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Aluminum oxide ceramics

The poor efficiencies of coal-fired power plants in 1896 (2.6 percent on average compared with over forty percent one hundred years later) prompted W. W. Jacques to invent the high temperature (500°C to 600°C [900°F to 1100°F]) fuel cell, and then build a lOO-cell battery to produce electricity from coal combustion. The battery operated intermittently for six months, but with diminishing performance, the carbon dioxide generated and present in the air reacted with and consumed its molten potassium hydroxide electrolyte. In 1910, E. Bauer substituted molten salts (e.g., carbonates, silicates, and borates) and used molten silver as the oxygen electrode. Numerous molten salt batteiy systems have since evolved to handle peak loads in electric power plants, and for electric vehicle propulsion. Of particular note is the sodium and nickel chloride couple in a molten chloroalumi-nate salt electrolyte for electric vehicle propulsion. One special feature is the use of a semi-permeable aluminum oxide ceramic separator to prevent lithium ions from diffusing to the sodium electrode, but still allow the opposing flow of sodium ions. [Pg.235]

A sodium-sulfur cell is one of the more startling batteries (Fig. 12.23). It has liquid reactants (sodium and sulfur) and a solid electrolyte (a porous aluminum oxide ceramic) it must operate at a temperature of about 320°C and it is highly dangerous in case of breakage. Because sodium has a low density, these cells have a very high specific energy. Their most common application is to power electric... [Pg.640]

The heat transfer medium of the exchanger consisted of 1.6 mm (1/16") diameter, type A, 90% aluminum oxide ceramic beads (Coors Ceramic Co., Golden City, CO) with a specific gravity of 3.6 g/cm. Selected roasting conditions were maintained by control of bead temperature and resident time. The beads were heated to 240°C and were maintained in the chamber with the raw beans for 100 seconds in a 1 5 ratio of beans to beads. These processing conditions resulted in an exit temperature of the beans of 113°C. Roasted beans were cracked through a corrugated roller mill (Ferrell... [Pg.194]

The temperature increase in the single wells is clearly visible in the horizontal cross-section and in the vertical cut. The gas temperature in the wells also depends on the material of the titer-plate. In Figure 3.63, the gas temperature obtained in a steel titer-plate (heat conductivity 30 W mKT1) was compared with that in a titer-plate made of a less conductive material such as an aluminum oxide ceramic (heat conductivity 3 W mK-1). In either case, the gas temperature does not exceed the temperature of the solid material by more than 0.5 K and in the solid material between the wells this temperature drops towards the heater temperature. [Pg.467]

F. J. Gonzalez and J.W. Halloran, Reaction of Orthophosphoric Acid with Several Forms of Aluminum Oxide, Ceram. Bull, 59 [7] (1980) 727-731. [Pg.133]

The important properties of aluminum oxide ceramics are their high temperature stability (melting point of AI2O3 2050°C), their good thermal conductivity, their high electrical resistivity and their high chemical resistance. Their mediocre thermal shock resistance is a disadvantage. All these properties are dependent upon the chemical purity and particle size distribution of the oxide powder and the density, structure and pore size di.stribution of the ceramic. [Pg.460]

The various possible applications of aluminum oxide ceramics corresponding to specific properties are listed in Table 5.5-4. [Pg.461]

In contrast with pure aluminum oxide ceramics, the raw materials used in the manufacture of alumina-rich refractory products are, for economic reasons, natural products. The choice of aluminum silicates cyanite, andalusite or sillimanite (chemical composition Al203-Si02) or low iron bauxite with an AbOj-content > 85% and a Si02-content < 10%, depends upon the aluminum oxide content required. Natural mixtures of alumina hydrates (bauxite) and kaolin with Al203-contents of 48 to 70% are fired to so-called mullite chamottes. To obtain still higher AbO -contents, industrially produced corundum has to be added. [Pg.470]

Cannon, D.W. and Mann, R.V., Electrokinetic and surface charge characterization of a commercial aluminum oxide ceramic powder using the Matec ESA system, CMS Application Note 350, 1988, cited after [1027]. [Pg.960]

SiC-whisker-reinforced aluminum oxide ceramics have been developed especially for the... [Pg.331]

Ryu, R.K.N., Bovill, E.G. Jr, Skinner, H.B. et al. (1987) Soft tissue sarcomas associated with aluminum oxide ceramic total hip arthroplasty. A case report. Clin. Orthop. 216, 207-212. [Pg.542]

Figure 13. Transmission electron micrograph of a surface scratch resulting from the polishing of an aluminum oxide ceramic with diamond paste (grain size 6 pm). Figure 13. Transmission electron micrograph of a surface scratch resulting from the polishing of an aluminum oxide ceramic with diamond paste (grain size 6 pm).
Although diamond is the abrasive that is used most frequently for ceramics, other abrasives are also used. The basic rule is that their hardness must be greater than the hardness of the material being processed. It is generally best to process aluminum oxide ceramics with diamond abrasives. Silicon carbide wet abrasive papers can be used for graphite, zinc oxide, and silicate ceramics. [Pg.27]

Figure 60. Aluminum oxide ceramics, BF. (a) sharp-edged pull-outs after brief polishing with diamond of grain size 3 pm. (b) elimination of pull-outs by prolonged polishing with diamond of grain size 3 pm. Figure 60. Aluminum oxide ceramics, BF. (a) sharp-edged pull-outs after brief polishing with diamond of grain size 3 pm. (b) elimination of pull-outs by prolonged polishing with diamond of grain size 3 pm.
Figure 61. Aluminum oxide ceramic, BF. Porosity determined by buoyancy method 3.6% (a) After preparation at 250 rpm. Porosity determined by image analysis 5.4%. (b) After preparation at 750 rpm. Porosity determined by image analysis 3.7%. Figure 61. Aluminum oxide ceramic, BF. Porosity determined by buoyancy method 3.6% (a) After preparation at 250 rpm. Porosity determined by image analysis 5.4%. (b) After preparation at 750 rpm. Porosity determined by image analysis 3.7%.
Figure 62. Aluminum oxide ceramic with glass phase and pores, BF. (a) after final polishing, (b) after final polishing and coating with FeO. Figure 62. Aluminum oxide ceramic with glass phase and pores, BF. (a) after final polishing, (b) after final polishing and coating with FeO.
Figure 65. Aluminum oxide ceramic with 99.7% 0t-Al2O3, thermally etched, POL. Li t scattering effects in subsurface regions. All grain boundaries have been rendered visible, unlike the results of etching with phosphoric acid. Figure 65. Aluminum oxide ceramic with 99.7% 0t-Al2O3, thermally etched, POL. Li t scattering effects in subsurface regions. All grain boundaries have been rendered visible, unlike the results of etching with phosphoric acid.
Figure 66, Aluminum oxide ceramic with 99.7% a-Al203, coated with gold, BF. Light scattering effects from subsurface regions are suppressed by the thin film of gold. Figure 66, Aluminum oxide ceramic with 99.7% a-Al203, coated with gold, BF. Light scattering effects from subsurface regions are suppressed by the thin film of gold.
Figure 67. Aluminum oxide ceramic with 99.7 /o 01-AI2O3, thermally etched and coated with gold. Die. The grain boundaries have been made to stand out more clearly. Figure 67. Aluminum oxide ceramic with 99.7 /o 01-AI2O3, thermally etched and coated with gold. Die. The grain boundaries have been made to stand out more clearly.
Table 20. Recommended preparation procedure I for aluminum oxide ceramic a-A Os with SiO and MgO additives... Table 20. Recommended preparation procedure I for aluminum oxide ceramic a-A Os with SiO and MgO additives...
Aluminum oxide ceramic -Al203 with glass phase... [Pg.79]

Table 22. Recommended preparation of aluminum oxide ceramic a-Al203 with an abundant glass phase... Table 22. Recommended preparation of aluminum oxide ceramic a-Al203 with an abundant glass phase...
FIG. 3—Chart showing the effect of Impingement angle on erosion weight loss for metals and ceramics. Aluminum characteristics (typical for ductile metals) are shown In the dashed line. Aluminum oxide (ceramics) is represented by the solid line. The dashed line follows theory while the solid line deviation at about 40° represents practical experience (from Ref 1). [Pg.274]


See other pages where Aluminum oxide ceramics is mentioned: [Pg.404]    [Pg.404]    [Pg.460]    [Pg.460]    [Pg.460]    [Pg.677]    [Pg.543]    [Pg.1174]    [Pg.1179]    [Pg.43]    [Pg.53]    [Pg.72]    [Pg.72]    [Pg.72]    [Pg.74]    [Pg.75]    [Pg.76]    [Pg.380]    [Pg.383]   
See also in sourсe #XX -- [ Pg.460 ]

See also in sourсe #XX -- [ Pg.88 , Pg.91 , Pg.258 ]




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