Sinter composition

A number of low sintering compositions have been based on PbFe0 55W0 )Nb0 3503. A typical er-T characteristic is shown in Fig. 5.47. er is greater than 104 between — 8 and + 45 °C but is greatly reduced when d.c. fields are applied. Since in many applications the d.c. field is less than 0.2MVm-1 its effect is not of great importance. 

A.F.Lisovsky, Migration of Metal Melts in Sintered Composite Materials [in Russian], Naukova Dumka, Kiev, 1984. 

CGO film has been used as the protective layer to reduce the reaction between YSZ and the La- and Sr-containing cathodes, which can form La2Zr207 and SrZrOj. These compounds exhibit a much higher resistance than YSZ. Figure 10.5 illustrates a plot of d spacing of the YSZ phase and CGO phase as a function of annealing temperature. Over the composition ranges used in this study, all of the sintered compositions... 

Cylindrically converging shock waves on powders were used to make mixtures of diamonds and hBN. BN fiber reinforced Zr02 was described . A nanostructured composite of magnetic particles of FOj N in a nonmagnetic matrix of BN is made via an inorganic geP. Fabrication of BN-B4 composites was reported . Consolidation of novel sintered composites formed from high pressure crystallization of amorphous ceramics was also described. The literature discusses other ceramics reinforced with BN fibers, as welF . ... 

Ceramic parts are often made from finely powdered components which are shaped by a pressure agglomeration technique and then sintered by the application of heat. In some cases this simple technique is not applicable because the powders may not sinter together, the sintering temperature or atmosphere requirements may be impractical or uneconomic, or a base material may not be readily available or may decompose under normal sintering compositions. In some of these cases, reaction sintering may offer the possibility of making sound ceramic bodies, often also with high density, which are impossible or at least difficult to produce by other methods [B.12c]. 

Figure 11 shows that all the final compositions converge on the line that represents excess MgO added to the stoichiometric PMN (point A). For another series of compositions B-H, we maintained the relative concentration between Mg and Nb and varied the concentration of PbO. After sintering, compositions B-H all converged to the same final composition. These results indicated that... 

For high-temperature applications, carbides are used as pure-material sintered parts or in a Co/Mo/W/carbide sintered composite. They outperform standard alloys and superalloys in rocket nozzles and jet engine parts where erosion resistance at... 

The most widely used transition metal carbide is tungsten carbide, hexagonal WC, which is employed as the hard constituent in WC-Co hardmetals. Such hardmetals are sintered composite materials with 80-90% of hard particles such as WC embedded in a ductile binder phase such as Co. For these apphcations WC combines a number of... 

Representative as-cast tapes, single slices of the tape, stacked slices with 30 layers, and pressed slices are shown Fig. 4.38a [162]. The thickness of the tapes was about 100 pm. Figure 4.38b shows a green body and a sintered YAG transparent ceramics. After the binder removal and cold isostatic pressing procedures, the diameter of the disk was reduced from 20 mm to about 18 mm, which was further shrunk to about 15 mm after sintering. Composite-structured YAG ceramics with a thickness of 1.0 mm exhibited high optical quality. 

Biocompatible high-strength ceramics have recently been obtained from hot-pressed mixtures of hydroxyapatite and zirconia. Sintered composites are reported to have excellent fatigue resistance [43-45]. 

Fig. 4-28. Wear characteristics of dense boron nitride-based sinters/composites in turning KhVG steel (58-60 HRCe). 1) Niborite, 2) Kiborite, 3) Sumiboron-200, 4) Hexanite-R, 5) Amborite [56].

The composition of blast furnace coke with respect to its Ume, silica and alumina contents also needs to be taken into account when calculating the required sinter composition and corresponding flux additives to give the required blast furnace slag composition. 

In this example 40 per cent of the snlfur reports to the blast furnace gas, but this proportion will greatly depend on sinter composition. 

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