Porcelain high-alumina

The use of high-alumina porcelain insulators may allow the T alkalinity limit to be raised to 600 ppm (mg/1) CaC03. 

Materials containing more than 10% offoreign substances represent a transition to high-alumina porcelain and are rarely manufactured. 

K-mass (high alumina) heat resistant porcelain 1700 ca. 1800 very good felrly good 10" 2.46 at 20°C l. 72 kcal./ m. hr. °C... 

Refractory alumina High alumina Electrical porcelain ... 

Mechanical properties Symbol Units Quartz porcelain, plastically formed Quartz porcelain, pressed Cristobalite porcelain Alumina porcelain Alumina porcelain, high- strength Lithium porcelain... 

Alumina is used in ceramic products in varying amounts. However, discussion is usually limited to high alumina, which refers to those bodies containing 80 percent or more aluminum oxide. Ceramics with less than 80 percent alumina but still predominantly alumina are classified as porcelain. The most common aluminas are those containing 85,90, 94, 96, 99, 99.8, and 99.9%. Strength and other properties improve as the alumina percentage increases, bnt so do cost and complexity of processing. The properties are dependent not only on the alnmina content, but also on microstructure and porosity. 

Among the many other ceramic applications in which wollastonite can be used are glazed porous ceramics of nearly every kind, dinnerware, ovenware, artware, structural clay products, terra cotta, sanitaryware, chemical stoneware, ceramic-bonded abrasives, refractories, high alumina bodies, spark plugs, electrical porcelains, frits and investment castings. 

Slow crack is also observed for systems free of alkali. Results similar to those found for silicate glasses at room temperature are also found for a variety of other ceramic materials, such as porcelains, glassy carbon, Portland cement, high-alumina ceramics, silicon nitride, lead zirconite, and barium titanate [12]. 

High-alumina porcelain and heavily etched to remove silicate-bonding phase (2300x). 

Lasdy, the importance of electroceramic substrates and insulators should not be overlooked. Here one strives to raise the breakdown strength by eliminating the interesting conduction mechanisms just described. Spark plugs, high voltage insulators, and electronic substrates and packages are made from ceramics like alumina, mullite [55964-99-3] and porcelain [1332-58-7]. 

Other applications of ceramics require clay, either raw or purified, sand, and feldspar. Brick, porcelain, and white wares are made from these raw materials the main expenditure in making these products is in firing the mixtures of powders to a dense solid. Ordinary brick made from fire-clay requires a small amount of energy even refractory brick for high temperatures and chemical durability, made partly from purified oxides such as alumina or chrome ore,... 

The Chemical Dictionary defines porcelain as "ceramic wear made largely of baked clay (kaolin) coated or glazed with a fusible substance." Kaolin is defined as "(china clay white bole argilla porcelain clay white clay). A whiteburning clay, which, due to its great purity, has a high fusion point and is the most refractory of all clays." It gives the composition as "mainly kaolinite (40% alumina, 55% silica) plus impurities and water."... 

The strength of electrotechnical porcelain enriched with alumina is about twice as high. 

By partial or complete replacement of quartz by alumina, alumina porcelain is obtained with a very high. strength. The processing of pastes is made more difficult by the abrasive action of alumina. 

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