Reaction Sintering of β-Si3N4/α'-Sialon Ceramics

ABSTRACTCompositions in the α'-SiAlON-√-Si3N4 solid solution region in the system Si,Al,Y/N,O which contained a third phase as a sintering aid were prepared. Mixtures of starting materials were reaction sintered to full densities without applied pressure. Phases were identified and lattice parameters of β' and √ph ases were measured and compared with standards. The results were used to construct β'-SiAION-√-Si3N4 solidsolution tie lines in the two phase region. As expected, the specimens with a higher β'-SiAION content showed higher hardness and lower toughness values.

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Microwave dielectric properties of (1 − x)Cu3Nb2O8−xZn3Nb2O8 ceramics

Journal of Materials Research ◽

10.1557/jmr.2001.0204 ◽

2001 ◽

Vol 16 (5) ◽

pp. 1465-1470 ◽

Cited By ~ 39

Author(s):

Dong-Wan Kim ◽

In-Tae Kim ◽

Byungwoo Park ◽

Kug Sun Hong ◽

Jong-Hee Kim

Keyword(s):

Solid Solution ◽

Dielectric Properties ◽

Microwave Dielectric Properties ◽

Sintering Behavior ◽

X Ray Diffraction ◽

Two Phase ◽

Sintering Aid ◽

Microwave Dielectric ◽

Solid Solution Region ◽

Solution Region

The sintering behavior and microwave dielectric properties of (1 − x)Cu3Nb2O8−xZn3Nb2O8 have been investigated using dilatometry, x-ray diffraction, and a network analyzer. It was found that (1 − x)Cu3Nb2O8−xZn3Nb2O8 ceramics have a much lower melting temperature than Zn3Nb2O8 ceramics without Cu3Nb2O8 additives. Samples sintered at 900 °C for 2 h exhibited densities >97% of the theoretical density. Cu3Nb2O8 acts as a sintering aid. Two phase regions were identified with increasing Zn3Nb2O8 contents. A Cu3Nb2O8−Zn3Nb2O8 solid solution exists from 0 < x < 0.5 while a mixture of Cu3Nb2O8 and Zn3Nb2O8 exists from 0.5 < x < 1. The microwave dielectric properties correlated to the crystal structure. In Cu3Nb2O8−Zn3Nb2O8 solid solution region, the variation of dielectric properties could be explained by the structure distortion of Cu3Nb2O8 due to electronic anisotropies of Cu2+ cations.

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Microstructure and Friction of Ion Beam Induced Amorphous Ti-Pd Alloys

MRS Proceedings ◽

10.1557/proc-55-395 ◽

1985 ◽

Vol 55 ◽

Cited By ~ 1

Author(s):

J-P. Hirvonen ◽

M. Nastasi ◽

J. R. Phillips ◽

J. W. Mayer

Keyword(s):

Solid Solution ◽

Friction Coefficient ◽

Composition Range ◽

Ion Beam ◽

Amorphous Region ◽

Transmission Electron ◽

Solid Solution Region ◽

Friction Measurements ◽

Solution Region ◽

High Equilibrium

ABSTRACTMultilayered samples of Ti-Pd with linearly varying compositions were irradiated by Xe ions at 600 keV. The induced microstructures were studied by using transmission electron microscopy and Rutherford backscattering. Mixing was found to be complete over the entire composition range, resulting in amorphous or amorphous plus crystalline structures except at the palladium-rich end, where a crystalline Pd-Ti solid solution was obtained. This is consistent with the high equilibrium solubility of Ti in Pd. In addition, significant coarsening of the microstructure caused by irradiation was found in this solid solution region.Friction measurements were carried out in air and water by using a polytetrafluoroethylene pin as a counterpart. In air the friction coefficient was independent of composition and microstructure after about 2000 passes. In water, however, after 600 passes the friction coefficient reached a steady-state value with a pronounced minimum over the amorphous region. This property was unchanged throughout the remaining 10000 passes.

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Phase Equilibrium of Mg-Nd-Zn System near Mg-Nd Side at 400°C

Materials Science Forum ◽

10.4028/www.scientific.net/msf.873.18 ◽

2016 ◽

Vol 873 ◽

pp. 18-22

Author(s):

Ming Li Huang ◽

Xue Shen ◽

Hong Xiao Li

Keyword(s):

Solid Solution ◽

Phase Equilibrium ◽

Ternary Isothermal Section ◽

Phase Region ◽

X Ray Diffraction ◽

Maximum Solubility ◽

Two Phase ◽

Solubility Range ◽

Three Phase ◽

Equilibrium Alloys

The equilibrium alloys closed to Mg-Nd side in the Mg-rich corner of the Mg-Zn-Nd system at 400°C have been investigated by scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The binary solid solutions Mg12Nd and Mg3Nd with the solubility of Zn have been identified. The maximum solubility of Zn in Mg12Nd is 4.8at%, and Mg12Nd phase can be in equilibrium with Mg solid solution. However, only when the solubility range of Zn in 26at%~32.2at%, Mg3Nd can be in two-phase equilibrium with Mg solid solution. As the results, two two-phase regions as Mg+Mg12Nd and Mg+Mg3Nd and a three-phase region as Mg+Mg12Nd+Mg3Nd in Mg-Nd-Zn ternary isothermal section at 400°C have been identified.

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Structural and phase equilibria studies in the system Pt-Fe-Cu and the occurrence of tulameenite (Pt2FeCu)

Mineralogical Magazine ◽

10.1180/minmag.1985.049.353.08 ◽

1985 ◽

Vol 49 (353) ◽

pp. 547-554 ◽

Cited By ~ 28

Author(s):

M. Shahmiri ◽

S. Murphy ◽

D. J. Vaughan

Keyword(s):

Crystal Structure ◽

Solid Solution ◽

Critical Temperature ◽

Grain Boundary ◽

Phase Region ◽

X Ray Diffraction ◽

Two Phase ◽

Slow Cooling ◽

X Ray ◽

Diffraction Patterns

AbstractThe crystal structure and compositional limits of the ternary compound Pt2FeCu (tulameenite), formed either by quenching from above the critical temperature of 1178°C or by slow cooling, have been investigated using X-ray diffraction, transmission electron microscopy, differential thermal analysis and electron probe microanalysis.The crystal structure of Pt2FeCu, established using electron density maps constructed from the measured and calculated intensities of X-ray diffraction patterns of powdered specimens, has the (000) and (½½0) lattice sites occupied by Pt atoms and the (½0½) and (0½½) sites occupied by either Cu or Fe atoms in a random manner. The resulting face-centred tetragonal structure undergoes a disordering transformation at the critical temperature to a postulated non-quenchable face-centred cubic structure. Stresses on quenching, arising from the ordering reaction, are relieved by twinning along {101} planes or by recrystallization along with deformation twinning; always involving grain boundary fracturing.Phase relations in the system Pt-Fe-Cu have been investigated through the construction of isothermal sections at 1000 and 600°C. At 1000°C there is an extensive single phase region of solid solution around Pt2FeCu and extending to the binary composition PtFe. At 600°C the composition Pt2FeCu lies just outside this now reduced area of solid solution in a two-phase field. Comparison of the experimental results with data for tulameenite suggests that some observed compositions may be metastably preserved. The occurrence of fine veinlets of silicate or other gangue minerals in tulameenite is suggested to result from grain boundary fracturing on cooling below the critical temperature of 1178°C and to be evidence of a magmatic origin.

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The f.c.c.+tetragonal two-phase region of the Cu–Ni–Zn system

Journal of Applied Crystallography ◽

10.1107/s0021889883010018 ◽

1983 ◽

Vol 16 (1) ◽

pp. 99-102 ◽

Cited By ~ 2

Author(s):

O. S. Mayall

Keyword(s):

Tetragonal Phase ◽

Lattice Spacing ◽

Single Phase ◽

Phase Region ◽

Unit Cell ◽

Unit Cell Parameters ◽

Two Phase ◽

Cell Parameters ◽

Tie Lines

The f.c.c. + tetragonal two-phase region of the Cu–Ni–Zn system has been delineated, and unit-cell parameters along the boundaries determined. Apparently anomalous parameter measurements prevented the determination of the tie lines. A pattern of diffraction broadening from the tetragonal phase common to both the two-phase and single-phase regions was related to the variation in lattice spacing of the tetragonal phase along the boundary. Reasons for this broadening are discussed.

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Ternary Phase Diagram of Model Dentin Adhesive Exposed to Over-wet Environments

Journal of Dental Research ◽

10.1177/0022034511423398 ◽

2011 ◽

Vol 90 (12) ◽

pp. 1434-1438 ◽

Cited By ~ 14

Author(s):

Q. Ye ◽

J. Park ◽

J.S. Laurence ◽

R. Parthasarathy ◽

A. Misra ◽

...

Keyword(s):

Phase Diagram ◽

Ternary Phase Diagram ◽

Water System ◽

Phase Region ◽

Partial Phase Diagram ◽

Conjugate Pair ◽

Two Phase ◽

Phase Partitioning ◽

Equilibrium Partition ◽

Tie Lines

When adhesives and/or composites are bonded to the tooth, water in the environment can interfere with proper interface formation. Formation of water blisters and phase separation at the adhesive/dentin interface have appeared as new types of bond defects. To better understand this problem, we determined the near-equilibrium partition of the hydrophobic/hydrophilic components when exposed to over-wet environments. Model methacrylate-based adhesives were mixed with different amounts of water to yield well-separated aqueous and resin phases. It was found that less than 0.1% BisGMA but nearly one-third of the HEMA diffused into the aqueous phase, leaving the remaining resin phase relatively hydrophobic. A partial phase diagram was created for the ternary BisGMA/HEMA/water system. All the experimental phase partitioning data were plotted, and the points lay on a binodal curve that separated the single-phase region from the two-phase region. We obtained the 3 tie lines by connecting the 2 points of each conjugate pair of the phase partitioning data from the 3 sets of tripartite mixtures. Information about solubility, water miscibility, distribution ratio, and phase partitioning behavior could be obtained quantitatively. This type of phase diagram will provide a more thorough understanding of current adhesive performance and elucidate directions for further improvement.

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Study on the Application of the Tie-Line-Table-Look-Up-Based Methods to Flash Calculations in Compositional Simulations

SPE Journal ◽

10.2118/142132-pa ◽

2013 ◽

Vol 18 (05) ◽

pp. 932-942 ◽

Cited By ~ 2

Author(s):

Wei Yan ◽

Abdelkrim Belkadi ◽

Michael L. Michelsen ◽

Erling H. Stenby

Keyword(s):

Computation Time ◽

Phase Region ◽

General Situation ◽

Shadow Region ◽

Two Phase ◽

Feed Composition ◽

Simulation Speed ◽

Recent Approach ◽

Tie Lines ◽

Tie Line

Summary Flash calculation can be a time-consuming part in compositional reservoir simulations, and several approaches have been proposed to speed it up. One recent approach is the shadow-region method that reduces the computation time mainly by skipping stability analysis for a large portion of the compositions in the single-phase region. In the two-phase region, a highly efficient Newton-Raphson algorithm can be used with the initial estimates from the previous step. Another approach is the compositional-space adaptive-tabulation (CSAT) approach, which is based on tie-line table look-up (TTL). It saves computation time by replacing rigorous phase-equilibrium calculations with the stored results in a tie-line table whenever the new feed composition is on one of the stored tie-lines within a certain tolerance. In this study, a modified version of CSAT, named the TTL method, has been proposed to investigate if approximation by looking up a tie-line table can save flash-computation time in the two-phase region. The number of tie-lines stored for comparison and the tolerance set for accepting the feed composition are the key parameters in this method because they will influence the simulation speed and the accuracy of simulation results. We also proposed the tie-line distance-based approximation (TDBA) method, an alternative method to TTL, to obtain approximate flash results in the two-phase region. The method uses the distance to a previous tie-line in the same grid-block to determine whether the approximation should be made. Comparison between the shadow-region approach and the approximation approach, including TTL and TDBA, has been made with a slimtube simulator by which the simulation temperature and the simulation pressure are set constant. It is shown that TDBA can significantly improve the speed in the two-phase region. In contrast, TTL, even with a precalculated tie-line table, is not so advantageous compared with an efficient implementation of rigorous flash. Furthermore, we implemented TDBA in a compositional streamline simulator to apply TDBA to scenarios with pressure variation across the reservoir. We also discussed how to extend TDBA to the general situation in which pressures in grid-blocks are updated dynamically.

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