Sintered powder technology

Compo, P., Pfeffer, R., and Tardos, G. I., Minimum Sintering Temperatures and Defluidization Characteristics of Agglomerating Particles, Powder Technology, 51(1) 87-103 (1987)... 

Francis, A. A., Rawlings, R. D., Sweeney, R. Boccaccini, A. R. 2002. Processing of coal ash into glass-ceramic products by powder technology and sintering. Journal of Glass Technology, 43, 58-62. 

The foundry technology does not admit the manufacture of dimensionally precise products of complex shapes. For this reason, sintered basalt technology has been developed for the manufacture of nozzles, drawing dies, dies for auger brick machines, etc., where the materials exhibit a resistance to abrasion still higher than that of cast basalt. The fused basalt powder is mixed with a plasticiser and pressed the pressings are sintered in an electric tunnel kiln at 1120 to 1140 C. 

Fabrication Technology. Stabilizing additives must be uniformly distributed within the starting powders for zirconia ceramics. Homogeneous distribution can be attained by controlled coprecipitation of hydroxides which are then decomposed by calcination yielding powders of fine particle sizes. Active sinterable powders are produced commercially, usually by hydrolysis of a mixture of ZrOCl and YC13 to precipitate the mixed... 

The sintering process is of particular importance in powder technology, although here the particles arc usually somewhat larger (> 30 jxm) than the conventional colloid range. 

The aim of this paper is to study the evolution of stmcture in the course of laser sintering of fine Si02 powder. It should be noted that there are some technical difficulties in the study of sintering kinetics in case of traditional powder technology when the long time furnace sintering is used. It is especially difficult to carry out the study using such technique in the case of nanopowders. 

It is known that defects reduce the strength of brittle materials due to stress concentrations, which cannot relax by plastic deformation, as in metals. However, there is also evidence that the flaw population has a similarly strong impact on the hardness. The most promising way to develop new tool materials with improved hardness, wear resistance, and reliability is to reduce the grain size in the sintered microstructures an approach which requires the use of increasingly fine-grained raw materials, be it within the framework of advanced powder technologies or of sol/gel or precursor approaches. 

The feasibility of the powder technology approach for obtaining layered cylindrical compacts from industrial silicate wastes, e. g. cullet glass and vitrified incinerator filter ash, was demonstrated [60], as shown in Figure 9. The materials underwent pressureless sintering after being compacted uniaxially in a die. They did not exhibit processing microcracks or other microstructural defects at the core/outer layer interfaces. 

The strengthening of ceramics is of great importance for engineering applications, especially at elevated temperamres. Various production processes exist most are based on powder technology and various sintering techniques (after the preparation of a green structure), but fusion or molten processes are also possible, albeit rarely used. Whatever the production technique may be, the aim is to attain a high-density product with minimal flaws (pores, microcracks, etc.). 

Except for a small introduction in the section on aqueous dispersions, high MW PTFE is one perfluoroplastic which is not covered in this chapter. This is because, in the strictest sense, resins of high MW PTFE are not melt processible. Granular PTFE resins are processed by sintered metal technology techniques. PTFE fine powders are processed by paste extrasion techniques. The structures created with the use of these resins can be quite similar to melt processible perfluoroplastic parts or can be very... 

At the same time, this effect leads to an accelerated sintering, which in turn results in the growth of contacts between the particles and in structure strength enhancement (Figure 7.67) [110]. For powder technology, this means that in order for one to lower the sintering temperature of porous... 

In this regard, the relatively novel Spark Plasma Sintering (SPS) technology, where the starting powders to be only consolidated or also simultaneously reacted are crossed by an electric pulsed current (Orru et al., 2009 Munir et al, 2011), provides a convenient alternative to overcome the drawbacks above. Indeed, the... 

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