Porcelain Bodies Research Articles

Study of Adaptability of the Compound of Sulfonate Acid Water Reducing Agent with Ceramic Slurry Blank

In this study, we investigate the effect of four types of water reducing agen on fluidity, suspensibility, thixotropy and the particle size of ceramic slurry and analyze the corresponding mechanism. Those water reducing agen include Lignin sulfonate water reducing agent, Sodium metasilicate, naphthalene sulfonate formaldehyde condensate, and the inorganic compound reducing agent. Experiment results shows that the relative molecular mass, the structure of water reducer, the content, and the moisture content of ceramic blank particle can play an important role in the adaptability of both water reducing agen and ceramic slurry. We make a mixed water reducer with lignin sulfonate, sodium metasilicate, and naphthalene sulfonate formaldehyde condensate by the corresponding appropriate mass ratio: 3:2:1. Then we add the mixed water reducing agen by the total dosage of 0.6% into the designed ceramic castable. We find that the performance of the slurry is considerably better improved by the mixed water reducing agen than by either a single one or by the currently commercial inorganic compound reducing agent, such as better improvements in liquidity, the slurry particle size, the mechanical strength of dry body, and the damage strength of porcelain body.

Influence of Surface Treatment on Strength Distribution of Vita VMK 68 Dental Porcelains

Weibull distribution function is the most commonly used statistical model for the investigation of mechanical properties of dental ceramics and design process with dental ceramics. However, it is still unclear whether the Weibull distribution function is the most appropriate function for fitting the strength data of dental ceramics with different surface treatments. In this paper, three-point bending test results of feldspathic body porcelain (Vita VMK 68) specimens with four different surface treatments are analysed. According to goodness-of-fit tests (Anderson-Darling test, Kolmogorov-Smirnov test, and Akaike information criterion), it is shown that the type of surface treatment has an important influence on deviation of strength distribution from perfect Weibull statistics. It is concluded that estimation of the most suitable statistical model for Vita VMK 68 is not only a material-dependent but also a process-dependent (machining of the specimens) procedure.

Provenance research by INAA on ancient Chinese white porcelain excavated from the Maojiawan site of Beijing

More than one million shards of ancient Chinese porcelain were excavated at the Maojiawan pit in Beijing in September 2005. Among these shards, four types of ancient Chinese white porcelain were identified. The ages and provenances of three of these types of porcelain were accurately determined by archaeologists based on typology. However, different archaeologists interpreted the other/fourth type differently. According to the colour of the porcelain body, it was easily identified as the product of the Jingdezhen kilns of the Ming dynasty (1368–1644 AD). However, based on the vessel shape, this fourth type of porcelain was also identified as the product of the Cizhou kilns of the Yuan dynasty (1271–1368 AD). In order to determine the provenance of this type of ancient Chinese white porcelain, 131 shards comprising the four types of white porcelain identified at the site were selected as experimental specimens and analysed by Instrumental Neutron Activation Analysis (INAA). After the processing of experimental data by principal component analysis and geochemical analysis, the results show that the provenance of this type of ancient Chinese white porcelain is the Jingdezhen, not the Cizhou kiln.

Matching Ability of Dental Shaded Zirconia Ceramics and Veneering Porcelain

The matching properties of ceramics and veneering porcelain play an important role for the overall color and mechanical properties of dental crowns. The Vita VM9 veneering porcelain was coated on the surfaces of two zirconia, three-point flexural strength, heat shock resistance and the overall color after veneered with porcelain were tested. The results showed that the interlayer cracks, radial cracks or porcelain body cracks were not appeared in all samples during thermal shock experiments at 60~220°C. Their flexural strength was all above 700MPa and the overall color covered the common color of VITA-3D Master shade guide. There is good thermal compatibility between the two dental shaded zirconia ceramics and Vita VM9 veneering porcelain. The mechanical properties are suitable for clinical posterior teeth area restorative, and the overall color is also suitable for the requirements on the color and brightness of clinical dental restoration.

납석으로 카올린을 대체한 도자기 소지의 뮬라이트 형성과 특성

Mullite formation in a porcelain body was promoted extensively by replacing kaolinite with pyrophyllite. Effects of mullite formation and vitrification by substitution of kaolinite with pyrophyllite on the mechanical and thermal properties were investigated. Addition of 45-55% pyrophyllite (pyrophyllite (45-55%)-feldspar (30%)-Gairome clay (20%)) could vitrify the sintered samples (water absorption : 0.05%, bulk density : 2.66g/cc) and improve the flexural strength (122㎫) when fired at 1280℃. Mullite formation was found to be decreased with increasing content of pyrophyllite. On the contrary, beyond 50% of pyrophyllite quartz and cristobalite phases was found to be increased. Thermal expansion coefficient of the samples decreased with increase of mullite phase. In triaxial system of pyrophyllite-feldspar-clay, the mullite formation of the samples with 50% pyrophyllite reaches about 78.7% and thermal expansion coefficient was found to be 5.4×10??/K.

Characterization of transparent glaze for single-crystalline anorthite porcelain

The objective of this work was to design a transparent glaze for matching single-crystalline anorthite porcelain. Excessive amounts of quartz were used in glaze to improve surface hardness. Technological properties including hardness and thermal shock resistance were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies were also carried out to analyze the microstructure. The phases found in glaze were aluminosilicate glass, quartz and cristobalite crystals. The Vickers hardness of the transparent glaze was about 2.48GPa, which was much higher than that of commercial soft glaze and was close to hard porcelain glaze due to forming dispersed crystal particles (quartz and cristobalite) in the glass matrix. Moreover, the thermal expansion coefficient of the glaze was slightly lower than that of porcelain body which was easy to produce compressive stress in glaze surface to increase the strength of porcelain. And no cracks were observed on glaze surface after heat exchange three times from 220°C to 25°C, presenting excellent thermal shock resistance.

Paul-Louis Cyfflé's (1724-1806) search for porcelain

Seven unglazed figurines from private collections, attributed to Cyffle’s Terre de Lorraine manufacture in Luneville (1766–1780), were subjected to porosity and scanning electron microscopic analyses to determine bulk element compositions and the composition and nature of their constituent phases. One figurine bears the mark CYFFLE A. LUNEVILLE, three the mark TERRE DE LORRAINE. The studied samples pertain to four compositional groupings: (1) Two porous (18–20 % water adsorption W.A.) bodies containing milled quartz-rich frit +anhydrite (former gypsum) +phyllosilicate +Ca-rich matrix; (2) A soft-paste (artificial) porcelain body (10 % W. A.), containing quartz +calcic plagioclase (An 88–95 ) + glassy matrix. The latter is inferred to derive from a former frit. A coronitic, amorphous (as revealed by electron backscattered diffraction analysis) reaction rim is visible around the quartzes. The K-rich and Na-poor composition of the frit is best explained as a mixture of potassium nitrate, alum, calcined gypsum, sand, and moderate amounts of salt and soda; (3) A porous (23 % W. A.), hybrid porcelain body with finely milled particles of quartz, mullite-bearing hard-paste porcelain, Na-Ca-siliceous glass and metakaolinite; (4) Three hard-paste porcelain bodies, some with relict quartz, andesine plagioclase (An 37–45 ), pseudomorphs of kaolinite and the liquidus phase mullite in a glassy matrix. Well fired figurines have no W. A. due to the pervasive former melt phase, underfired figurines 7 %. These wares can contain small amounts of lead (1.8 wt% PbO) and SO 3 (0.6 wt%), suggesting the use of lead frit and gypsum. The diversity of Cyffle’s production is now better recognized. His trial-and-error experiments made use of a remarkably wide range of paste mixtures, with porcelain bodies in the French (soft-paste) and the German (hard-paste) tradition.

Effect of the Chemical Composition on The Pyroplastic Deformation of Sanitaryware Porcelain Body

Pyroplastic deformation is the bending of a ceramic specimen caused by gravity during heat treatment. It can be defined as the loss of shape of product during its firing. Pyroplastic deformation is related to properties of liquid phases formed during firing. Therefore, the effect of the chemical composition on the pyroplastic deformation of sanitaryware porcelain was investigated in this study. Systematical compositional arrangements were made according to different combinations of (SiO2/Al2O3) and (Na2O/K2O) ratios by using Seger formula approach. Pyroplastic deformation behaviour of compositions within a controlled firing regime was investigated by using fleximeter. The bodies were also prepared in a special form by slip casting method at laboratory scale in order to determine the pyroplastic deformation of the samples. The experimental results showed that a definite combination at SiO2/Al2O3 ratio of 5 and Na2O/K2O ratio of 4 give the lowest pyroplastic deformation in the porcelain body formulations. The pyroplastic deformation value of this composition was determined as 25 mm which is 44% lower than that of the standard composition (45 mm).

Evaluation of pyroplastic deformation in sanitaryware porcelain bodies

In this study, the effect of composition on the pyroplastic deformation of a sanitaryware porcelain bodies was investigated. Systematic compositional arrangements were made to combine different amounts of SiO 2/Al 2O 3 and Na 2O/K 2O ratios. It was found that fleximeter analyses can be successfully utilised not only to measure the viscosity of a system but also to determine the pyroplastic deformation behaviour of the vitreous bodies. Al 2O 3 and SiO 2 sources affect the mullite formation in the body formulation in that mullite formation increases as the clay–kaolin fraction increases. The composition variation with different Na 2O/K 2O and SiO 2/Al 2O 3 ratios affects the viscosity of the system as the amount of formed mullite increases. The formation of mullite crystals increases the viscosity and diminishes the pyroplastic deformation. In the current study, the formation of about 28 wt% mullite phases with higher viscosity (∼10 8.34 P) values through the combination SiO 2/Al 2O 3:5 and Na 2O/K 2O:4 ratios was sufficient to reduce the pyroplastic deformation of sanitaryware porcelain bodies.

Microstructure Characteristics of the Black-Glazed Shreds Excavated from the Qingliangsi Kiln

The black-glazed shreds from Qingliangsi kiln were studied. The glaze and body micro- structures, compositions and crystal phases were observed and analyzed by field emission scanning electron, microscope multiple functions electron probe-energy spectrum instrument and field emission transmission electron microscope. The iron oxide crystal in oil spot was mainly the ε-Fe2O3 in the orientation of the zone axis [001], and also few content of ε-Fe2O3 in the orientation of the zone axis [412]. The brown oil spots on the glaze surface were aggregations of a great deal of iron oxide hematite crystals. Bodies of black-glazed shreds have high Al2O3(26.47 % ~ 30.48%) and low SiO2 (62.77% ~ 66.20%), which pertained to the typical recipe of north porcelain bodies. The glaze are attributed to calcium-alkali glaze, and according to the ratio of Al2O3:SiO2, it belongs to the crystallization glaze.

Failure Analysis of COS used in Distribution System

Abstract – Failure cases of COS and cause of these were investigated. The fractured porcelain body had a large part in distribution system of KEPCO recently. Quality of the material of porcelain and cement was examined and manufacturing processes were checked. There was no notable difference in microstructure of the porcelains compared with a sound one but the failures was concentrated on which sulfur based compound used to stick steel on the porcelain body instead of the cement. The mechanical strength of sulfur compound varies depending on melting temperature. The compound started to melt around 135℃ and fired with blue flame above 160℃ because it contains sulfur. The mechanical strength of the solidified compound is in inverse proportion to the melting temperature. To guarantee the characteristics of the compound the melting temperature should be controlled. Keywords : Cut-out switch, COS, Fault analysis, Fractured porcelain, Sulfur compound 1. Introduction The electric utility system is usually divided into three segments that are generation, transmission and distribution. The distribution system consists of a much wider variety of components, loads and interconnections than does other segments. A primary distribution feeder is connected with various equipments such as fuses, distribution transformers, reclosers and switches. The system is exposed to many interruption possibilities, the most important of which are those due to primary overhead or underground cable failure or transformer failure. The feeder utilize cut-out switch (COS) to restrict the interruption caused by failures of overhead transformer and secondary loads. Fig. 1 shows the COS that is composed of porcelain body, steel connectors and fuse cartridge. The fuse cartridge has fuse links its inside that consists of short fusible element section to sense the overcurrent. Attached to this there is a long conductor, commonly called a fuse leader or fuse link tail which connects to the rest of the fuse hardware. It begins to substitute the porcelain body with polymer but the great part of COS having porcelain body. Fuses are the most efficient and simple protection devices. COS is the typical expulsion fuse that the most basic and effective type of overcurrent device presently being used by the utility industry. That is also one of the most reliable devices that they can provide their function for over 20 years with essentially no maintenance. Its main function is current interruption. What they actually do is setup a high dielectric environment that prevents the arc from re-establishing when the fault current passes through a current zero.

Study on the chemical composition features of Longquan celadon excavated from the Chuzhou site of Huai'an City in Jiangsu Province by EDXRF

A mass of Longquan celadon shards were excavated from the Chuzhou site of Huai'an City in Jiangsu Province, China. These celadon shards were fired during the period of the Late Yuan Dynasty to the Tianshun era of the Ming Dynasty, as identified by archaeologists at Nanjing Museum. In order to research the chemical composition features of this ancient celadon porcelain, energy dispersive X-ray fluorescence (EDXRF) for non-destructive analysis was used to determine the chemical composition of the porcelain body and glaze in these shards. The results indicate that Ti and Fe in the body of Longquan celadon are characteristic elements which can distinguish porcelain produced during the Late Yuan Dynasty from those produced in the Ming Dynasties. The results of the principal component analysis (PCA) show that different body and glaze raw materials were used for the production of porcelain in different periods and the raw materials of the body and glaze are also different for various vessel shapes. The chemical compositions in the porcelain body of civilian ware are slightly different. The imperial and civilian Longquan celadon porcelains produced during the Hongwu era to the Tianshun era of the Ming Dynasty are distinguishable by the MnO, Fe2O3, Rb2O and SrO content in their porcelain glaze.

Development of Electrical Porcelain Glazes from Non-Essential Materials in Ghana Using RO/R<sub>2</sub>O, R<sub>2</sub>O<sub>3</sub>, RO<sub>2</sub> Classification

The use of non-essential materials in Ghana like granites, cocoa pod ash and shells as fluxes has been studied in the composition of a local brown glaze in the Na2O-K2O-CaO-Al2O3-SiO2 systems to support electrical porcelain glaze development which hitherto relied totally on imported glazes. Chemical analyses have been performed on the various materials and revealed the presence of the right quantities of aluminous-silicate minerals necessary for combinations in glaze development using the Segar classification. It was found that the range of 0.2 - 0.4 molecular weight of the granites, 0.1 - 0.3 for the cocoa pod ash and 0.4 - 0.8 for the shells forming the R2O/RO2 group and the ratio of 1:12 for the clay and the sand was sufficient to cause excellent melt at 1200OC when 5% - 8% of local manganese and 5% local iron oxide were added to the recipe. The molecular weights of the various oxides in the R2O group were calculated from the chemical analyses of the various materials to reflect the right quantities of the oxides. The results also indicate that holding the RO/R2O group within the above limits and varying the clay to sand ratio from1:8 - 1:12, other glaze melting surfaces from matt to gloss are achievable. Physical examination of the melted glaze on the electrical porcelain bodies showed consistent rich brown colour, well vitrified with no crazing, peeling or pin holes, at pottery temperatures of 1140 - 12000C.

Synthesis and characterization of hematite pigment obtained from a steel waste industry

Pigments that meet environmental and technology requirements are the focus of the research in the ceramic sector. This study focuses on the synthesis of ceramic pigment by encapsulation of hematite in crystalline and amorphous silica matrix. Iron oxide from a metal sheet rolling process was used as chromophore. A different content of hematite and silica was homogenized by conventional and high energy milling. The powders obtained after calcinations between 1050 and 1200 °C for 2 h were characterized by X-ray diffraction and SEM analysis. The pigments were applied to ceramic enamel and porcelain body. The effect of pigment was measured by comparing L* a* b* values of the heated samples. Results showed that the color developed is influenced by variables such as oxide content employed, conditions of milling and processing temperature. The results showed that the use of pigment developed does not interfere in microstructural characteristics of pigmented material. The best hue was obtained from samples with 15 wt% of chromophore, heated at 1200 °C in amorphous silica matrix.

Fluxing action of illite and microcline in a triaxial porcelain body

Comparative studies were made on two types of triaxial porcelain bodies; one used conventional potash feldspar ( ST0) and the other used illite ( IT0) as the fluxing agents. Scanning electron micrographs showed that densification and mullite formation in the IT0 body had already occurred at 1000 °C suggesting that there was enough liquid to assist densification and mullite crystal growth. In the ST0 body, mullite crystals started to emerge around 1100 °C, while potash feldspar completely melted around 1200 °C. Full vitrification of the ST0 body required the firing temperature of 1300 °C, which was around 50 °C higher than the IT0 body. The IT0 body showed superior strength to the ST0 body at all studied firing temperature ranges and thus was possibly due to (i) a better densification, (ii) a higher amount of interlocking mullite crystals and (iii) the smaller amounts of residual quartz.

Substitution effect of silica source by amorphous silica on translucency in ternary quartz-feldspar-kaolin system porcelain

Translucency and whiteness are valuable characters of porcelain among ceramic products. Highly translucent porcelain is precious and called “translucent porcelain”. Therefore, many efforts have been made on improvement of translucency of porcelain. Ternary system porcelain; quartz-feldspar-clay system, is one of most widely studied porcelains, and the substitution effect of the silica source by amorphous silica from quartz silica is investigated in this study. In this study, the starting composition is 30 mass % silica–40 mass % feldspar–30 mass % kaolin, and quartz silica is substituted by designated amount amorphous silica. The substitution by amorphous silica caused the decrease of maximum density of obtained porcelain. However, the total visible light transmission increased with the increase of amorphous silica substitution. The reason is thought that, the substitution by amorphous silica made highly fluid glass phase at lower temperature and it enhanced the combination of micro pores in the porcelain body. The disappearance of micro pores brings the high translucency of the obtained porcelain.

Evaluation of Interfacial Bonding Strength between Laser Textured Metal Coping and Porcelain

Porcelain fracture at the interface between metal and porcelain is one of the most common clinical failures. For the clinical longevity, metal-ceramic prostheses must have satisfactory bond strength of the metal structure to porcelain. In this in-vitro study, to evaluate the effect of mechanical texturing of cast metal alloy for the interfacial bonding strength, sandblasting with Al2O3 and laser surface texturing in two different metal alloys were compared. To fabricate cast specimens, Ni-Cr and Ni-Cr-Ti alloy were casted with 25 x 0.5 x 3mm bar. Before porcelain application, 5 specimens of cast Ni-Cr alloy and 5 specimens of cast Ni-Cr-Ti alloy were abraded at 3-4bar air pressure, using 50μm aluminium oxide particles for 10s at 10cm distance. Other each 5 specimens of cast Ni-Cr alloy and Ni-Cr-Ti alloy were treated with laser surface texturing. The laser work was done with femtosecond laser. After surface treatment, surface morphology was observed under optical photographs and FE-SEM. Surface roughness and wettability were examined. All specimens were followed by application of opaque and body porcelain layers by recommendation of manufacturer. For the three point bending test, porcelain was added to the metal specimens to the dimension of 8 x 3 x 1mm in the central portion of each metal specimen. The device, containing the metal-ceramic specimen, was placed on a universal testing machine and loaded at cross head speed of 1.50mm/min until fracture of the specimen occurred. The failure load was recorded in a computer using software provided by the manufacturer of the testing machine. After the bonding test, FE-SEM was used to examine the fracture site and interface between textured metal alloys and porcelain.

Temperature Prediction in the System K<sub>2</sub>O-CaO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-P<sub>2</sub>O<sub>5</sub>

The composition of bone porcelain body belongs to the system K2O-CaO-Al2O3-SiO2-P2O5. According to the principles of experimental design of regression analysis method, the corresponding sintering temperature of a series of different composition can be measured. Based on XRD analysis and sintering theory and multivariate nonlinear regression analysis relationship of sintering temperature and the components is established by introducing P2O5/CaO, SiO2/Al2O3 and RO/R2O as independent variables. The regression equation that studies the relation can be obtained by using Matlab 2008a’s regression statistics toolbox and Spss software, which can not only assure the quantitative relation between sintering temperature and the components of bone porcelain, but also forecast the sintering temperature of bone porcelain.

Efeito da modificação da composição química na sinterização e microestrutura de porcelanas de ossos bovinos

Bone china é um tipo especial de porcelana que foi primeiramente desenvolvida no Reino Unido e é caracterizada pela alta resistência mecânica, grande alvura e translucidez. É fabricada com uma mistura de matérias-primas composta por aproximadamente 50% de cinza de ossos bovinos calcinados (OBC) e 25% de fundentes, 25% de caulim ou argilas plásticas. A modificação das proporções e tipos das matérias-primas originais, ou seja, a substituição de Cornish stone por feldspato para a fabricação de bone china acarreta numa alteração das proporções óxidos fundentes/SiO2. Quando fabricada com Cornish stone, a composição é de 50:25:25 (OBC:caulim:Cornish stone). A fabricação de bone china nesta proporção com OBC:caulim:feldspato já apresenta uma maior fundência e uma temperatura de sinterização inferior, mas muito próxima, da composição original inglesa. A modificação para a composição 60:20:20 faz com que ocorra um aumento da relação fundentes/SiO2, que leva a uma facilitação da sinterização devido à redução da viscosidade do vidro formado durante o processo. Nesta composição o material sinteriza a 1200 ºC, que é cerca de 80 ºC abaixo da temperatura de queima da composição inglesa original, e apresenta uma microestrutura final muito homogênea e de baixa porosidade.

Reuse of ornamental rock-cutting waste in aluminous porcelain

Large amounts of solid wastes are discarded in the ornamental rocks industry. This work investigates the incorporation of ornamental rock-cutting waste as a raw material into an aluminous porcelain body, replacing natural feldspar material by up to 35 wt.%. Formulations containing rock-cutting waste were pressed and sintered at 1350 °C. The porcelain pieces were tested to determine their properties (linear shrinkage, water absorption, apparent density, mechanical strength, and electrical resistivity). Development of the microstructure was followed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The results showed that ornamental rock-cutting waste could be used in aluminous porcelains, in the range up to 10 wt.%, as a partial replacement for traditional flux material, resulting in a valid route for management of this abundant waste.