Cubic anvil

Figure 3.2 Anvil designs (a) opposed anvil (b) tetrahedral anvil and (c) cubic anvil.

Figure 6 Essential parts of high pressure apparatus of (a) the Bridgman type, (h) the belt type, (c) the cubic anvil type, (d) the 6-8 split sphere anvil type, and (e) the diamond anvil type...

A promising method for densification of combustion-synthesized products is a combination of SHS with hot isostatic pressing (HIP). This idea was first applied to the synthesis of TiB2 ceramics under a pressure of 3 GPa, which was provided by a cubic anvil press, resulting in 95% dense material (Miyamoto et al, 1984 Yamada et al., 1987). The relatively low exothermic reaction of SiC from elemental powders was also carried out under these conditions (Yamada et al, 1985), and 96% conversion to 8-SiC was achieved as compared to 36% conversion when the reaction was initiated locally. 

Beyond this range, the pressures are normally created by static pressure devices, such as piston-cylinder apparatus, solid state presses or anvil devices (opposed, tetrahedral and cubic anvil), when the sample is simply squeezed to create pressure up to 150 kbar (15 GPa) (Figure 4.9). These methods have allowed the synthesis of compounds which could not be created in any other way. However, only very small samples are produced (50 mg) in these expensive reactions, and so industrial applications of the materials produced are unlikely. 

Two multiple-anvil devices are currently in practical use. They are cubic-anvil devices and the two-stage cubic-octahedral systems. 

Fig. 1.19 Various types of cubic-anvil systems . (Reprinted with permission from Kluwer Academic Publishers.)...

Fig. 1.20 The six pistons in a cubic-anvil system . (Reprinted with permission of the publisher.)...

Fig. 1.21 The second stage of a cubic-octahedral system. Eight tungsten carbide cubic anvils with a truncation edge length of a compress an octahedral sample (reference 17).

Fig. 3.5 A thermocouple leadthrough for a high-pressure, high-temperature assembly in a cubic-anvil device. (From [6].) (1) boron-epoxy, (2) end plug, (3) sleeve, (4) cap, (5) heater-current leadthrough (gold), (6) molybdenum, (7) graphite heater, (8) platinum-rhodium thermocouple, (9) stainless-steel protective tube, (10) alumina. S and P are the sample and pressure marker (NaCI), respectively.

There are two types of multianvil compression systems, a one-stage cubic anvil system and a two-stage multianvil system. In the former system, a cubic pressure medium, as shown in Fig. 7.6b, is compressed by six anvils (Fig. 7.6a) [19]. The... 

A mini cubic anvil apparatus for high pressure NQR (and NMR) mea-... 

In order to clarify the origins of anomaly in the compression curve of CeAl2, the electrical resistance of CeAl2 was measured up to 23 GPa at room temperature using diamond-anvil cell under quasi-hydrostatic condition. According to the result obtained by cubic-anvil-type pressure device, the p P) increases with increasing pressure up to 5.5 GPa, and then decreases as shown in Figure 19B. The maximum is explained to be due to the Kondo effect, where tiie Kondo temperature Tr (which is around 6 K at ambient pressure) increases with pressure and then reaches room temperature around 5.5 GPa, that is, the pressure-induced crossover occurs in the vicinity of 5.5 GPa at room temperature. 

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