Alumina ceramic

Substrates most commonly used for thin-film heads are ceramic alumina TiC wafers. The production steps are as follows (see Figs 20.4 to 20.6 and Ref. 3) ... 

UOP Ketomax 100 S. olivochromogenes PEI-treated ceramic alumina with glutaraldehyde crosslinked, purified G.l.Rohrbach, 1981. 5.2... 

Iron(III) oxide or alumina is refined from bauxite. Approximately 175 million tons of bauxite are mined annually worldwide, with virtually all of this processed into alumina. Alumina is a white crystalline substance that resembles salt. Approximately 90% of all alumina is used for making aluminum, with the remainder used for abrasives and ceramics. Alumina is produced from bauxite using the Bayer process patented in 1887 by Austrian Karl Josef Bayer (1847-1904). The Bayer process begins by grinding the bauxite and mixing it with sodium hydroxide in a digester. The sodium hydroxide dissolves aluminum oxide components to produce aluminum hydroxide compounds. For gibbsite, the reaction is Al(OH)3 + NaOH —> Al(OH)4 + Na+. Insoluble impurities such as silicates, titanium oxides, and iron oxides are removed from the solution while sodium hydroxide is recovered and recycled. Reaction conditions are then... 

Ceramics Alumina. Catalyst, Molecular Sieves, Substrates. Insulator Body, Tilemix, Press Feed, Proppants, Frits, Colors... 

Fast Pyrolysis of Methane in Tubular Reactor. We have conducted a series of experiments on fast pyrolysis of methane using ceramic (alumina) and quartz tubular reactors. 

Figure 15.10. (a) Pore structure in a Shirazu Porous Glass (SPG) membrane, featuring highly tortuous pores, (b) Top-layer structure of a ceramic alumina membrane, made by sintering ceramic particles together. 

Van Vccn H.M., R.A. Tcipstra, JP.B.M. Tol and H J. Vcringa, 1989, Three-layer ceramic alumina membranes for high temperature gas separation applications, in Proc. Int Conf. Inorg. Membr., Montpellier, France. 

This novel route involves the retention of colloidal dispersions of zeolites (silicalite-1 described here) onto the surface of macroporous ceramic substrates. Silicalite-1 colloids were synthesised as described by Schoemann [14]. These were characterised by SEM and filtered through ceramic alumina discs. 

Cmtinuous Laminated Board. Laminated board with incombustible facing materials (glass fiber, ceramic, alumina-paper), or kraft paper is also widely used as a thermal-insulating building material. For example, laminated board is used for roof, ceiling, wall, and floor applications and for refrigeration storehouses. For producing continuous... 

If a thinner membrane is required, then one must choose a supported membrane. The permselective metal layer may be palladium or, more commonly, palladium-silver alloy, palladium-copper alloy, or other alloy of palladium. The permselective layer ranges in thickness from about 2-25 /an thinner than 2/rm is very difficult to achieve without introducing pin holes and other adverse defects into the permselective layer. The support layer is porous and is composed of either metal (such as sintered stainless steel or tightly woven wire cloth) or an inert ceramic alumina is very common. Since all of the mechanical strength is derived from the support layer, consideration must be given to its shape and thickness. 

A.F.M. Leenaars, Preparation, Structure and Separation Characteristics of Ceramic Alumina Membranes, Thesis Twente University, The Netherlands, 1984. 

FIGURE 16.7 Sandwich polyoxometalate (POM) catalyst recycling through nanofiltration based on a ceramic alumina membrane. 

Hydrophobic membranes attracted a thicker irreversible adsorption layer than hydrophilic membranes [127, 128]. Hydrophilic membranes display low sorptivity for fouling macrosolutes such as proteins. In some situations, ionically charged membranes are more fouling-resistant than electroneutral membranes. The apparent high fouling-resistance of ceramic (alumina) membranes is worthy of special note, although the explanation of this... 

In this chapter, we will attempt to trace briefly the long and sometimes anfractuous history of important bioceramics including coatings. Emphasis will be put on the bioinert ceramics alumina and zirconia, as well as on bioactive, that is osseo-conductive calcium phosphates. 

Ceramics Alumina Femoral balls, inserts of acetabular cups, artificial heart valves, dental roots, bone screws, endoscope Bioinert Heness and Ben-Nissan (2004)... 

Begand, S., Oberbach, T., and Gliem, W. (2006) Mechanical properties of hip joint heads made of the dispersion ceramic - alumina toughened zirconia. Key Eng. Mater., 309-311, 1257-1260, 1261-1264. 

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