High pressure apparatus belt-type

Due to the constructive peculiarities in the most of widely used high pressure and temperature apparatuses including both lens and belt type ones temperature field in reaction cell has axial symmetry. Thus, one has possibility to analyze temperature conditions in reaction cells of different design by means of finite element method calculation scheme [4], Beneath we discuss the results and application of this kind of calculations of temperature fields for one possible type of lens-shaped high pressure apparatus [1],... 

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...

Two types of high-pressure apparatus are schematically illustrated in Fig. 38. They are the so-called belt-type apparams and the multianvil apparatus, both used in diamond and cBN factories. The belt type is a modified piston-cylinder apparatus. There is also an apparatus called the toroid type, whieh is a modified Bridgman-type anvil apparatus. 

Figure 38 The belt type and the multianvil type of high-pressure apparatus.

From a thermodynamic point of view, the transformation of graphite is accessible with the available experimental apparatuses, but it is kinetically impossible. Geological times, hundreds of years, are required for spontaneous formation of diamond in appropriate conditions, and kinetic factors prevent the observation of the reaction in any practical time scale. H. T. Hall has demonstrated that for graphite diamond conversion, carbon-carbon bonds must be broken in a solvent and on December 1954 realized the first synthesis of diamond, at approximately 2000 K and 10 GPa, in molten troilite (FeS) solvent, using a belt-type high-pressure-high-temperature apparatus [516-519]. Since then, many substances, minerals, and transition metals, in particular, have been... 

The design and the structure of the equipment are directly related to which of these types of radiation are used. For example, using a belt apparatus with the specific high-pressure cell shown in Fig. 7.18, electrical measurements have been made at various temperatures and pressures. 

In HPHT synthesis, a small pressure medium including furnace (heater), sample cell, and thermocouple is compressed in a high pressure apparams. There are two types of high pressure systems used for the synthesis of clathrate and intermetallic compounds, a belt-type apparams and a multi-anvil apparatus. These apparamses are also widely used for geological high pressure smdies and in sim X-ray diffraction smdies using synchrotron radiation under HPHT conditions [18]. 

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