Types Of Porcelain Research Articles

Porcelain surface roughness, color and gloss changes after orthodontic bonding.

The purpose of this study was to evaluate the alteration in surface characteristics after orthodontic debonding of two types of porcelain systems commonly used in prosthetic dentistry. For this purpose, porcelain specimens were fabricated from low-fusing (n = 20) and high-fusing (n = 20) porcelain. The baseline surface roughness, color, and gloss were evaluated using profilometry, color shade index, and gloss study. All specimens were bonded with brackets and debonded using a testing machine at a rate of 0.1 mm/minute crosshead speed. The porcelain surfaces were polished using a 12-fluted carbide composite removal bur (low-fusing, n = 20; high-fusing, n = 20). In addition, half of each porcelain group was further polished using a series of Sof-Lex discs (low-fusing, n = 10; high-fusing, n = 10). The postdebond porcelain surface characteristics roughness, color, and gloss were reevaluated and compared with baseline measurements. The results were analyzed with two-way analysis of variance and Tukey multiple comparisons test, with porcelain type (low-fusing or high-fusing) and polishing protocol (carbide bur or carbide bur and discs) serving as discriminate variables at alpha = 0.05 level of significance. Bonding and debonding increased all roughness parameters tested; however, no change was revealed between the two polishing protocols. Similarly, gloss and color index changes were significantly altered after resin grinding, regardless of the polishing method used. No difference was identified between the two porcelain types with respect to roughness, color index, or gloss. Orthodontic bonding alters the porcelain surfaces, and postdebond polishing does not restore the surface to the prebond state.

The Difference between Traditional and Bone Porcelain Body

Porcelain is a traditional ceramic material, which is manufactured for centuries from a mixture of kaolin, quartz sand and feldspar. Another type of porcelain is produces on the basis on bone ash as fluxing agent. Traditional feldspar porcelain and bone porcelain bodies were compared depending on the firing temperature. Two mixtures of kaolin and potassium feldspar or bone ash were prepared. Bone ash is more intensive fluxing agent which need lower sintering temperature (1100 °C) in comparison with feldspar porcelain (1280 °C). Main difference between compared porcelain bodies is in mineralogical composition. Traditional porcelain based on mullite, quartz and glass phase, bone porcelain contains anorthite and β-tricalcium phosphate (β-TCP) and lower content of glassy phase.

Capodimonte porcelain: Glaze composition and its technological implications

This paper deals with the composition and the application technique of the glazes of the Capodimonte porcelain (1743–1760). The aim of the research was to complete the characterization of this type of historical porcelain, after the previous publication of data related to the body. The glazes were analyzed in thin section, in order to see the number of glaze layers, and by SEM/EDS for the determination of their chemical composition. All the glazes, both colored and uncolored, are of lead-alkaline type with a composition very similar to that of the glazes for the known production of majolica artifacts. They were fired at about 1000°C or less, so that their application was done by brushing when the porcelain body, previously fired at about 1200°C, was non porous. The chemical composition of the glazes permitted to define the raw materials used for obtaining them, and to calculate an approximate formulation of the batch. The raw materials are the same for all types of glaze, but their proportions can be significantly different, especially for lead oxide and sodium chloride.

Breakdown Process Experiments of 110- to 500-kV Insulator Strings Under Short Tail Lightning Impulse

Lightning is always a major cause of outages in power systems during these years, the description of insulator string breakdown process is a key part in lightning back flashover analysis. This paper builds a model to accurately depict the insulator breakdown process, which is applied to typical porcelain insulator or typical composite insulator under positive or negative impulse. The breakdown experiments of insulators of different string lengths for 500-, 220-, and 110-kV transmission lines are carried out under short-tail impulse. For comparison, the insulator breakdown experiments under standard lightning impulse are done as well. Then, utilizing the records of voltage, current data, and photos taken by high-speed cameras, the leader progression model is developed. Finally, the models are validated by being embedded in PSCAD software.

Meeting another China: exhibiting Chinese [folk] art and popular culture in the Orient Museum

This paper examines the role of Western museums, in particular the Museu do Oriente (Orient Museum) in Lisbon, Portugal, concerning the display of Chinese folk art and popular culture, contributing to a wider perspective of the image of China, after 500 years of artistic and cultural exchange between Portugal, Macau and China. The Orient Museum comprises a large collection of Chinese art and material culture which offers a wider perspective of Greater China. One aspect of the collection provides a ‘mirror’ of the cultural and artistic exchange between Portugal and China, while the other presents another perspective on China, focusing on the regional distinctiveness of Chinese ethnicity, religious traditions and the unique artistic practices of different regions of China. Unlike the typical porcelain, silk, furniture and other artworks that became familiar to Europeans as a result of global trade during the Modern period, the folk art and popular material culture from different regions presents another perspective on Chinese art and culture, traditionally considered within the scope of ethnography and therefore unworthy of display in encyclopaedic or art museums in the West. The main topics discussed in this paper include how Western communities perceive Chinese artistic, cultural and religious heterogeneity, how the museum acts as a place for intercultural dialogue through curatorial practices and parallel activities, the role of the museum in the conception of a non-stereotypical image of China, and the preservation of regional cultures as part of Greater China.

Archaeometric investigation of the relationship between ancient egg-white glazed porcelain (Luanbai) and bluish white glazed porcelain (Qingbai) from Hutian Kiln, Jingdezhen, China

Hutian Kiln, located in Jingdezhen City of Jiangxi Province of China, is well-known for the productions of bluish white glazed porcelain (Qingbai) from Song Dynasties (AD 960 – AD 1279) and egg-white glazed porcelain (Luanbai) of Yuan Dynasty (AD 1271 – AD 1368). Luanbai with an opaque glaze is thought to have evolved from Qingbai, which has a transparent glaze; however, the precise technological details for this process have not been adequately studied. This paper presents the analyses of samples of Luanbai and Qingbai porcelains from Hutian Kiln using various microscopic studies, including visible light spectrometry and Energy-dispersive X-ray fluorescence. Some distinct technical changes have been identified that help to explain the evolution from transparent Qingbai to opaque Luanbai glaze. First, there is an increase in the proportion of potassium-rich ingredients in sherds dating to Late Song Dynasty, which suggests a change in the glaze recipe. Second, during Yuan Dynasty, both types of porcelain share the same chemical composition, but Luanbai products display distinct micro-structures and opacity in contrast to the Qingbai ware. Third, the overall firing temperature of Luanbai is around 1270 °C which is generally around 100 °C higher than that of Qingbai. The opacity of Luanbai ware may be the result of different firing techniques, including the higher firing temperature and a correspondingly longer time to heat and to cool the glazed porcelain. The results reveal new insights on the coloring mechanism of the two kinds of glaze and the transition from Qingbai of Song Dynasty to Luanbai of Yuan Dynasty.

Flexural strength of dental porcelains with thermocycling and different firing protocols

Objectives: This is an in vitro study comparing the flexural strength of two dental porcelain after thermocycling, repetitive multiple firings and peak firing temperature (PFT) modifications. Materials and Methods: Two types of dental porcelains were used in this study: Cercon® Cream Love and Cercon® Cream Kiss (DeguDent, Hanau-Wolfgang/Germany). A total of 50 specimens per porcelain were divided into five groups with ten specimens per group. The first group was fired following the manufacturer's recommendations (control). The second group was fired 10 times repetitively, and the third group was fired and then exposed to 3000 episodes of thermocycling. The fourth group was fired with the PFT modified by + 10°C. The last group was fired with the PFT modified by −10°C. All specimens were tested for flexural strength with the three-point bending test using a universal testing machine (Instron) with a crosshead speed of 0.5 mm/min. Results: The flexural strength, mean (standard deviation [SD]) MPa, of Cercon® Ceram Kiss were: Control, 59.6 (7.82); 10 firings, 82.37 (26.32); thermocycling, 68.93 (9.55); PFT (+10°C), 75.28 (5.63); and PFT (−10°C), 75.94 (2.85). The results for the flexural strength, mean (SD), of Cercon® Ceram Love were: Control, 59.33 (9.9); 10 firings, 106.07 (28.43); thermocycling, 69.87 (11.17); PFT (+10°C), 65.7 (10.46); and PFT (−10°C), 51.1 (16.56). Conclusion: There was no difference in the flexural strength between the two veneering porcelains. In addition, repetitive firings significantly improved the flexural strength of both porcelains. Thermocycling significantly increased the flexural strength of both porcelains. There were no significant differences in the flexural strength when changing the PFT for Cercon® Ceram Love. Increasing and decreasing the PFT significantly increased the flexural strength of Cercon® Ceram Kiss.

Study on AC Flashover Performance for Different Types of Porcelain and Glass Insulators With Non-Uniform Pollution

The ratio <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> of top to bottom surface salt deposit density (SDD) affects the ac pollution flashover performance of disk insulator strings. The ac pollution flashover stress was established for fifteen different combinations of SDD and T/B in a systematic study, making use of seven-unit suspension strings with six different disk profiles in this paper. Then a comparison was made of pollution performance for glass and porcelain disks with the same profile. The observed relation of ac flashover stress <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">EL</i> to SDD and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> followed an equation of the form <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">EL</i> = <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> ·SDD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</i> ·(1- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</i> ·log( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> )) . The values of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> , <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</i> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</i> were fitted to test results for glass and porcelain disks of identical bottom-rib profile, and to four other bottom-rib and external-rib profiles. A reduction in the ratio <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> from 1/1 to 1/15 gave a median 26% ± 8% increase in flashover strength, corresponding to the calculated increase in overall pollution layer resistance. Extrapolation of results for the seven-unit strings to UHV dimensions suggests that some reduction in leakage distance can be accepted in areas where there is frequent natural washing of the top surfaces of disk insulators.

Influence of Surface Treatments on Adhesion of Porcelain to Titanium

This study evaluated the effect of etching solution surface treatments on the surface characteristics of titanium and adhesion of titanium/porcelain system by means of strain energy release rate (G-value, J/m²). Two hundred and forty five specimens of cp Ti plates were prepared. The specimens were divided into five groups in each test according to the surface treatment used; Gr MC (machined control), Gr AP (airborne particle abrasion), Gr E15, Gr E30, and Gr E60 (etching solution applied for 15, 30, and 60 minutes, respectively). The treated surfaces were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Three types of porcelains (Duceratin, Vita Titankeramik, Ti-22) were used to test adhesion with cp Ti. Following the four-point bending interfacial fracture test, the peeled fracture surfaces were examined using SEM. Data were analyzed using ANOVA and Tukey HSD test. Statistical significance was set at the 0.05 probability level. AFM and SEM analyses showed that the surface topography of cp Ti was modified after treatments. Bond strength values were significantly affected by surface treatment and by type of porcelain (p < 0.05). The cp Ti/Duceratin (E30 and E60 minutes) groups showed the highest G-value among the groups. Modes of failure were mixed and interfacial adhesive. Adhesion between cp Ti and porcelain could be enhanced by the use of experimental hot etching solution prior to porcelain firing as an alternative modality to the airborne-particle abrasion method.

Factors Affecting on the Bond Strength of Dental Zirconia to Veneering Porcelains

The bond strengths between two kinds of zirconia and three kinds of feldspathic veneering porcelains were measured. The specimens were prepared at four firing temperatures for three holding periods, respective opaque porcelain was painted and vacuum-fired. Then, each dentin porcelain was condensed in an acrylic resin mold and vacuum-fired under the conditions mentioned above. Cross sections of the interface between zirconia and porcelain were observed with a scanning electron microscope. The specimens were fixed to specimen holder on a universal testing machine. Data of the bonding test were statistically analyzed. The results showed that all the four factors statistically affected the bonding strength (p&lt;0.01). The contribution of the firing temperature was highest and that of the porcelain type was lowest (p&lt;0.01).

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.

Finite Element Analysis of Disc Insulator Type and Corona Ring Effect on Electric Field Distribution over 230-kV Insulator Strings

Insulator strings are widely used in power systems for the dual task of mechanically supporting and electrically isolating the live phase conductors from the support tower. However, the electric field and voltage distribution of insulator string is uneven which may easily lead to corona, insulators surface deterioration and even flashover. So the calculation of the electric field and voltage distribution along them is a very important factor in the operation time. Besides, despite the variety of insulator material and profiles, no remarkable endeavor regarding their impacts upon electric field distribution has been made so far. In this paper, three-dimensional Finite Element Method (3-D FEM) softwareMaxwell is employed to simulate several 230-kV insulator strings with various types of porcelain and glass disc insulators and the electric field along them were compared, to investigate the effect of insulator types on electric field distribution.

A comparative study of the fracture strength of dental porcelains: Vita VMK 95 versus Noritake

One fundamental dimension of long-lasting dental treatments which has attracted many researchers is the fracture strength of dental porcelains. To contribute to this aspect of research, we have compared the fracture strength of two types of porcelains in metal-ceramic restorations: Vita VMK 95 and Noritake. To carry out this research, a standard die made of stainless steel was prepared. Then molds were prepared from the metal and chalk die. In order to create metal foundations with equal thickness, Adapta Krupp sheets were used. After shaping the models with cheap metal, the frames were randomly divided into two groups of eleven. For one group Vita VMK 95 and for the other group Noritake porcelains were used for powdering. To measure the fracture strength of the samples, Hounsfield Test Equipment was utilized. Statistical analysis of the findings shows that Vita is significantly stronger than Noritake. Key words: Vita VMK 95, Noritake, Adapta sheet, porcelain, frame.

DC Flashover Performance of Various Types of Ice-Covered Insulator Strings under Low Air Pressure

In this study, icing flashover performance tests of typical DC porcelain, glass, and composite insulators are systematically carried out in a multifunction artificial climate chamber. The DC icing flashover voltages of seven typical insulators under various conditions of icing thickness, pollution severity before icing, string length, and atmospheric pressure are obtained. The relationships between icing thickness, salt deposit density as well as atmospheric pressure and the 50% icing flashover voltage are analyzed, and the formulas are obtained by regression method. In addition, the DC icing flashover voltage correction method of typical porcelain, glass, and composite insulator in the coexisting condition of high altitude, contamination, and icing is proposed.

Efeito da adição do resíduo de rocha ornamental nas propriedades e microestrutura de porcelana elétrica aluminosa

As porcelanas aluminosas são utilizadas como materiais de isoladores elétricos de alta tensão. Este tipo de porcelana se caracteriza por apresentar excelentes propriedades físicas, mecânicas e elétricas. As porcelanas aluminosas são fabricadas usando-se formulação de massa do tipo composta contendo caulim, argila plástica, feldspato e alumina. Na literatura é encontrada uma larga faixa de composições para essas porcelanas. Por outro lado, o setor de rochas ornamentais gera enormes quantidades de resíduos sólidos ricos em compostos fundentes, que podem ser usados como matéria-prima alternativa na fabricação de porcelanas. Neste trabalho foi estudada porcelana elétrica aluminosa incorporada com até 35 % em peso de resíduo de rocha ornamental em substituição do feldspato sódico, que é uma matéria-prima natural. As massas cerâmicas foram preparadas pelo processo via seca. Peças de porcelanas aluminosa em forma de disco foram preparadas por prensagem uniaxial a 50 MPa. As amostras foram sinterizadas em forno tubular a 1350 ºC por 1h. As seguintes propriedades tecnológicas foram avaliadas: retração linear, absorção de água, massa específica aparente, porosidade aparente, resistência à compressão e resistividade elétrica. A microestrutura sinterizada foi acompanhada por microscopia eletrônica de varredura e difração de raios X. Os resultados experimentais mostram que o resíduo de rocha ornamental pode substituir em até 10 % em peso o feldspato sódico na formulação de porcelana aluminosa. A microestrutura sinterizada foi fortemente influenciada pela adição do resíduo de rocha ornamental.

Cracking of Porcelain Surfaces Arising from Abrasive Grinding with a Dental Air Turbine

The purpose of this in vitro study was to evaluate porcelain cracking induced by abrasive grinding with a conventional dental air turbine and abrasive diamond burs. Four commercially available porcelains were examined-Wieland ALLUX, Wieland ZIROX, IPS e.max Ceram, and IPS Empress Esthetic Veneering porcelain. Sixty discs of each porcelain type were fabricated according to manufacturer instructions, followed by an auto-glaze cycle. Abrasive grinding using fine, extra-fine, and ultra-fine diamond burs was carried out, using a conventional dental air turbine. The grinding parameters were standardized with regard to the magnitude of the force applied, rotational speed of the diamond bur, and flow rate of the water coolant. A testing apparatus was used to control the magnitude of force applied during the grinding procedure. The ground surfaces were then examined under scanning electron microscope. Cracking was seen for all porcelain types when ground with the fine bur. Cracking was not seen for specimens ground with the extra-fine or the ultra-fine bur. Wet abrasive grinding with a conventional dental air turbine and fine grit diamond burs has the potential to cause cracking in the four porcelain types tested. Similar abrasive grinding with smaller grit size particles does not cause similar observable cracking.

Microstructure of Interface between Zirconia and Veneer Porcelain

To study whether the veneering technique will have an impact on zirconia grain and the bonding type and relationship on interface between zirconia and veneer porcelain. Materials and methods: After sintered, zirconia was annealed for 15 minute to finish the phase transition from m to t.4 types of veneer porcelains were sintered and observed with SEM (scanning electron microscopy) and TEM (transmission electron microscopy). Results: With etching time extending, it appeared that many materials loosed and corrosional pit deepened, enlarged in the veneer porcelain, which made crystallize structure move into veneering surface. Composition of interface mainly was amorphous glass matrix and zirconia. Energy spectrum analysis showed that there was no remnant glass composition in the zirconia side departing from interface. SEM showed that crystal in veneering side did not participate interface bonding. Conclusion: The interface between 4 types of veneer porcelains and zirconia bonded well. Veneering sintering technique didn’t change lattice structure of zirconia, which still was tetragonal structure. The specific bonding property of interface still remained to be analyzed further to determine.

The Design and Simulation Analysis to the Cap and Pin Type Porcelain Insulators’ Automatic Glue-Fitting Machine

It has designed a set of equipment which could automatically assemble porcelain insulator. And taking UG NX software as a tool, it has done a motion simulation to the whole perfect binding process, at the same time, it also has done advanced simulations and optimum designs to some important parts. Finally, this equipment could overcome the vibrator’s negative impact, and the coaxial tolerance between steel foot, porcelain and iron cap can be guaranteed less thanΦ1.4mm while the porosity adhesives can be guaranteed no more than 3%, and the fitting efficiency could up to 60 pieces an hour.

Flexural strength of fluorapatite-leucite and fuorapatite porcelains exposed to erosive agents in cyclic immersion

ObjectiveThe aim of this study was to evaluate the flexural strength of two porcelain materials (IPS d.SIGN and IPS e.max Ceram) exposed to erosive agentsMaterial and MethodsOne hundred and twenty bar-shaped specimens were made from each of fluorapatite-leucite porcelain (IPS d.SIGN) and fluorapatite porcelain (IPS e.max Ceram) and divided into 8 groups of 15 specimens each. Six groups were alternately immersed in the following storage agents for 30 min: deionized water (control), citrate buffer solution, pineapple juice, green mango juice, cola soft drink and 4% acetic acid. Then, they were immersed for 5 min in deionized water at 37°C. Seven cycles were completed, totalizing 245 min. A 7th group was continuously immersed in 4% acetic acid at 80°C for 16 h. The final, 8th, group was stored dry at 37°C for 245 min. Three-point bending tests were performed in a universal testing machine. The data were analyzed statistically by 2-way ANOVA, Tukey’s HSD test and t-test at significance level of 0.05.ResultsThe flexural strengths of all groups of each porcelain after exposure to erosive agents in cyclic immersion did not differ significantly (p>0.05). For both types of porcelain, dry storage at 37°C yielded the highest flexural strength, though without significant difference from the other groups (p>0.05). The flexural strengths of all groups of fluorapatite porcelains were significantly higher (p<0.05) than those of the fluorapatite-leucite porcelains.ConclusionsThis study demonstrated that the erosive agents evaluated did not affect the flexural strength of the tested dental porcelains.

Study on DC Pollution Flashover Performance of Various Types of Long String Insulators Under Low Atmospheric Pressure Conditions

In this paper, the dc pollution flashover performance of various types of porcelain, glass, and composite insulators is investigated. It also presents analysis of the dc flashover process of polluted insulator string at high altitude using insight from high-speed photography. The research results indicate that the relationship between the dc pollution flashover voltage and the string length of insulators is basically linear, the characteristic exponents describing the influence degree of air pressure on pollution flashover voltage vary between 0.35 and 0.77 and are related to the insulator types and pollution degree, etc., the characteristic exponents describing the influence degree of pollution on flashover voltage vary between 0.24 and 0.36 and are related to the insulator types and air pressure, etc. Based on the flashover phenomena using the insight from high-speed photography, a new physical model explaining the flashover mechanism for a polluted insulator string at high altitude is introduced, which can be expressed as an electrical circuit consisting of a surface arc of length x <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and air-gap arc of length x <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in series with a resistance representing the wet pollution layer. In addition, the exponent n describing the influence degree of air pressure on flashover voltage for the polluted insulator is discussed.