Ternary Eutectic Reaction Research Articles

Ｎｄ２Ｆｅ１４Ｂ磁石合金の焼結特性に及ぼすＣｏ添加の影響

Effects of Co addition on sintering behavior of NdFeB ternary alloy powder were investigated through observation of microstructure and measurements of DTA and linear shrinkage. In the case of NdFeB powder, shrinkage started at 940K corresponding to the appearance of a liquid phase, which was derived from ternary eutectic reaction between Nd-rich, Nd2Fe14B and Nd1.1Fe4B4 phase. Although the shrinkage below 1273K was very small because of a lack in the amount of the liquid phase, remarkable shrinking occured when sintering temperature was raised above 1273K. This is probably due to increase of the amount of the liquid phase formed by the eutectic and peritectic reactions between Nd-rich, Nd2Fe14B and Nd1.1Fe4B4 phase. In the case of Co addition the starting point of shrinkage as well as that of remarkable shrinking shifted to a lower temperature than the NdFeB ternary specimen. This can be explained by the formation of the liquid phase derived from Nd-Co compounds.

Invariant three- and four-phase equilibria in the magnesium-rich corner of the Mg-Cu-Sn ternary system

Invariant three- and four-phase equilibria in the magnesium-rich corner of the Mg-Cu-Sn ternary system have been studied by differential thermal analysis, optical microscopy, electron probe microanalysis and X-ray diffraction. The L⇋(Mg) + Mg2 Cu + Mg2Sn ternary eutectic reaction was found to be at 467 °C and at Mg−13.5 at % Cu−4.4 at% Sn. The L⇋Mg2Cu + Mg2Sn pseudo-binary eutectic reaction is tentatively located at 522°C and at Mg−26.0 at % Cu−7.7 at % Sn.

Oxidation/Reduction Melting Equilibria in the System BaO-½Y2O3-CuOx II. Powder X-Ray Analysis

AbstractX-ray powder diffraction together with several other analytical techniques have been used to characterize the phase formation and the melt compositions associated with the invariant reactions in the system BaO-½Y2O3-CuOx. In this report, the characterization results of the ternary eutectic reaction of the system, the melting of the high Tc compound Ba2YCU3O6+x, and the melting of the 'green phase' BaY2CuO5 are described. The minimum malting eutectic temperature of the system has been determined to be ≈ 925°C, which corresponds to the reaction of Ba2YCu3O6+x + CuO + BaCuO2 → Liquid. The melting of Ba2YCu3O6+x takes place at around 1015°C to yield BaY2CuO5 + Liquid. The green phase melts around 1270°C to yield BaY2O4, Y2O3 and liquid. All these melts were found to contain only a small amount of Y. Reduction of the copper was found to accompany melting.

Alloying of Ni/In/Ni/n-GaAs ohmic contacts induced by Ga-Ni-As ternary eutectic reactions

The alloying behavior of Ni and Ni/In/Ni thin-film contacts to GaAs was studied using scanning electron microscopy and scanning Auger microscopy. A liquid was observed to form in both contacts upon annealing at 820 °C for three min. The cause of this behavior was postulated to be the presence of a ternary eutectic reaction in the gallium-nickel-arsenic system. Differential thermal analysis confirmed the existence in this system of the reaction L→NiGa+NiAs+GaAs at 810 °C. It was speculated that the liquid phase observed in the Ni/In/Ni contacts was due to the rapid segregation of indium metal to the contact surface and the subsequent melting of the nearly ternary interfacial region. These results demonstrated the inadequacy of rationalizing reactions between metals and compound semiconductors in terms of constituent binary phase equilibria.

Alloying behavior of the Ni/In/Ni/n-GaAs Ohmic Contact

ABSTRACTThe interactions between Ni and Ni/In/Ni thin-films and GaAs were studied by SEM, SAM and AES. The presence of a molten phase was observed for both contacts after annealing at 820°C for 3 minutes. This behavior was rationalized in terms of the presence of a ternary eutectic reaction in the gallium-nickel-arsenic system. DTA confirmed the existence of the reaction:at 810°C. In the case of Ni/In/Ni, melting was thought to occur because of the segregation of indium metal to the contact surface and the subsequent melting of the nearly ternary interfacial region. Upon further cooling the formation of NiGa, NiAs, InxGa1−xAs and an unspecified compound Ni-In was believed to occur. The contact was shown to be either sintered or alloyed, depending upon processing conditions.

Phase relationships in Bi–In–Sn alloy system

AbstractThermal and metallographic analyses of a series of samples having compositions on or near the line joining Sn and the BiIn2 phase have been carried out. This showed the existence of a quasibinary section in the ternary diagram comprising a quasibinary eutectic of the form L → γ-Sn+BiIn2, where γ-Sn is the γ-phase of the In–Sn system. A previously unreported ternary eutectic reaction of the form L → γ-Sn+BiIn2+Bi3In5 was also found.MST/404

Constitution and magnetic susceptibility of Ni 75- xPd 25P x alloys in the crystalline, liquid, and glassy state

Crystalline Ni 75- x Pd 25P x alloys with concentrations of P <25 at% are ferromagnetic at room temperature, while splat-cooling samples of the corresponding alloys show paramagnetic behaviour. Below the glass temperature T g the glassy alloys (P concentrations of 17, 18, 19 at%) show only a weak temperature dependence of their magnetic susceptibilities; the values of x A are of the same magnitude as those in the liquid state. Up to ≈t 25 at% P the studied alloys show a ternary eutectic reaction at T E ≈t 893 K and a transition equilibrium at T U ≈t 964 K. As for the glassy alloys obtained by splat-cooling, the crystallization is connected with the appearance of several susceptibility peaks. A comparison with DSC (Differential Scanning Calorimeter) measurements is also dealt with.

18: Critical evaluation of constitution of cobalt-iron-silicon and iron-nickel-silicon alloys

The phase equilibria in the Co-Fe-Si and Fe-Ni-Si systems are reviewed in the light of available experimental data. The projection of the liquidus surface of the Co-Fe-Si system up to 35%Si contains five ternary invariant reactions (two eutectics and three other ternary transitions), and surfaces of primary crystallization for the phases αδFe, γFe, Fe2Si, β-Co2Si, α-Co2Si, α-Co2Si, and Co3Si. At higher Si contents a pseudo-binary eutectic section (experimental) between FeSi2 and CoSi2 suggests the existence of two ternary eutectic reactions and four primary surfaces corresponding to (Co, Fe)Si, FeSi2, CoSi2, and Si. For the solid state two experimental isothermal sections exist, at 1160°C (up to 25%Si) and at 800°C (over the whole composition range). In each case modifications have been introduced to achieve conformity with later work on the binary systems. The equilibria are well established and consistent with what is known of the liquid-solid equilibria. Experimental data for the liquid-solid equilibria in the Fe-Ni-Si system are too limited for the definition of an experimental projection. Detailed studies at 600°C show that a ternary cubic phase τ1 occurs at ~35% Ni, and comes into equilibrium with αδFe, γFe, Ni5Si2, and Ni2Si, and probably with the ordered bcc phases derived from the β1h and β2 phases of the Fe-Si system. Data for more Ni-rich alloys between 1000 and 450°C show that at the lowest of these temperatures ordered FeNi3 containing ~4%Si comes into equilibrium with Ni3Si containing ~7% Fe. Equilibria calculated thermodynamically at 1127 and 727°C are broadly consistent with the experimental isothermal sections. From available general information the nature of the liquid-solid equilibria may be suggested, interpreting the solid-state triangulations observed experimentally. These suggestions may be summarized by a hypothetical liquidus projection analogous to that recommended for the Co-Fe-Si system.

Ａｌ‐Ｃａ‐Ｚｎ３元系状態図の研究

Micrography, inverse rate thermal analysis, X-ray diffraction and EPMA analysis were made. Al-Ca-Zn system is composed of two quasibinary system of Al-CaZnAl and Al-CaZn13 and devided into three regions by these quasibinary systems. Two invariant reactions, peritectic and eutectic, occur in Al-CaZnAl quasibinary system at 856° and 625°C respectively. The eutectic point lies at approximately Al-4.5%Ca-7.3%Zn. Al-CaZn13 quasibinary system has an eutectic point, L=Al+CaZn13, at 546°C at approximately Al-2.4%Ca-57.9%Zn. A binary compound CaAl4 in Al-Ca system gradually changes into a ternary compound CaZnAl3. The axial ratio of its tetragonal structure increases with quantity of Zn. A ternary eutectic reaction proceeds both in Zn concentrated and dilute sides of the Al-CaZn13 quasibinary system at 543° and 380°C respectively.

Microstructure of ternary eutectic alloys in Bi-Cd-In system

Abstract Two ternary eutectic reactions are known to occur in the Bi-Cd-In ternary system: one takes place at 334.6 K and the other at 350,6 K. Experiments were conducted to determine the microstructures that result from these eutectic reactions, as well as the phases present and the volume fraction of each phase. The phases present in the 334.6 K eutectic are the major phase (BiIn2), Cd solid solution, and an In rich phase which subsequently decomposes eutectoidally. The room temperature In phase is α In. Lamellae of both minor phases are embedded in the major phase with a configuration ABCBA…, similar to that of the Cd-Pb-Sn ternary eutectic. A represents the BiIn2 phase, B the In rich phase, and C the Cd rich phase. The measured volume fractions are 60%BiIn2 4%Cd, and 36% In rich phase. The phases present in the 350.6 K eutectic are BiIn2, BiIn, and Cd solid solution. The structure, which is not regular, consists of the major phase (BiIn2) in which are embedded perforated plates of the BiIn phase and t...

Constitution of the Lead-Tin-Strontium System up to 36 Atomic Percent Sr

The constitution of the Pb-Sn-Sr system from the Pb-Sn binary up to 36 at. pct Sr was determined by differential thermal analysis, metallography, microprobe analysis, and X-ray diffraction. Pb3Sr forms a continuous series of solid solutions with Sn3Sr, and is referred to here as the8 phase. Sn4Sr was the only other intermetallic phase found and is designated here as γ. A eutectic-like trough is formed between (Pb) and δ. It originates at 1.0 at. pct Sr and 324.5 °C (the (Pb)/Pb3Sr eutectic) and falls monotonically to ~75 at. pct Pb, 24.5 at. pct Sn, and 0.45 at. pct Sr at 283 °C. At 283 °C, a Class II, four-phase reaction occurs: L + δ→ (Pb) + γ. A eutectic-like trough between (Pb) and γ falls from the four-phase plane at 283 °C to the ternary eutectic at ~26 at. pct Pb, ~74 at. pct Sn and <0.3 at. pct Sr at 182 °C. The ternary eutectic reaction is L → (Pb) + (Sn) + γ.

Cu-Pb-Sn Ternary System: Low Cu Additions to Pb-Sn- Binary System

ABSTRACTA portion of the Cu-Pb-Sn ternary diagram was determined experimentally. The investigation was concentrated on the high Pb corner and, to a lesser extent of alloys from Sn to the binary Pb-Sn eutectic. The experimental techniques used were thermal analysis, metallography, and electron microprobe analysis. A new technique for determining liquidus temperatures was used. For the high Pb region the proposed ternary eutectic at 0.06 Cu 0.02% SnPb (all compositions are in weight %) was not observed. For most alloys the primary crystallization phase was Cu3Sn. It was shown that Cu6Sn5 exists in the solid state; for high Sn alloys, it was observed that the addition of Pb reduced the decomposition temperature of Cu6Sn5. A ternary eutectic reaction near the binary Pb-Sn eutectic was confirmed, and the temperature of the ternary eutectic was 1°K below that of the binary eutectic. Liquidus temperatures as well as other reactions detected by thermal analysis will be presented.

Partial phase diagrams for the water—cadmium nitrate, water—silver nitrate and water—cadmium nitrate—silver nitrate systems

Sub-ambient differential scanning calorimetry has been used to determine partial binary phase diagrams for the water—silver nitrate and water—cadmium nitrate systems. Both systems are shown to be eutectic with eutectic temperatures of 263 ± 0.5 K and 256.5 ± 0.5 K for the water—silver nitrate and water—cadmium nitrate systems, respectively. The eutectic compositions are at approximately 40.5 wt.% nitrate for each system. The freezing of ternary solutions containing a fixed silver nitrate/cadmium nitrate ratio but increasing concentrations of total nitrates are explained in terms of a partial ternary system containing two binary eutectic systems and a ternary eutectic reaction. The ternary eutectic temperature is shown to be 254 ± 0.5 K.

Thermal analysis of Ga-In-Sn system

Thermal analysis has been used to determine the liquidus and characterize the reactions in the Ga-In- Sn system. A reaction of the type liq + (In) ⇄ β >+ (Ga) was shown to occur at 13°C, and the ternary eutectic reaction liq ⇄ (Ga)+β+(Sn) at 10.7±0.3°C. A quasi-peritectic reaction liq +γ ⇄ β + (Sn) is postulated but was pot located experimentally: it is believed to occur in alloys containing less than 1 wt-% Ga with a reaction temperature above 110°C. A quasi-peritectoid reaction β + (Sn) = (Ga) + γ is also postulated. The ternary eutectic occurs at the composition 66.0Ga-20.5In-13.5 wt-%Sn.

Comparison of the low-temperature crystallization of glasses in the ternary systems H2O-NaCl-dimethyl sulfoxide and H2O-NaCl-glycerol

Differential thermal analysis studies have resulted in quantitative evaluation of the transformation kinetics of unstable glassy phases formed during cooling of solutions from equivalent isoplethal sections in the H2O–NaCl–dimethyl-sulfoxide (DMSO) and H2O-NaCl-glycerol ternary systems. These ternary systems are of particular importance in the field of cryobiology, where knowledge of glassy phases may be especially crucial for long-term storage of biological materials at cryogenic temperatures. Activation energies for devitrification of glasses in both systems have been determined to be approximately 13 kcal/mole. The glasses were found to have approximately equal long-term stabilities. The DMSO-containing glasses appear to be more complex than glycerol-containing glasses because of the occurrence of a relatively high-temperature ternary eutectic reaction. The study of these systems appears to be a unique area for the cooperation of physical and biological scientists.

Thermal Analysis of the Ag–Au–Sn Ternary System in the Region from 20 to 100% Sn

Abstract Automated thermal analysis has been used to determine the liquidus and to characterize the reactions in the Ag–Au–Sn ternary system at tin contents from 20 to 100 wt.-%. A quasi-binary eutectic occurs at 370° C between AuSn and ζ. Four invariant reactions were identified: a ternary quasi-peritectic reaction, liquid + ζ ⇌ ɛ + AuSn, at 351° C; a second ternary quasi-peritectic reaction, liquid + AuSn ⇌ ɛ + AuSn2 at 294° C; a third ternary quasi-peritectic reaction, liquid + AuSn2 ⇌ ɛ + AuSn4 at 240° C; and a ternary eutectic reaction, liquid ⇌ ɛ + Sn + AuSn4 at 206° C.

Morphologie de l'eutectique orienté CoCoAl et influence d'une addition de nickel

The oriented eutectic CoCoAl shows two structural peculiarities. The interfibre spacing λ, is about ten times larger than that of most other similar fibrous eutectics, and the volume percentage of the fibrous Co phase can be exceptionally high, as much as 71%. The addition of nickel to the CoCoAl eutectic leads to a monovariant ternary eutectic reaction, and the growth morphology is considerably modified. These observations are explained in terms of a solid state diffusion mechanism and the modification of the phase diagram due to the addition of nickel: increase in Δ C, difference in composition between the two phases at the eutectic temperature. This example shows the interesting possibilities presented by monovariant ternary eutectic reactions providing an extra degree of freedom in the search for eutectic structures for special applications.

Th-N-O phase diagram

Phase boundaries in the Th-ThO 2-Th 3N 4 phase region were determined micrographically. The monotectic previously reported to exist in the binary Th-ThO 2 system is concluded to exist only at temperatures of 2800 °C and above and at nitrogen atom fractions of less than 0.1. With increasing temperature, solubility of ThN in ThO 2 at the ThO 2-ThN pseudobinary first becomes detectable (ca. 0.5 mole percent ThN) at about 2550 °C. The solubility increases with increasing temperature and reaches the value of 10 mole % ThN in 100 torr nitrogen at 2660 ± 50 ° C. Molar solubilities of Th and ThO 2 in ThN (coexisting with thorium and ThO 2) are substantially equal and range from 0.02 mole % at 1600 °C to 0.06 mole % at 2100 °C to zero at 2600 °C and above. A ternary peritectic reaction is postulated to occur at 1760 ± 40 ° C involving the phases ThO 2, ThN, β-Th, and liquid. A ternary eutectic reaction occurs at 1690 °C between the phases ThO 2, liquid, and postulated nitrogen-rich β-Th and nitrogen-lean β'-Th phases at the atom fractions of X o = 0.04, X N = 0.015, and X Th = 0.945.

The system Ag-Fe-S: Phase equilibria and mineral assemblages

Phase relations in the Ag-Fe-S system were determined from 700 to 150 °C by quench experiments with the use of evacuated, sealed, silica tubes as reaction vessels; these data were then used to interpret various aspects of natural occurrences of Ag-Fe-S minerals (e.g. “argentiferous pyrite”). The assemblages Ag2S+Fe1−xS and Ag2S+FeS2 become stable, with decreasing temperature, at 622±2 ° and 607±2 °C, respectively; their establishments involve ternary invariant conditions. The three condensed phases Ag2S+Fe1−xS+FeS2 become stable together at 532±2 °C through a ternary eutectic reaction near Ag2S in composition. An invariant reaction at 248±8 °C results in the formation of the Ag+FeS2 pair from the Ag2S+Fe7S8 assemblage, which is stable at higher temperatures. The associations of native silver and pyrite are found in certain massive sulfide deposits, whereas natural coexistence of argentite and pyrrhotite has not been documented. Experiments demonstrate the feasibility of retrograde reequilibration in ores to produce the silver+pyrite pair from argentite+pyrrhotite. Less than 0.05 and 0.1 at. % Ag are soluble in FeS2 and Fe1−xS, respectively, at 600 °C and less than 0.8 at. % Fe in Ag2S at 500 °C. Silver does not measurably affect the d10.2 values of Fe1−xS or the cell dimension of FeS2 (a25 °C=5.4175±0.0001 A). This study also demonstrates that at low temperatures the binary fugacity data are applicable to ternary assemblages of the Ag-Fe-S system because of these very limited solubilities. The presence of Fe lowers the fcc ⇆ bcc inversion temperature of Ag2S more than 50 °C; the exact amount of lowering is dependent on the associated Ag-Fe-S phases. The bcc ⇆ mono. inversion temperature, however, is not measurably affected. No ternary solid phases were encountered above 150 °C. Heating of sternbergite and argentopyrite (both AgFe2S3) mineral samples shows instability at 152 °C (e.g. partial breakdown of sternbergite in 405 days); rate studies show that a 10 °C temperature increase results in approximately a 5-fold increase in breakdown rate.

The Au-Pb-Sn ternary system

Thermal analysis, metallography, microhardness and X-ray techniques have been used to determine the AuSn-Pb-Sn partial-ternary system. A ternary quasiperitectic reaction, liquid + AuSn/aiPb + AuSn 2, occurs at 275°C. A second ternary quasiperitectic reaction, liquid + AuSn 2/aiPb + AuSn 4, occurs at 208°C and is followed by a ternary eutectic reaction, liquid/aiPb + Sn + AuSn 4, at 177°C.