High temperature materials processing

Barni, R. Riccardi, C. (2010). Perspective of NOx removal from numerical simulation of non-thermal atmospheric pressure plasma chemical kinetics. High Temperature Material Processes, Vol. 14, pp. 205-210... 

Nonoxide fibers, such as carbides, nitrides, and carbons, are produced by high temperature chemical processes that often result in fiber lengths shorter than those of oxide fibers. Mechanical properties such as high elastic modulus and tensile strength of these materials make them excellent as reinforcements for plastics, glass, metals, and ceramics. Because these products oxidize at high temperatures, they are primarily suited for use in vacuum or inert atmospheres, but may also be used for relatively short exposures in oxidizing atmospheres above 1000°C. 

Oxide and nonoxide refractory fibers have become essential materials for use in modem high temperature industrial processes and advanced commercial appHcations. Future process improvements, cost reductions, and performance enhancements are expected to expand the uses and markets for these specialized fibrous materials. 

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

C. K. Gupta (Guest Editor), Special Issue Chemistry and Metallurgy of Refractory and Reactive Metals and Materials Extraction and Processing, Part 1, Vol. 9, No. 24,1990 Part 2, Vol. 11, No. 14,1993, High Temperature Materials and Processes, Freund Publishing House Ltd., England. 

J. C. Sehra and A. K. Suri, Refractory and Reactive Metal Extraction by Fused Salt Electrolysis, High Temperature Materials and Processes, Vol. 11, Nos. 1-4, p. 255,1993. 

J. Thonstad, Some Recent Trends in Molten Salt Electrolysis of Titanium, Magnesium and Aluminum, High Temperature Materials and Processes, Vol. 9, Nos. 2-4, p. 135,1990. 

Anaerobic digestion, like pyrolysis, occurs in the absence of air. But, the decomposition is caused by bacterial action rather than high temperatures. This process takes place in most biological materials, but it is accelerated by warm, wet and airless conditions. It occurs naturally in decaying vegetation in ponds, producing the type of marsh gas that can catch fire. 

The synthesis of diamond is the most famous high-pressure and high-temperature industrial process, and vast quantities of this material are produced using modem industrial technology. The small synthetic crystals obtained are principally used for cutting tools and abrasives. 

Most of the successful rare earth activated phosphors comprise host lattices in which the host cation is also a rare earth. A principal reason for this relates to the optical inertness of La, Gd, Y, and Lu this is essential to avoid interference with activator emission spectra. Close chemical compatibility including amenability to substitutional Incorporation of rare earth activators are also essential features. Rare earth hosts such as oxides, oxysulfides, phosphates, vanadates and silicates also tend to be rugged materials compatible with high temperature tube processing operations and salvage. 

Sakai S, Wantanabe J, Takatsuki H, et al. 2001. Presence of PBDDs/DFs in flame retardant materials and their behavior in high-temperature melting processes. BFR 59-63. 

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