Sintering development

Sintema A process for stabilizing the calcium sulfate/sulfite waste produced by FGD so that it may be used for landfill. The waste is mixed with ash from a coal-fired power station, pelletized, and sintered. Developed in the 1970s by Battelle Columbus Laboratories, OH, under contract with Industrial Resources. See also Fersona. 

The homopolymer of HBA was first successfully prepared in 1963 by Economy and coworkers at Carborundum Co. (Economy, 1989). The goal was to prepare new types of high temperature polymers that were proces-sible by techniques such as compression sintering developed at Carborundum rather than by expensive solution processes normally used for high temperature polymers. By carefully designed polymerizations of phenyl 4-hydroxybenzoate, they were able to synthesize poly(4-hydroxybenzoate). The product was very stable in air even up to 400 °C and could be compression sintered at 400 °C under 10,000 psi to yield specimens with a flexural... 

Worth mentioning is also the wider trans-European collaboration which exists in the area of reactor safety research through many bilateral and Community programmes which are described in the Joint Safety Research Index (FP-4 concerted action JSRI). These RTD programmes are also described in the homepage http //www-is.ike.uni-stuttgart.de/sinter developed by the R D Network on Safety-Related Innovative Nuclear Reactor Technology (FP-4 project SINTER). 

In liquid-phase sintering, densification and microstmcture development can be assessed on the basis of the liquid contact or wetting angle, ( ), fonned as a result of the interfacial energy balance at the solid-liquid-vapour intersection as defined by the Young equation ... 

Since the 1960s, the quaUty of M-ferrite manufactured has improved continuously, while the price has decreased considerably. Decisive progress in quahty was obtained by the appHcation of sinter additives (90), the introduction of pressing in a magnetic field (23), and the use of Sr instead of Ba, in combination with a sophisticated appHcation of Si02 (91,92). Important contributions to price reduction came from the development of fast multiple-die... 

Aqueous dispersions are used for spinning PTEE fibers. The dispersion is mixed with a matrix-forming medium (116,117) and forced through a spinneret into a coagulating bath. The matrix material is removed by heating and the fibers are sintered and drawn molten to develop their full strength. 

Other Le d Smeltings Processes. Stricter regulations concerning lead emissions and ambient lead in ak levels (see Airpollution), and the necessity to reduce capital and operating costs have encouraged the development of alternative lead smelting processes to replace the sinter plant—blast furnace combination. 

The process is used for ferrous P/M stmctural parts that have densities of at least 7.4 g/cm and mechanical properties superior than those of parts that have been only compacted and sintered. Depending on the appHcation, the porous matrix may be infiltrated only partially or almost completely. Copper-base alloy infiltrants have been developed to minimise erosion of the iron matrix. 

Reactive aluminas have enabled 85, 90, and 95% -AI2O2 ceramics to be upgraded (16,17), because they could be sintered without fluxes in the temperature range of about 1723—2023 K, rather than 2073—2123 K. Advances in microminiaturization of components for the electronic, computer, and aerospace industries have been directly related to the development of low soda and reactive aluminas (18). 

A wide range of cutting-tool materials is available. Properties, performance capabilities, and cost vary widely (2,7). Various steels (see Steel) cast cobalt alloys (see Cobalt and cobalt alloys) cemented, cast, and coated carbides (qv) ceramics (qv), sintered polycrystalline cubic boron nitride (cBN) (see Boron compounds) and sintered polycrystalline diamond tbin diamond coatings on cemented carbides and ceramics and single-crystal natural diamond (see Carbon) are all used as tool materials. Most tool materials used in the 1990s were developed during the twentieth century. The tool materials of the 1990s... 

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