Glazed Porcelain Research Articles

Comparison of Methods for Determining the Water Absorption of Glazed Porcelain Stoneware Ceramic Tiles

This work evaluated the water absorption of glazed porcelain stoneware ceramic tiles using three different methods. Two methods were based on a procedure of boiling in water, specified by standards ISO 10545 and ASTM C373, and the third was the vacuum method proposed by the standard ISO 10545. The three products produced under the three different firing conditions were tested according to a 22 factorial design, with intervening factors of the boiling time and immersion time for the methods involving boiling, and of pressure and immersion time for the vacuum method. The maximum saturation of the plates was evaluated by helium gas pycnometry testing. The results showed that no sample saturation occurs in the boiling water absorption test performed according to the conditions established by standards ISO 10545 and ASTM C373. The values of open porosity, using the method of helium gas picnometry, showed absolute values of saturation higher than those presented by the water absorption measured according to the current standards. Thus, the results showed that the current methods for determining the water absorption of glazed porcelain stoneware ceramic tiles do not guarantee the complete saturation of the plates and, therefore, they are not able to correctly measure this property.

Synthesis, properties and uses of chromium-based pigments from the Manufacture de Sèvres

Abstract Chromium (Cr) is at the origin of a wide variety of coloration (green, pink and brown) in porcelain glazes from the French Manufacture de Sevres. This element was introduced for the first time at the factory in 1804, just a few years after its discovery by Louis-Nicolas Vauquelin. Pigments for glazes were developed at the laboratory of the factory, leading to a palette of 76 references. While the synthesis protocol and the nature of the precursors of these pigments are kept in laboratory notebooks, the products have never been fully studied. In this work, the pigments composed of Cr were characterized by X-ray diffraction (XRD), UV-visible spectroscopy and X-ray absorption near edge structure spectroscopy (XANES). The analyses reveal the presence of common crystalline phases, and open new perspectives for the synthesis of pigments containing chromium at the Manufacture de Sevres.

Optimizing of near infrared region reflectance of mix-waste tile aggregate as coating material for cool pavement with surface temperature measurement

The heat generated from dark color asphalt, which is low in surface reflectance mainly contributes to the environmental problem called as urban heat island. Low reflectance at high energy wavelength of sunlight, such as visible light and infrared region will cause the pavement to have high surface temperature, due to high energy absorption from solar radiation. This paper presents the optimization result of cool pavement coating material based on selected tiles aggregate to achieve high near infrared region (NIR) reflectance. Three types of waste tiles were used in this study which are Full Body Porcelain (FBP), Monoporosa (MP) and Porcelain Glaze (PG). All the tiles were prepared in the form of aggregates. A linear model was formed as a function of mix tiles fraction and the analysis of ANOVA suggest that the linear term used for this model is significant. Diagnostics of the model was evaluated using box-cox plot, normal plot of residuals and optimized to predict the mix of the different type of tiles to produce the highest surface NIR reflectance value. The first solution suggests that 100% of MP tile can provide NIR reflectance of 0.53, whereas the second solution suggest that the combination of 50% FBP and 50% of MP tile aggregates could give NIR reflectance value of about 0.51. Experimental work on measuring surface temperature found that optimized samples, M1 and M2 with high NIR reflectance could significantly reduce surface temperature of asphalt pavement at range of 4.1°C–9.6°C. In conclusion, the results of optimization is reliable and this method able to provide significant information on optimizing mix of tiles material as to achieve high NIR reflectance value for coating materials of cool-pavement.

Whiteness and Gloss Evaluation of Porcelain

The influence of the firing conditions on the color characteristics and surface gloss of glazed porcelain after firing in a tunnel furnace is shown for a concrete example. The whiteness of glazed porcelain is determined according to the values of two indices: whiteness WI and tint T w . It is shown that the whiteness index WI of porcelain is closely associated by an inverse relation with the yellowness b * CIE L * a * b * and the tinting T w with the coordinate –a * (green) right up to inadmissible values. The gloss corresponds to a shiny or highly shiny surface of porcelain glaze.

Quality of communication between dentists and dental laboratory technicians for fixed prosthodontics in Riyadh, Saudi Arabia.

The fabrication of a clinically acceptable dental prosthesis requires proper communication between the dentist and the dental technician. Prosthodontic educators have been concerned with this interaction and communication. Fixed prosthodontics laboratories revealed that the technicians are often dissatisfied with the information provided in work authorizations.ObjectiveTo evaluate the quality of communication between dentists and laboratory technicians via work authorizations for fixed prosthodontics in both governmental and private dental laboratories in Riyadh area from the technician’s perspective.MethodsA sample of 66 dental laboratories, including all government dental laboratories and a selected number of randomly chosen private dental laboratories from each district of Riyadh (40%), participated in the survey.A questionnaire was developed to include questions related to the following areas of work authorization: clarity and accuracy of instructions, patient information, type of prosthesis, choice of materials, design and shade of the prosthesis and type of porcelain glaze. The questionnaire was answered in a face-to-face interview by technicians who were qualified in fixed prosthetic work. Data were analyzed through parametric tests (T-test and one-way ANOVA) to identify significant values (P < 0.05).ResultsThis survey showed a lack of communication between dentists and dental laboratories regarding the following: marginal design, pontic design, staining diagram, type of porcelain and glaze needed for the prosthesis. Significant differences were observed between the government and private dental laboratories. There was a greater lack of communication between the dentists and government laboratory technicians in Riyadh.There was no statistically significant difference between private laboratories of different areas in Riyadh city (P < 0.05).ConclusionThe quality of communication between dentists and dental technicians in Riyadh can sometimes be inadequate, and governmental laboratories have a lower level of communication.

Characterization of the rare oil spot glazed bowl excavated from the Xiao kiln site of north China

Abstract “Oil spot”, which is a famous decorating technique of black glazed porcelain in the Song Dynasty, is a representative handicraft of Jian bowls found in the Jian Kiln in southern China. An oil spot black glaze bowl was found in the Xiao Kiln in Anhui Province in a field investigation, which is the first time that this pattern of porcelain was found in this area. Various techniques were performed on this bowl and on another black glaze porcelain piece from the same archaeological layer, including optical microscopy, scan electron microscopy, XRF, Raman spectromicroscopy and XRD. The results show that its main chemical composition is similar to the black glazed porcelain from the Xiao kiln, and the chemical characteristics of the glaze are high Fe 2 O 3 (5.14%) and CaO (7.26%) and low Al 2 O 3 (11.85%) and the RO content is 0.83which is indicative of a calcium glaze and is close to the components of oil spot porcelains from Shanxi in northern China. The ferric oxide crystalline on the glaze surface indicates the phase transformation of γ-Fe 2 O 3→ e-Fe 2 O 3→ α-Fe 2 O 3 in the crystallization layer on the glaze surface and the anorthite crystalline at the junction between the body and the glaze. The vessel could be produced at a relatively high temperature in a specific oxidizing environment.

Experimental evaluation of thermal performance of cool pavement material using waste tiles in tropical climate

Thermal performance are important parameter that represent the characteristic of cool pavement. The purpose of this paper is to present the findings on experimental result of thermal performance of the coating materials, which were developed from three types of waste tile aggregate, namely Full Body Porcelain (FBP), Monoporosa (MP) and Porcelain Glaze (PG). The samples were prepared based on the optimal design mix as proposed during optimization process based on surface temperature behavior of the samples. Experimental work was conducted in 24-h basis for continuously 14days at actual tropical weather climate. The results showed that sample M1 with 100% of FBP provided the best result in terms of thermal performance, also the material was able to obtain highest surface temperature reduction up to 6.4°C during peak period and solar reflectance of 0.49 at near infrared region. Statistical analysis shown that sample M4, 100% of PG tile aggregate, depicted a less desirable result due to its surface temperature reduction was not significant as compared with other investigated samples, which is only 4.32° during peak period. Overall result conclude that both material FBP and MP have a good potential to be used as cool pavement coating material based on its thermal and spectral performance. Thus, this study provides a useful information on the selection of tiles material that could be used as cool-pavement coatings, and contribute for a more potential measurement in mitigating urban heat island effects.

Interaction between Cr-bearing pigments and transparent glaze: A transmission electron microscopy study

Spinel ZnAl2O4 and corundum Al2O3 doped with chromium are used as pink pigments in porcelain glazes. However, alteration of the color can occur during firing, and the resulting glaze appears brown and green respectively, instead of the expected pink. To investigate the mechanism of color change, electron transparent sections were prepared by Focused Ion Beam (FIB) at the interface between pigment and glaze. Observations under a transmission electron microscope (TEM) reveal a common mechanism for both systems. Al migration from the pigment towards the silicate melt results in alteration of the grain of pigments, and formation of a Cr enriched phase, with the same crystalline structure than the initial pigment. Furthermore, the formation of anorthite is reported, due to the increase of the local concentration of Al in the melt. The different morphologies of altered grains of pigment encountered in the glaze are discussed base on the TEM observations.

Influence of zirconia surface treatments on resin cement bonding and phase transformation

It evaluated the effects of different zirconia surface treatments on the bond strength of a resin cement to Y-TZP (yttria-stabilized tetragonal zirconia) ceramics, as well as their phase-transformations. 75 blocks (5 mm × 5 mm × 4 mm) of Y-TZP were assigned into five groups (n = 15): (tribochemical silica coating - TBS) zirconia surface was abraded by silica coated alumina particles followed by silanization; (GLZ1) zirconia surface received the application of a thin layer of low-fusing porcelain glaze, followed by hydrofluoric acid (HF) etching for 1 min; (GLZ5) glaze application + HF etching by 5 min; (GLZ10) glaze application + HF etching by 10 min; (GLZ15) glaze application + HF etching by 15 min. After etching, all the specimens were washed, dried and silanized. Cylinders of composites (diameter: 3.25 mm; height: 3 mm) were cemented to the Y-TZP blocks using a resin cement. All the specimens were subjected to aging (10,000 thermal cycles and 90 days storage), tested under shear conditions, and finally analyzed by a stereomicroscope (failure analysis). In addition, we also performed topographical and phase transformation analyses of the treated zirconia surfaces. The TBS group presented the highest bond strength value (23.34 MPa). The glazed groups presented low bond values and high prevalences of pretest failures. X-ray diffraction analysis showed a phase transformation for the TBS group (13.14%); however, there was no clear phase change observed for the GLZ groups. From our results, we concluded that tribochemical silica coating is the main Y-TZP surface conditioning for resin bond improvements.

Adhesive Cementation Promotes Higher Fatigue Resistance to Zirconia Crowns.

The aim of this study was to investigate the influence of the cementation strategy on the fatigue resistance of zirconia crowns. The null hypothesis was that the cementation strategy would not affect the fatigue resistance of the crowns. Seventy-five simplified molar tooth crown preparations were machined in glass fiber-filled epoxy resin. Zirconia crowns were designed (thickness=0.7 mm), milled by computer-aided design/computer-aided manufacturing, and sintered, as recommended. Crowns were cemented onto the resin preparations using five cementation strategies (n=15): ZP, luting with zinc phosphate cement; PN, luting with Panavia F resin cement; AL, air particle abrasion with alumina particles (125 μm) as the crown inner surface pretreatment + Panavia F; CJ, tribochemical silica coating as crown inner surface pretreatment + Panavia F; and GL, application of a thin layer of porcelain glaze followed by etching with hydrofluoric acid and silanization as crown inner surface pretreatment + Panavia F. Resin cement was activated for 30 seconds for each surface. Specimens were tested until fracture in a stepwise stress fatigue test (10,000 cycles in each step, 600 to 1400 N, frequency of 1.4 Hz). The mode of failure was analyzed by stereomicroscopy and scanning electron microscopy. Data were analyzed by Kaplan-Meier and Mantel-Cox (log rank) tests and a pairwise comparison (p<0.05) and by Weibull analysis. The CJ group had the highest load mean value for failure (1200 N), followed by the PN (1026 N), AL (1026 N), and GL (1013 N) groups, while the ZP group had the lowest mean value (706 N). Adhesively cemented groups (CJ, AL, PN, and GL) needed a higher number of cycles for failure than the group ZP did. The groups' Weibull moduli (CJ=5.9; AL=4.4; GL=3.9; PN=3.7; ZP=2.1) were different, considering the number of cycles for failure data. The predominant mode of failure was a fracture that initiated in the cement/zirconia layer. Finite element analysis showed the different stress distribution for the two models. Adhesive cementation of zirconia crowns improves fatigue resistance.

Reusing sanitaryware waste products in glazed porcelain tile production

Reusing the waste products generated in ceramic manufacturing is an environmentally responsible and sustainable approach. This study aims to protect natural resources, minimise raw material costs and manage waste-generated pollution by reusing the vitrified sanitaryware waste (VSW) products from Canakkale Kalebodur Seramik San. A. S. Six sample formulations were prepared under industrial conditions and compared with a standard tile body. The results indicated that using VSW in place of feldspar results in an increased firing shrinkage and decreased bending strength, whereas using VSW in place of pegmatite results in an increased bending strength and reduced thermal expansion coefficients. The reduction in the thermal expansion coefficients is an important finding that aids in meeting the dimensional and deformation requirements of porcelain tiles and also results in a slight lightening of the tile colour. This study shows that the fired VSW products can be used in glazed porcelain tile production as a sustainable and technologically, economically and environmentally suitable approach.

Effect of polishing method on surface roughness and bacterial adhesion of zirconia-porcelain veneer

The purpose of this study was to evaluate the effect of various polishing methods on surface roughness of zirconia-porcelain veneer and to correlate the findings with early bacterial adhesion. The study specimens were glazed (control group), glazed after fine polishing (glazed group) and polished with Exa Cerapol (Cerapol group) or with Shofu porcelain adjustment kit (Shofu group) (n =20). Surface roughness was then measured using profilometer and scanning electron microscope (SEM). After artificial saliva coating, the specimens were incubated in Streptococcus mitis suspension for 4h at 37°C. Adherent bacteria were quantified from SEM images. Streptococcal viability was assessed by LIVE/DEAD staining kit and fluorescent microscope. There were significant differences in surface roughness according to polishing method and surface material. Relatively smoother surfaces were found in zirconia surfaces and glazed porcelain surfaces. There were also significant differences in bacterial adhesion according to polishing method and surface material. Cerapol group showed minimal bacterial adhesion with more dead cells when compared to other groups. A positive correlation between surface roughness and bacterial adhesion was found in glazed porcelain surface and a negative correlation in zirconia surface of Cerapol group, both with no statistical significance. Within the limitations of in vitro study, surface roughness and bacteria adhesion were significantly influenced by polishing method and surface material. Also, there was a positive correlation and negative correlation between surface roughness and bacterial adhesion in glazed porcelain surface and in zirconia surface of Cerapol group, respectively.

Development of anorthite based white porcelain glaze without ZrSiO4 content

The aim of this study was to develop new compositions of white glazes without the addition of ZrSiO4designed for sanitary products obtained in a 12-h firing cycles at a maximum temperature of 1230°C.Alternative glazes with a good opacity and a high degree of whiteness were obtained, composed primarily of raw materials available on the domestic market in Poland. The opaque effect was achieved due to crystallisation of anorthite, which was identified as a major crystalline phase in the system. The glazes were characterised by a high whiteness value L*, greater than 90 in the CIELAB colour space, and a gloss, measured with a 60° light incident angle on the glaze surface, above 50%.The microstructure and structure of the glazes were measured with the use of a Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). The colour and gloss of glazes were measured with the use of a spectrophotometer and a gloss metre at a 60° angle of incidence. The topography of glazes surfaces, as well as the roughness level (Ra), were measured with the use of a confocal microscope.

Use of Zr–Si–Cd–Se Pigments for Decorating Porcelain

The particularities of using inclusion pigments for decorating porcelain are examined. The compositions of underglaze pigments and colored porcelain glazes based on inclusion pigments are determined. The reasons for the appearance of defects are presented and methods of eliminating defects indicated.

Colour-generating mechanism of copper-red porcelain from Changsha Kiln (A.D. 7th–10th century), China

Changsha Kiln, located at Changsha in Hunan Province, south of China, is famous for exported and coloured porcelain during the Tang Dynasty (A.D. 7th-10th century) period. Although the opinion that copper-red porcelain originates from Changsha Kiln is widely accepted in academic circles, chemical characters of glaze and colour mechanism of its copper-red porcelain have not been fully investigated and studied. Therefore, a shard of opaque glaze porcelain with red pigments which excavated at Changsha Kiln (A.D. 7th-10th century) was analyzed by Energy dispersive X-ray fluorescence (EDXRF), Synchrotron X-ray absorption near-edge spectroscopy (XANES), micro X-ray diffraction (μ-XRD), microscopy and scanning electron microscopy (SEM) methods. Combining with XANES and μ-XRD results, it indicates that metal copper is the major colouring-generation element status of the red hue. On the other hand, for the first time the study demonstrates that glaze of the sample from Changsha kiln is a typical phase separated-crystalline glaze with large particles surrounding acicular crystals which lead the opaque appearances. Because the sample from Changsha Kiln is Chinese ancient early stage copper-red porcelain relic, it will help to understand the origin of copper-red porcelain in China and enrich the knowledge of Chinese ancient ceramic culture.

The Exploration of Sr Isotopic Analysis Applied to Chinese Glazes: Part Two

To continue the enquiry into strontium isotope compositions in southern Chinese glazes, this study determines the strontium isotope compositions of porcelain glazes of Dehua ‘Blanc De Chine’ porcelain and blue‐and‐white porcelain, and Tai Po blue‐and‐white porcelain. Mixing lines are displayed in the strontium isotope compositions of the Dehua glazes, suggesting that raw materials of different natures were used to make the two glazes. By referring to the historical resources, a high‐calcium plant ash and a mixture of limestone and high‐silica ash can be suggested as the fluxes used in the recipes for ‘Blanc De Chine’ glaze and blue‐and‐white glaze respectively. The strontium isotope compositions of Tai Po blue‐and‐white porcelain glazes separate into two groups, suggesting that different recipes were used to make the same glaze. The group A includes too few samples to allow an identification of the raw materials used, while the strontium isotope compositions of group B samples suggest that a high‐calcium plant ash was added as the flux.

Titania (TiO&lt;sub&gt;2&lt;/sub&gt;) as Antibacterial Material in Ceramic Tiles: Effect of Composition

Titania (TiO2) is one of a common and favorable material use in the manufacturing industry due to its uniqueness and functional performances to human and environment. The study was focused on the performance of glaze added TiO2 (anatase phase) in the application of porcelain tiles. Anatase powder in micro size was used (varies at 5 wt%, 10 wt % and 15 wt%) to observe their performance as antibacterial materials. The anatase powders were mix into the glaze composition and apply to the porcelain tile through dip coating. The viscosity of each composition was observed to study their effect. Characterization used to observe the properties of anatase mixed glazed porcelain tile were X-ray diffraction (XRD), Scanning electron microscopy (SEM) and antibacterial test. The results shown that higher composition of anatase powder, viscosity of the mixed glaze is higher and a rougher surface of glazed tiles was formed. XRD result shows that the higher the composition is more the intensity of TiO2 on the glaze coating surface, supported by SEM results. Antibacterial testing towards E.Coli was observed by counting the colonies of bacterial growth in 0 hr, 2 hrs, 4 hrs and 8hrs. The antibacterial properties increase when the composition of anatase increases.

Flexible Automation in Porcelain Edge Polishing Using Machine Vision

The first step in producing glazed porcelain dishes is molding of raw material granules. Then, the biscuit of the dishes is formed. This process is performed by press machines under high pressures. Dishes formed have usually burrs around the edges. To improve flexibility and increase product quality, robots are employed for dish polishing process for which the exact position of the dish is required. This paper deals with the problem in a real world manufacturing line. Machine vision technology and image processing techniques are employed, implemented and integrated with the current robotic system to detect the pose (position and orientation) of biscuits, hence guiding the robot arm to perform its polishing operation at correct and most efficient pose. The system and algorithms have been developed. The development has been done for two representative sample dishes of circular and rectangular shapes, both of which were developed and tested successfully.

Fatigue behavior of Y-TZP ceramic after surface treatments

ObjectivesThe aim of this study was to evaluate the effect of three surface treatments on the biaxial flexural strength before and after mechanical cycling, and fatigue limit of a Y-TZP ceramic. MethodsDisc-shaped specimens were produced and three surface conditions were tested: CT (as-sintered, untreated), GL (thin layer of porcelain glaze), and AA (air abrasion with 30µm silica particles). Profilometric and phase transformation analyses were performed. Disks were submitted to biaxial flexural strength (BFS) before and after mechanical cycling (100N, 2×106 cycles) and staircase approach (n=20). The flexural fatigue limits (FFLs) were obtained at 102, 103, 104 and 105 cycles. ResultsTetragonal to monoclinic transformation was only observed for AA group (9.46% of monoclinic phase). Glazed group presented the highest Ra values. Flexural strength was higher for AA group; CT and GL groups were similar. The reliability was similar between groups. The mechanical cycling at 100N did not affected flexural strength. FFLs were higher for AA group, and the three surface treatments presented decrease in strength according to the increase in number o cycles.

Effect of Zirconia Thickness on the Tensile Stress of Zirconia Based All-Ceramic Restorations

Introduction: The purpose of the presented study was to evaluate the effect of zirconia thickness on the tensile stress of zirconia based all-ceramic restorations. Methods: Twenty zirconia disks with 10mm diameter were prepared in two groups using CAD/CAM system. The thickness of zirconia was 0.5mm in first group and 0.3mm in second group. After sintering, 0.4mm glass ceramic porcelain was applied to each disk. Then, sintering and glazing of porcelain carried out. Instron testing machine with 1mm/min crosshead speed used to evaluate the failure load of the samples. Biaxial Flexural strength standard formula employed to calculate tensile stress of specimens. Statistical analysis performed using SPSS software. Results: Although data analysis showed more maximum tensile stress in 1 st group, no significant differences were found between two groups. Conclusion: Zirconia with 0.5mm and 0.3mm thicknesses cause similar tensile stress in all-ceramic restorations and thickness of these laminates could be reduced to 0.7mm.