Hot isostatic pressing technique

BN powder is used to produce lubricants for high pressure purposes [115-117], for polishing materials, as well as for HIP (hot-isostatic pressing) techniques to prevent reactions between the powder mixture and the mold. 

Special sintering procedures are necessary to produce the transparent La-doped ceramics . In particular, grain and pore sizes must be controlled. Hot pressing and hot isostatic pressing techniques are also used... 

High-pressure treatments were carried out in two units a hot isostatic press (HIP) and a multiple anvil-type high-pressure generator. The powder sample for HIP treatment were pelletized and sealed in Ag tubes in vacuo, and was then sintered at 0.15 GPa and 823 K for 2 h in N2. High pressures up to 5 GPa were applied to the powder sample in the cubic/ octahedral anvil apparatus according to a technique described elsewhere.34 Briefly, the raw powder sample was packed into a BN capsule and placed at a center of the inner octahedral anvils with pyrophyllite pieces as... 

Another method is to apply isostatic pressure and hot-isostatic pressing (HIP), now being another established technique. This technique is a very attractive because it offers possibilities of making dense SiAION ceramics with a negligible residual glassy grain boundary phase and hence better high-temperature properties. However, HP and HIP techniques are very costly. 

Another technique makes use of ultra-fine powders sintered under stress-assisted conditions so the sintering temperature is reduced,38 for instance hot-isostatic pressing, hot pressing, sinter forging, or techniques with fast... 

The wet procedure described above and based on precipitation of microcrystals from the solution makes possible to introduce gas molecules in the lattice of C60 at room temperature and atmospheric pressure. In contrast to hot pressing method, which could be used only for incorporation of chemically inert molecules to the fullerenes, low temperature technique allow us to synthesize for the first time fullerene microcrystals containing chemically active molecules like oxygen. The molecules of 02, N2 and Ar atoms occupy octahedral lattice sites in C60 microcrystals causing the lattice parameter increase. Ar interstitial fullerene obtained by precipitation was found to exhibit much higher thermal stability then that produced by hot isostatically pressing method. 

Next to mechanical properties, the most important characteristics of a carbon-carbon composite(C/C) are thermal conduction and thermal expansion. In this paper, several investigations have been made into carbon fiber arrangement relationships for different carbon-carbon composite materials. Pitch-derived carbon matrix-carbon fiber composites have been used, processed by means of the hot isostatic pressing (HIP) technique for converting pitch into a dry carbon fiber preform. Repeated HIP cycles are required to build the composite matrix up to an acceptably high density/low porosity for deployment in severely ablative environments. 

The relation of sample preparation conditions, including oxygen concentration, annealing and hot isostatic pressing, to the superconducting critical temperature of the title materials is described. New synthetic materials are examined and characterized by a variety of techniques, including magnetic susceptibility measurements, ESR, electron microscopy and X-ray diffraction. 

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