Solid Gas Reaction Phase Diagram under High Gas Pressure - HIP Phase Diagram

MRS Proceedings ◽

10.1557/proc-251-3 ◽

1991 ◽

Vol 251 ◽

Author(s):

Kozo Ishizaki

Keyword(s):

Phase Diagram ◽

Partial Pressure ◽

Gas Pressure ◽

Reaction Phase ◽

Independent Variable ◽

Hip Process

ABSTRACTTo evaluate which are the stable phases under high gas pressure conditions, a solid-gas reaction phase diagram under high gas pressure (HIP phase diagram) has been proposed by the author. The variables of the diagram are temperature, reactant gas partial pressure and total gas pressure. Up to the present time the diagrams have been constructed using isobaric conditions. In this work, the stable phases for a real HIP process were evaluated assuming an isochoric condition.To understand the effect of the total gas pressure on stability is of primary importance: Two possibilities were considered and evaluated, those are: i) the total gas pressure acts as an independent variable, or ii) it only affects the fugacity values. The results of this work indicate that the total gas pressure acts as an independent variable, and in turn it also affects the fugacity values.

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Hip Phase Diagram of YBCO Type Superconductor

MRS Proceedings ◽

10.1557/proc-251-307 ◽

1991 ◽

Vol 251 ◽

Author(s):

Yuichi Sawai ◽

K. Ishizaki ◽

M. Takata ◽

A. Kuzjukevics ◽

Y. Narukawa

Keyword(s):

Phase Diagram ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Phase Formation ◽

Gas Pressure ◽

Boundary Line ◽

Temperature Phase ◽

Formation Temperature ◽

Oxidation Reactions ◽

Temperature Phase Diagram

ABSTRACTThe oxygen partial pressure - temperature phase diagram of YBCO type superconductors reported before by us showed that the YBa2Cu4Ox phase formation from Y2Ba4Cu7Oz with CuO, as well as from YBa2Cu3Oy, with CuO are oxidation reactions. The total gas pressure - temperature phase diagram shows that the YBa2Cu4Ox, phase formation temperature from Y2Ba4Cu7Oz with CuO increases with increasing the total gas pressure. On this phase boundary line, the fugacity of oxygen increases with increasing the total gas pressure even at constant oxygen partial pressure.

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Controlled partial melting during isobaric and isothermal processing of dipcoated Bi-2212/Ag tapes

Journal of Materials Research ◽

10.1557/jmr.1998.0487 ◽

1998 ◽

Vol 13 (12) ◽

pp. 3580-3586 ◽

Cited By ~ 3

Author(s):

A. L. Crossley ◽

J. L. MacManus-Driscoll

Keyword(s):

Phase Diagram ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Partial Melting ◽

Coulometric Titration ◽

Processing Route ◽

Optimum Processing ◽

Partial Pressures ◽

Titration Technique

A detailed study has been made of the control and optimization of partial melting of dipcoated Bi2Sr2Ca1Cu2O8+δAg0.1 (Bi-2212) tapes using reduced oxygen partial pressures. A coulometric titration technique has been employed to vary the oxygen partial pressure in a region of the phase diagram corresponding to binary melting, and the amount of partial melting has been quantified. Using this information, tapes have been processed using both isothermal and isobaric techniques. An optimum processing route was determined which combined isothermal and isobaric processes. Highly aligned material at the point of optimum melting was obtained.

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Effect of Isostatic GAS Pressure on Optical Quality of MgAl2O4 Spinel

MRS Proceedings ◽

10.1557/proc-251-257 ◽

1991 ◽

Vol 251 ◽

Author(s):

S.E. Hsu ◽

C.T. Wang ◽

D.S. Tsai ◽

S.J. Yang

Keyword(s):

Applied Pressure ◽

Xrd Analysis ◽

Optical Quality ◽

Gas Pressure ◽

Pressure Treatment ◽

Before And After ◽

Diffraction Peaks ◽

Bimodal Grain Size ◽

Hip Process

ABSTRACTOptical transparent MgAl2O4 spinel is obtained by processing with high gas pressure to eliminate or reduce the residual pores. Both hot–pressed and sintered specimens are post–treated by the high argon hipping process here. The densities of all the specimens before hipping are over 99% theoretical density. In the high gas pressure process, the pressure ranges from 2000 to 30000psi at 1500°C for 2hrs. The transmittance from visible to IR are measured before and after gas pressure treatment. The transparency from visible to IR increases significantly with the HIP process. When applied pressure less than 6000psi, bulk density is proportional to the logarithm of the pressure and the logarithm of the absorption coefficient is proportional to the porosity. Bimodal grain–size distribution exists in the sintered and hipped specimens but is not observed in the uniaxial–hot–pressed–only samples. XRD analysis indicates the width of the diffraction peaks in the HIP specimens is less than that in UAHP specimens. The result illustrates the HIP process improves the spinel crystallinity.

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Wear resistance of arc ion-plated chromium nitride coatings

Journal of Materials Research ◽

10.1557/jmr.1993.1109 ◽

1993 ◽

Vol 8 (5) ◽

pp. 1109-1115 ◽

Cited By ~ 101

Author(s):

Yuji Chiba ◽

Toshio Omura ◽

Hiroshi Ichimura

Keyword(s):

Phase Diagram ◽

Wear Resistance ◽

Surface Morphology ◽

Bias Voltage ◽

Gas Pressure ◽

Chromium Nitride ◽

Nitrogen Gas ◽

High Toughness ◽

Nitride Coatings ◽

Two Parameters

Wear resistance of arc ion-plated chromium nitride films has been studied. It has been found that texture and phases composing the films depend much on bias voltage and nitrogen gas pressure at the deposition. A phase diagram was constructed as a function of these two parameters, which indicated that three categories exist: CrN single, CrN and Cr2N dual, and CrN and Cr dual phased regions, respectively. Results of Falex No. 2 test showed that the wear resistance of CrN single phased films is superior to others, especially when (220) preferred orientation is developed. Since hardness and surface morphology do not differ much between these films, a high toughness of CrN single phased film is considered to make a difference by suppressing abrasion wear.

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The structural phase diagram and oxygen equilibrium partial pressure of YBa2Cu3O6+x studied by neutron powder diffraction and gas volumetry

Physica C Superconductivity ◽

10.1016/0921-4534(90)90639-v ◽

1990 ◽

Vol 172 (1-2) ◽

pp. 31-42 ◽

Cited By ~ 73

Author(s):

N.H. Andersen ◽

B. Lebech ◽

H.F. Poulsen

Keyword(s):

Phase Diagram ◽

Partial Pressure ◽

Powder Diffraction ◽

Structural Phase ◽

Neutron Powder Diffraction ◽

Equilibrium Partial Pressure ◽

Oxygen Equilibrium

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Pressure, Temperature Reaction Phase Diagram for Ammonium Dinitramide

The Journal of Physical Chemistry ◽

10.1021/jp952144j ◽

1996 ◽

Vol 100 (8) ◽

pp. 3248-3251 ◽

Cited By ~ 27

Author(s):

T. P. Russell ◽

G. J. Piermarini ◽

S. Block ◽

P. J. Miller

Keyword(s):

Phase Diagram ◽

Temperature Reaction ◽

Ammonium Dinitramide ◽

Reaction Phase

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Conversion of 124 into 123 + CuO: microstructure and phase diagram

MRS Proceedings ◽

10.1557/proc-169-245 ◽

1989 ◽

Vol 169 ◽

Cited By ~ 3

Author(s):

Donald E. Morris ◽

Janice H. Nickel ◽

Andrea G. Markelz ◽

Ronald Gronsky ◽

Mark Fendorf ◽

...

Keyword(s):

Phase Diagram ◽

Partial Pressure ◽

Flux Pinning ◽

High Strain ◽

Lattice Mismatch ◽

Partial Pressure Of Oxygen ◽

Strain Fields ◽

Pinning Centers ◽

Highly Strained ◽

Microstructural Studies

AbstractConversion of 124 into 123 + CuO is interesting because it can produce non‐superconducting CuO islands and highly strained local regions, both of which may act as flux pinning centers. Microstructural studies (TEM) show localized regions with high strain fields resulting from the lattice mismatch between 124 and 123 along the c axis. Enhanced Tc (95 K) was found in partly converted samples. The partial pressure of oxygen necessary for conversion from YBa2Cu4O8 (124) to YBa2Cu307 (123) decreases with decreasing temperatures, and below 850°C the boundary between 123 and 124 phase regions is found to fall approximately as log ρ(θ2) = 19.3 ‐22000/T. The phase diagram of the Y‐Ba‐Cu‐O system is given as a function of temperature and partial pressure of oxygen over the range between 500°C and 1000°C and 10‐6< P[O2] < 102 bar.

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