrasion. In contrast to grains embedded in the polishing pad and therefore time-invariant tool geometry for two-body abrasion, here a variable tool geometry is prevailing as a result of the rolling abrasive grains. Nevertheless, three-body abrasion is an important abrasive process in the surface finishing of glass and ceramics and the modelling of the surface formation for mechanical abrasive machining with loose grains is required for a better process understanding and enhanced process design.The modelling of the surface formation for three-body abrasion is dealt with by splitting the integral removal volume under the polishing pad into the removal of single grains and distributing the total polishing force according to the interaction of individual grains with the workpiece material. This new methodical approach intends to determine the material removal in discrete time steps for every grain and further on the generated new surface topography. Data from polishing experiments like concentration and form of abrasives, polishing load, surface topography and integral removal are applied to set up this analytic-empiric model. Crucial elements of this model are the geometry of single grains, their rolling motion under load and the principle of material removal. In this paper the simulation of the rolling motion of single abrasive grains using a numerical time step model is introduced.

1010 Shape Adaptive Grinding (SAG) : a new Process for Finishing of Ceramics and High-performance Alloys

1010 Shape Adaptive Grinding (SAG) : a new Process for Finishing of Ceramics and High-performance Alloys

Preparation of Cool Wool Natural Energy Storage Material

Preparing of cool wool natural energy storage materials from wool fiber is a feasible and effective method. The structure characteristics of wool and the reason that wool has cool properties were introduced. The preparation principle, preparation methods and properties of cool wool fiber was studied. The preparation methods of cool wool mainly include scale stripping and surface coating. Scale stripping mainly consists of Chlorination, oxidation, biological enzyme treatment and plasma treatment. Surface coating mainly consists of resin finishing and ceramic finishing. Slenderizing and adding energy storage materials are also the effective methods. Wool as a new concept of natural energy storage material is recognized by people.

Effect of two different finishing systems on surface roughness of feldspathic and fluorapatite porcelains in ceramo-metal restorations: Comparative in vitro study.

Objective:The objective of present study was to qualitatively and quantitatively evaluate and compare the effect of two ceramic finishing systems and diamond polishing paste on surface texture of two ceramic materials.Methodology:The 40 test specimens were randomly divided into two main groups (Group I and Group II). Which were subsequently veneered with feldspathic porcelain and fluorapatite leucite porcelain systems respectively. The samples in Test group I and Test group II were subjected to different abrasion and finishing systems (Soft Lex and White silicon and grey rubber respectively). The surface roughness of all the four groups was assessed qualitatively using the scanning Electron Microscope and profilometer.Results:The surface roughness of Feldspathic and fluorapetite porcelain increased after abrasion and finishing as compared to auto-glazed porcelin. The surface roughness was more in grey rubber disc group (Gp Ib) as compared to the soft lex disc groups. After polishing with the diamond paste, there was reduction in the surface roughness of both the disc groups. The Mean Ra values of the Feldspathic porcelain at three intervals were 0.52 ± 0.06, 0.54 ± 0.06, 0.32 ± 0.06 and 0.50 ± 0.04, 1.25 ± 0.10, 0.45 ± 0.6 respectively for grey rubber disc and soft lex groups. The Mean Ra values of Fluorapetite porcelain at three intervals were 0.40 ± 0.06, 0.52 ± 0.06, 0.30 ± 0.03 and 0.41 ± 0.04, 1.17 ± 0.09, 0.39 ± 0.07 respectively for grey rubber disc and soft lex groups.Discussion and Conclusion:The surface roughness was less in the polished samples as compared to the auto-glazed porcelain. The findings were more reinforcing in the soft lex group as compared to the white/grey rubber disc group. Between the two porcelain systems, the Fluorapatite leucite porcelain specimens exhibited better surface smoothness than feldspathic porcelain.

KARAKTERISTIK TANAH LIAT DAN PENGARUHNYA TERHADAP KEBERHASILAN WARNA GLASIR

This eksperiment attempts to solve common problems faced in ceramic finish, finishing ceramic objects have differences to resolve other matters. Glaze is a type of glass coating that is applied to coat the ceramic objects, this is an interesting layer to be studied, because the success glaze applications in ceramics is influenced by many factors.Applications glaze on ceramic objects have a very high level of difficulty, the difficulty seen in glaze formulas, application techniques, firing temperature, shrinkage of dry matter and the successful achievement of color after glaze the combustion process. This research is to determine whether the clay character has an influence on the success rate of the color will appear. The problem solving method uses the experimental method, this method is considered more appropriate to determine the level of success of an experiment relating to material containing chemical elements. Clay used is a type of stoneware clay has five classes of characters, clay are as follows: 1. Pacitan soil, wet soil has a reddish color, 2. Singkawang soil, wet soil has a whitish colour, 3. Sukabumi is a brightly colored ground, wet floor is a beige, with 4. Sukabumi, the dark ground, wet soil has a dark brown color, 5. Bojonegoro soil, wet soil has a light brown color. color Glaze five characters shall be applied on the surface of clay are: 1. young Greens, 2. Pink, 3. Greenish blue, 4. Brown 5. Dark blue. Character clay is relatively large contribution to the emergence of color glaze in accordance with the wishes or the plan, especially when using a formula based on the glossy glaze. Glaze formula will tend to be stable when there is a combination of stain with a glaze oxide, stable formula can also be found on the matt glaze, because it glaze was close or not transparent. coloring oxides are very sensitive to the character of soil temperature change is cobalt and fe ,experiment that required in advance if the formula contains two types of oxide glaze. Burning with the reduction or oxidation also will give effect to the glaze colors will appear. Keyword: experiment, color glaze, characters clay.

Heat Diffusion in Klinker Facade: The Study Case of a Gio Ponti Building

The researchers focus on the IRT procedure of heat diffusion in ceramic finishing materials of contemporary architecture. The aim of the research is the development of a method for the thermal characterization of clinkers, a very common ceramic finishing material of buildings. The first experimental phase was performed in laboratory on clinkers of different shapes, thickness, colors, and glazing surface. The researchers determined two characteristic parameters related to thickness and thermal conductivity, by the interpolation of the heating curve in function of time with an analytical curve (resulted from a particular solution of Fourier’s equation). This curve allows to obtain a parameter characteristic of the material of the specimens under investigation. At present time, the researchers have been studying the correlation between this parameter and the damage level in the specimens; they will be testing the model on real-scale study cases in the second experimental phase.

KARAKTERISTIK TANAH LIAT DAN PENGARUHNYA TERHADAP KEBERHASILAN WARNA GLASIR

This eksperiment attempts to solve common problems faced in ceramic finish, finishingceramic objects have differences to resolve other matters. Glaze is a type of glass coating thatis applied to coat the ceramic objects, this is an interesting layer to be studied, because thesuccess glaze applications in ceramics is influenced by many factors. Applications glaze onceramic objects have a very high level of difficulty, the difficulty seen in glaze formulas,application techniques, firing temperature, shrinkage of dry matter and the successfulachievement of color after glaze the combustion process. This research is to determine whetherthe clay character has an influence on the success rate of the color will appear. The problemsolving method uses the experimental method, this method is considered more appropriate todetermine the level of success of an experiment relating to material containing chemicalelements.Clay used is a type of stoneware clay has five classes of characters, clay are as follows:1. Pacitan soil, wet soil has a reddish color, 2. Singkawang soil, wet soil has a whitish colour, 3.Sukabumi is a brightly colored ground, wet floor is a beige, with 4. Sukabumi, the dark ground,wet soil has a dark brown color, 5. Bojonegoro soil, wet soil has a light brown color. color Glazefive characters shall be applied on the surface of clay are: 1. young Greens, 2. Pink, 3. Greenishblue, 4. Brown 5. Dark blue.Character clay is relatively large contribution to the emergence of color glaze inaccordance with the wishes or the plan, especially when using a formula based on the glossyglaze. Glaze formula will tend to be stable when there is a combination of stain with a glazeoxide, stable formula can also be found on the matt glaze, because it glaze was close or nottransparent. coloring oxides are very sensitive to the character of soil temperature change iscobalt and fe ,experiment that required in advance if the formula contains two types of oxideglaze. Burning with the reduction or oxidation also will give effect to the glaze colors willappear.Keyword: experiment, color glaze, characters clay.

A Study of Ultrasonically Assisted Fly Cutting for High Precision Machining Hard Brittle Materials

This paper describes ultrasonically assisted fly cutting for finishing advanced ceramics for hot-press dies used to fabricate glass lenses. Fly cutting can perform shallow machining, which realizes ductile-mode cutting of hard, brittle materials. Ultrasonically assisted machining can increase the critical cutting depth (i.e., the maximum cutting depth for ductile-mode machining of a surface). The technique proposed in this paper combines both techniques and enables precise finishing of advanced ceramics at a high machining efficiency. Ultrasonic assisted fly cutting was found to reduce tool fracture and improve the finished surface quality compared with conventional fly cutting.

E12 大面積電子ビーム照射によるセラミックスの表面特性向上(OS-8 放電加工(2))

Ceramics have many characteristics in excellent mechanical, electrical and thermal properties. Therefore they have been applied in many fields. However, it is very difficult to machine them precisely by mechanical machining method because of their hardness and brittleness, and also surface polishing is not easy. In this report, the applicability of large-area EB irradiation to surface finishing and surface modification of ceramics is discussed. As a result, surface smoothing was difficult but the repellency and the releasability of resin from ceramics surface could be improved under proper EB conditions.