Preparation powders

C14H30CI2N2O4. White powder prepared from dimethylaminoethanol and succinyl chloride, followed by methylation. Neuromuscular blocking agent used to relax skeletal muscles during certain types of surgical operation. 

Johnson D W Jr 1981 Nonoonventional powder preparation teohniques Am. Ceram. See. Bull. 60 221-4, 243... 

Johnson D W Jr 1987 Innovations in oeramio powder preparation Ceramic Powder Science, Advances in Ceramics vol 21, ed G L Messing ef a/(Westerville, OFI The Amerioan Ceramio Sooiety) pp 3-19... 

Ganguli D and Chatteqee M 1997 Ceramic Powder Preparation Handbook NorweW, MA Kluwer)... 

Copper oxide powder, prepared by grinding copper oxide (wire form), is heated to dull redness in a porcelain basin, allowed to cool partially in the air and finally in a desiccator. 

Fig. 3.28 The Kiselev method for calculation of specific surface from the Type IV isotherm of a compact of alumina powder prepared at 64 ton in". (a) Plot of log, (p7p) against n (showing the upper (n,) and lower (n,) limits of the hysteresis loop) for (i) the desorption branch, and (ii) the adsorption branch of the loop. Values of. 4(des) and /4(ads) are obtained from the area under curves (i) or (ii) respectively, between the limits II, and n,. (6) The relevant part of the isotherm.

Fabrication technologies for ah electronic ceramic materials have the same basic process steps, regardless of the appHcation powder preparation, powder processing, green forming, and densiftcation. 

Powder Preparation. The goal in powder preparation is to achieve a ceramic powder which yields a product satisfying specified performance standards. Examples of the most important powder preparation methods for electronic ceramics include mixing/calcination, coprecipitation from solvents, hydrothermal processing, and metal organic decomposition. The trend in powder synthesis is toward powders having particle sizes less than 1 p.m and Httie or no hard agglomerates for enhanced reactivity and uniformity. Examples of the four basic methods are presented in Table 2 for the preparation of BaTiO powder. Reviews of these synthesis techniques can be found in the Hterature (2,5). 

Production of both monobasic aluminum diformate, (HO)Al(OOCH)2, and monobasic aluminum formoacetate, (HO)Al(OOCH) (OOCCH ), has declined. One reason could be the ready substitution of inexpensive aluminum formate solution (17—19) for soHd aluminum acetate in formoacetate in most of the common commercial appHcations. Monobasic aluminum formoacetate, mol wt 148.05, mp 350°C, is a fine crystalline powder, prepared from aluminum metal. It is used for fabric water repeUency and in the tanning of coUagen tape for surgical sutures (10). 

Aluminum acetylsaHcylate is a tasteless, nonbasic, stable, alternative therapeutic salt to aspirin (83). Also called aluminum aspirin, it is an insoluble white to off-white powder prepared by reaction of aluminum isopropoxide with sodium acetylsaHcylate in an organic solvent. The product precipitates from the reaction mixture (83). Standards requke that aluminum aspirin contain not less than the equivalent of 80% aspirin, corresponding to 90% purity on an anhydrous basis. The aluminum oxide assay must be 12—17% (81). 

Sintered Cells. Tlie fabrication of sintered electrode batteries can be divided into fwe principal operations preparation of sintering-grade nickel powder preparation of the sintered nickel plaque impregnation of the plaque with actwe material assembly of the impregnated plaques (often called plates) into electrode groups and into cells and assembly of cells into batteries. 

Chromium carbide is important in powder preparations designed for thermal spray apphcations of corrosion and wear-resistant coatings on tool and machine parts. Lower carbon carbides of chromium are important in hardfacing tods and electrodes for weld-apphed ovedays on machine wear surfaces. However, these carbides are usually formed in situ from Cr and C in the rod and not added as preformed carbides. The properties of Ci2C2 are hsted in Table 2. 

Powder Preparation. There are several routes to preparing SiC powders having variable purity levels, crystal stmcture, particle size, shape, and distribution. Methods that have been examined include growth by sublimation from the vapor phase, carbothermic reduction, and crystallization from a melt. 

Soluble impurities can be extracted by washing with deionized or distilled water foUowed by filtration (1,12,26). Powders prepared by wet chemical synthesis are often washed and filtered for purification prior to use. The dewatering (qv) process can be enhanced by pressure filtration. Organic solvents can be used to remove water-insoluble impurities and wash-water sensitive materials. 

Dehydrated Beets. This color additive is defined as a dark ted powder prepared by dehydrating sound, mature, good quality, edible beets. 

Bronze powder [12597-70-5]—Cl Pigment Metal 2, Cl No. 77400. A very fine metallic powder prepared from alloys consisting principally of virgin... 

The contact an e or adhesion tension of a binder solution with respecd to a powder can be determined from the slope of the penetration profile. Washburn tests can also be used to investigate the influence of powder preparation on penetration rates. The Bartell cell is related to the Washburn test except that adhesion tension is determined by available gas pressure which opposes penetration. [Bartell Osterhof, Ind. Eng. Chem., 19, 1277 (1927).]... 

The live fireflies are dried over calcium chloride in a vacuum desiccator, and then their lanterns are separated by hand. An acetone powder prepared from the dried lanterns is extracted with boiling water. The cooled aqueous extract is extracted with ethyl acetate at pH 3.0, and the ethyl acetate layer is concentrated under reduced pressure. The concentrated luciferin is adsorbed on a column of Celite-Fuller s earth mixture. The column is washed with water-saturated ethyl acetate, and eluted with alkaline water at pH 8.0-8.5. The aqueous eluate of luciferin is adjusted to pH 3.0 with HCl and luciferin is... 

The overall manufacturing process of / "-alumina tubes can be subdivided into the production stages powder preparation,... 

Kato, A., Study of Powder Preparation in Japan, Ceramic Bulletin, 66(4) 647-650 (1987)... 

Fig. 1. XRD pattern of naaosized TiOj powders prepared at different HNOj concentration(a) and TENOH concentration(b) synthesized at 180t)(a) and 160 t (b), dried at lOSt).

Table 1. Physical properties of nanosized TiOj powders prepared at different HNO3 and TENOH concentration and their photocatalytic activity...

Poetschke (1925) patented a dental silicate powder prepared by fusing zinc silicate with calcium fluoride. This is a kind of silicophosphate cement (Section 6.6). Thomsen (1931) attempted to formulate a water-setting dental cement. Heynemann (1931) included lithium salts in the flux and Brill (1935) included them in the liquid. 

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