Sintering technique

Porous parts and bearings are made by both the press and sinter techniques, whereas filters are made by loose powder sintering. The metals most commonly used for P/M porous products are bron2e, stainless steel (type 316), nickel-base alloys (Monel, Inconel, nickel), titanium, and aluminum. 

Metalworking, such as swaging, drawing, rolling, etc, may also be performed on slabs or ingots of other metals prepared by any of the consoHdation and sintering techniques described. 

Barium carbonate also reacts with titania to form barium titanate [12047-27-7] BaTiO, a ferroelectric material with a very high dielectric constant (see Ferroelectrics). Barium titanate is best manufactured as a single-phase composition by a soHd-state sintering technique. The asymmetrical perovskite stmcture of the titanate develops a potential difference when compressed in specific crystallographic directions, and vice versa. This material is most widely used for its strong piezoelectric characteristics in transducers for ultrasonic technical appHcations such as the emulsification of Hquids, mixing of powders and paints, and homogenization of milk, or in sonar devices (see Piezoelectrics Ultrasonics). 

Molybdenum is malleable and ductile, but because of its relatively high melting point, it is usually formed into shapes by using powder metallurgy and sintering techniques. 

These glassy materials obtained from bottom ash are also devitrified by the powder sintering technique (Barbieri et al. 20006), showing a reduction of the time and temperature of the thermal treatment and developing the same... 

The slip coating-sintering procedure can be used to make membranes with pore diameters down to about 100-200 A. More finely porous membranes are made by sol-gel techniques. In the sol-gel process slip coating is taken to the colloidal level. Generally the substrate to be coated with the sol-gel is a microporous ceramic tube formed by the slip coating-sintering technique. The solution coated onto this support is a colloidal or polymeric gel of an inorganic hydroxide. These solutions are prepared by controlled hydrolysis of metal salts or metal alkoxides to hydroxides. 

Schuessler et al. [85] of XCELLSiS (later BALLARD) presented an integrated methanol fuel processor system based on autothermal reforming, which coupled fuel/water evaporation with exothermic preferential oxidation (PrOx) of carbon monoxide. The reactor technology was based, in contrast to most other approaches, on a sintering technique. 

Coated spherical Th02- or U02-particles are increasingly utilized in the fuel of gas-cooled high temperature reactors. Their 50 to 1500 pm core of uranium(IV) oxide is manufactured using conventional sintering techniques. This is then pyrolytically coated with many layers of carbon and silicon carbide (see Section 5.7.5.1). 

In this case, the "fine" particles and the "coarse" particles were separated so that the difference in size between individual particles was minimized. That is, most of the individual particles in each fraction were almost the same size. Both the fine and coarse particles have a sintering slope of 1/2 but it is the coarse particles which sinter to form a solid having a density closest to theoretical density. This is an excellent example of the effect of pore volume, or void formation, and its effect upon the final density of a solid formed by powder compaction and sintering techniques. Quite obviously, the fine particles give rise to many more voids than the coarser particles so that the attained density of the final sintered solid is much less than for the solid prepared using coarser particles. It is also clear that if one wishes to obtain a sintered product with a density close to the theoretical density, one needs to start with a particle size distribution having particles of varied diameters so that void volume is minimized. 

G. Herrmann, H. Gleiter, and G. Baro. Investigation of low-energy grain-boundaries in metals by a sintering technique. Acta. Met., 24 353-359, 1976... 

A key point regarding electrochemical sensors is the fabrication process. These devices are usually obtained by means of sintering techniques to achieve pellet structures (Kida et al., 2000), and some authors even combine thin- or thick-film techniques to fabricate some elements such as electrodes (Salam et al., 1998). But the great potential of the use of planar configurations has made them more usual in the literature (Ramfrez-Salgado and Fabry, 2003, Fergus, 2008). Planar devices ease the fabrication process so... 

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