Solubility Of Ti Research Articles

An age-integrated geochemical and computational phase-equilibria study from the Wangtu Gneissic Complex, N-W Himalaya, and its paleogeographic implications in Columbia assembly

The Paleoproterozoic thermal evolution of the north-Indian continental margin is debatable as the Lesser Himalaya granites are interpreted either as a subduction-zone volcanic arc or rift-related magmatism during Columbia assembly or disintegration processes, respectively. Integrated mineralogical, geochemical investigations, temperature estimates from Ti solubility in biotite and zircon, and computational phase equilibria modeling from the Wangtu Gneissic complex (WGC), Himachal Himalaya reveal peraluminous nature for most of the WGC rocks that crystallize at ~650 °C and ~ 1.0–1.1 GPa. The U-Pb ages from magmatic zircons from the WGC exhibit two prominent age clusters at 1867 Ma and 2487 Ma. The U-Pb zircon data and modeled phase equilibria for metasedimentary rock reveal the generation of S-type peraluminous magma parental to the WGC, through melting of preexisting supracrustal rocks at ~1800 Ma, within ~850–900 °C and 1.1–1.2 GPa, similar to P-T conditions observed in modern-day subduction zone settings. The results obtained from this study reveal the north Indian continental margin was an active subduction zone during the Paleoproterozoic Columbia supercontinent assembly that extends across the Himalayas.

Experimental investigation of isothermal sections at 1373 and 1473 K in the Co–Nb–Ti system

The isothermal sections at 1373 and 1473 K in the Co–Nb–Ti system were constructed using annealed diffusion couples and equilibrated alloys by using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), electron probe microanalysis (EPMA), and X-ray diffraction (XRD) techniques. Three three-phase regions, Co2(Nb,Ti) + Co7Nb6 + CoTi, Co7Nb6 + CoTi + bcc(Nb,Ti), and CoTi + liquid + bcc(Nb,Ti) were determined. Co3Nb and α-Co2Ti with a C36 crystal structure, and Co2Nb and β-Co2Ti with a C15 crystal structure at 1373 and 1473 K formed continuous solid solutions Co3(Nb,Ti) and Co2(Nb,Ti), respectively. The solubilities of Ti in Co7Nb6 and Nb in CoTi are determined to be ~11.4 at% and ~22.3 at% at 1373 K, and ~12.5 at% and ~24.8 at% at 1473 K, respectively. No ternary compounds were observed.

Predication of Solubility of Titanium in Fe-Csat-Ti Melts by MIVM

The solubilities of Ti balanced with titanium carbide and titanium carbonitride in Fe-Csat-Ti melts were predicted by molecular interaction volume model (MIVM). In order to verify the present method, the activity of Si, Mn and Ti in Fe-C-Si, Fe-C-Mn and Fe-C-Ti melts were predicted by MIVM and compared with experimental data. The results indicate that the predicted values of Si, Mn and Ti activity by MIVM are in good agreement with the experimental data, and the predictive effect of this model is better than the Wagner formalism. Considering the fact that titanium carbonitride is a non-ideal solid solution, the solubilities of Ti were predicted. The results are in reasonable agreement with the experimental data, and the prediction effect of MIVM are of better stability and reliability. Therefore, its prediction results can be used as the reliable basis of thermodynamic study for liquid iron containing Ti, and the calculations can be performed to predict at which conditions the carbides or carbonitrides will form.

The effect of Mg content and milling time on the solid solubility and microstructure of Ti–Mg alloys processed by mechanical milling

This research presents a high energy ball milling method for producing supersaturated solutions of the Ti100-xMgx (x = 10, 15, 20) composite powders containing a process control agent (PCA) under an argon atmosphere at an ambient temperature. The microstructure of the Ti–Mg solid solution during milling was analyzed by scanning electron microscope, and an X-Ray diffraction. A particle size analyzer was employed to investigate the average particle size at different milling times (12 h, 20 h, 32 h). After milling for 32 h of Ti100-xMgx (x = 10, 15, 20) composite powders, the solid solubility of the Mg in Ti reached about 0.5 wt.%, 1.14 wt.%, and 1.92 wt.%, respectively. It was found that the crystallite size of the milled powder decreased by increasing the milling time and reached the value of 4–11 nm after 32 h of milling. Moreover, the addition of the process control agent after 12 h and 20 h significantly reduced the agglomeration by cold welding. As a result, the average particle size of the dispersed composite powder Ti100-xMgx (x = 10, 15, 20) was refined to about 1 μm which indicated that the Ti controlled the final size as being a major alloying element. The maximum value of the density of green compacts was found to be 2.69 g/cm3 for Ti–10Mg.

Microstructure after Solution Annealing of the Nuclear Grade Austenitic Stainless Steel DIN 1.4970

The main objective of the present work was to characterize the phases that are present after solution annealing in the microstructure of the titanium stabilized austenitic stainless steel W.-Nr. 1.4970, developed as a candidate material for fast breeder reactor fuel cladding. The crystalline structure, chemical composition, quantity, size, morphology, and distribution of the phases present in the microstructure after solution annealing heat treatments were studied in detail with the help of several complementary techniques. Chemical dissolution of the matrix has been performed using the Berzelius solution and the extracted residue has been analyzed by X-ray diffraction in a high precision camera. Three phases have been observed and identified after solution annealing heat treatments performed in the 1090 to 1300 °C temperature range, namely: (Ti,Mo)C; Ti (N,C) and Ti4C2S2. The Ti-nitride and the Ti-carbosulfide did not dissolve in the steel matrix up to 1300 °C, on the other hand, the solubility of the (Ti,Mo)C raised strongly with temperature. A solution annealing heat treatment is recommended for the W. Nr. 1.4970 stainless steel.

Formation of clinohumite ± spinel in dolomitic marbles from the Makrohar Granulite Belt, Central India: Evidence for Ti mobility during regional metamorphism

Abstract The mobility of Ti, a member of high field strength elements, in metamorphic fluids is crucial to understand the recycling of commonly perceived nominally soluble elements and for mass-flux calculations during crustal processes. In this study, we present evidence for large-scale Ti mobility from a suite of clinohumite±spinel-bearing dolomitic marbles from the Makrohar area in central India. The studied rocks mostly contain dolomite and calcite (in subequal proportions) and a subordinate amount of forsterite. It commonly develops 1–5 cm thick, laterally continuous, mostly parallel, sometimes anastomosing, brown-colored clinohumite rich bands with variable spinel. Clinohumite has moderate Ti and F (TiO2 = 0.55–2.88 wt%; F = 0.94–1.88 wt%; n = 32). Textural and phase equilibria modeling indicate that clinohumite grew at the expense of forsterite + dolomite under static conditions due to infiltration of F- and Ti-bearing extremely H2O-rich fluids (XCO2 < 0.03), at ~5–6 kbar pressure and ~650–700 °C temperature. The Ti and F were most likely supplied by highly channelized aqueous fluids restricted within the centimeter-thick bands. The negative volume change of the reactions further facilitated fluid ingress. The lateral continuity of the bands over several meters across multiple out-crops indicates that Ti was mobile at the meter to kilometer scale. The results are in accordance with experimental studies that solubility of Ti increases in the presence of halides and imply that Ti may be much more mobile in metamorphic fluids during regional metamorphism than previously anticipated.

Improving the thermomechanical and magnetic properties of CuMnAl Heusler alloy by TiB doping

The influence of simultaneous doping of Ti and B on the thermomechanical, structural, and magnetic properties of CuAlMn Heusler alloys was evaluated in this study. The samples were prepared via induction casting, and they were characterized by X-ray diffraction, differential thermal analysis, optical microscopy, scanning electron microscopy, mechanical microhardness tests, and magnetometry. The alloys presented the austenite phase with L21 + DO3 structures. It was found that the doping of TiB reduced the average grain size and increased the amount of second-phase precipitates, which was attributed to the low Ti solubility in the austenitic matrix. A reduction in the values of Curie temperature, melting temperature, melting enthalpy, and HV microhardness was observed with the doping of TiB to the CuAlMn ternary system. It was also verified that the simultaneous doping of Ti and B changed the magnetic behavior of the CuAlMn system from paramagnetic (with weak ferromagnetic contribution) to ferromagnetic order. Our results bring to light a new alternative to doping CuAlMn alloy, and improve the structural and magnetic properties, interesting parameters for technological applications.

Experimental observations of TiO2 activity in rutile-undersaturated melts

Abstract An estimate of TiO2 activity (aTiO2melt-sat) is necessary for the application of trace-element thermobarometry of magmatic systems where melts are typically undersaturated with respect to rutile/anatase. Experiments were performed in the system SiO2-Na2O-TiO2 to develop two independent methods of estimating aTiO2melt-sat—one based on the commonly applied rutile-saturation technique and another utilizing a novel Ti-in-tridymite thermometer. It is demonstrated that the rutile-saturation model can lead to an overestimate of aTiO2melt-sat relative to TiO2 activity calculated using the solubility of Ti in tridymite (SiO2) coexisting with rutile. Overestimation via the rutile-saturation technique is due to variations in the solubility mechanisms of Ti in the melt phase as a function of Ti content. In natural systems, overestimates of aTiO2melt-sat will lead to an underestimation of crystallization temperatures by Ti-based trace-element thermobarometers. Although this study is not directly applicable to natural systems, it lays the groundwork for future research on natural composition magmas to constrain TiO2 activity in melts.

Optimization of Electrolysis Conditions for Ti Film Electrodeposition from LiF – LiCl Eutectic Molten Salt

1. IntroductionTitanium is known as a metal which has excellent properties such as high specific strength and high corrosion resistance. However, there are two problems that prevent widespread use of titanium. One is the high smelting cost and the other is the poor workability. As a method to solve these problems, titanium plating is an attractive technique because superior surface properties of titanium can be utilized. For some applications, physical vapor deposition (PVD) is practically used as a titanium plating method. However, the PVD method has high plating cost and can be used for only simple-shaped substrates. On the other hand, electrodeposition of titanium in high-temperature molten salt is a promising plating method which is expected to have lower cost and can be used for complex shaped substrates. Accordingly, there have been many reports on the titanium electrodeposition in high-temperature molten salts [1–3].We have already reported the electrochemical behaviors of Ti(III) ions and the electrodeposition of titanium in KF–KCl and LiF–LiCl molten salts [4–7]. Furthermore, we found that LiF–LiCl has an advantage for electrodepositing smooth titanium films due to its lower melting point (774 K at the eutectic composition [8]); smoother titanium films were obtained at lower temperature by suppressing grain growth of titanium [9]. Thus, in the present study, we investigated the effect of electrolysis conditions such as current density and concentration of Ti(III) ions on smoothness of titanium films in LiF–LiCl eutectic molten salt.2. ExperimentalThe experiments were conducted in LiF–LiCl eutectic molten salt in an Ar glove box at 823 K. Li2TiF6(0.50–5.0 mol%) and Ti sponge (0.33–3.3 mol%) were added to the bath and Ti(IV) ions were converted to Ti(III) ions by comproportionation reaction. Ni plate, Mo flag, and Au flag electrodes were used as the working electrode. The counter and reference electrodes were Ti rods. The potential of the reference electrode was calibrated by Cl2/Cl− potential measured at a glass-like carbon rod electrode. Samples were prepared by galvanostatic electrolysis of Ni plate substrates. The samples were analyzed by SEM/EDX after washing with distilled water and 1M Al(NO3)3 aqueous solution to remove adhered salts.3. Result and DiscussionThe electrodeposition was carried out by changing the added amounts of Li2TiF6from 0.50 to 5.0 mol% and Ti sponge from 0.33 to 3.3 mol%. The cathodic current density was also varied from 25 to 1000 mA cm−2. The surface roughness of the obtained samples was measured by SEM. As a result, smooth Ti films were obtained at high Ti(III) concentrations and low current densities. As a typical example of the smooth film, Fig. 1 shows an appearance of the sample prepared at 50 mA cm−2 and 60 C cm−2 after addition of 3.0 mol% Li2TiF6and 2.0 mol% Ti sponge. The electrodeposited titanium film had metallic luster. Fig. 2 shows a cross-sectional SEM image of the film, indicating the smooth and compact deposit.In the poster session, the solubility of Ti(III) ions will be presented. Also, the effects of Ti(III) ion concentration and cathodic current density on the morphology will be discussed.AcknowledgementThe present address of Kouji Yasuda is Graduate School of Engineering, Kyoto University.

Correction to: Discontinuous precipitation of rutilated quartz: grain-boundary migration induced by changes to the equilibrium solubility of Ti in quartz

Correction to: Discontinuous precipitation of rutilated quartz: grain-boundary migration induced by changes to the equilibrium solubility of Ti in quartz

Reactivity of the Ti–Al system: Experimental study and molecular dynamics simulations

The reactivity of the Ti–Al system was investigated experimentally in the case of reactive laminated particles produced by high energy ball milling. The ignition temperature for a self-sustaining reaction was measured as a function of the heating rate. By means of the Kissinger analysis, two activation energies were evaluated. The first one is associated with the solid-state transformation at the interface below the melting point of Al. The second one corresponds to the exothermic dissolution of Ti into Al liquid together with the formation of TiAl3. A complementary microscopic approach was developed in order to detect all elemental processes associated with the reactivity of the Ti–Al system in composite materials. Above the melting temperature of Al, the exothermic dissolution of Ti into the liquid layer starts and induces a self-sustaining behavior until the reaction is complete. The dissolution step is limited by the low solubility of Ti in Al. The formation of the intermetallic compound TiAl3 was observed. The microscopic analysis of the dissolution at the interface explains some specific features of reactive particles.

Discontinuous precipitation of rutilated quartz: grain-boundary migration induced by changes to the equilibrium solubility of Ti in quartz

We experimentally investigated changes to the titanium concentrations of quartz-rich rocks caused by grain-boundary migration. Synthesis experiments were performed to make high-Ti quartz starting materials for usage in recrystallization experiments. We isothermally recrystallized quartz starting material in separate experiments at 10–25 kbar to reduce the solubility of Ti in quartz. Microstructural and geochemical results indicate that the high-Ti quartz starting material recrystallized to form low-Ti quartz with acicular rutile inclusions. During recrystallization, high-Ti quartz was consumed to form low-Ti quartz and acicular rutile crystals precipitated behind moving grain boundaries via the discontinuous precipitation unmixing process. Experimentally imposed changes to the equilibrium solubility concentration of Ti in quartz by amounts as low as ~ 0.02 weight % (200 µg/g or ppm by weight) created a free energy driving force of 8.7 kJ/mol that was sufficient to drive large-scale recrystallization of the quartzites. Microstructures of relict grains of the high-Ti quartz starting materials are characterized by cuspate and irregular grain boundaries, whereas new quartz grains exhibit subhedral to euhedral grain morphologies and abundant three-grain junctions. Discontinuous precipitation can significantly change mineral compositions, and in the absence of a free fluid phase can operate much faster than other types of mass transfer processes commonly associated with solid-state reactions.

Effect of High Undercooling on Dendritic Morphology and Mechanical Properties of Rapidly Solidified Inconel X750 Alloy

The rapid dendrite growth kinetics of Inconel X750 alloy was explored under electromagnetic levitation and free fall conditions. The dendrite growth velocity of the primary γ phase varies as a double exponential function with undercooling (ΔT). The critical undercooling for the transformation of the primary γ phase from dendrites to equiaxed grains in electromagnetic levitation (EML) and drop tube (DT) experiments is similar. With comparable undercoolings, the grain size of γ phase solidified in the DT is much smaller than that in the EML owing to the effect of large cooling rate. As the undercooling continuously increases to 230 K, the phase constitution changes from γ and precipitated phases to single γ phase. Based on EDS and TEM results, the precipitated phase is confirmed as (Ti, Nb)C phase, and the γ/(Ti, Nb)C interface is semicoherent. The compressive and nanomechanical properties of Inconel X750 alloy solidified in EML experiments were also investigated. The results show that the elastic modulus of γ phase is smaller than that of (Ti, Nb)C phase. According to the compression tests, the elastic modulus of Inconel X750 alloy is improved by high undercooling. Interestingly, the elastic modulus decreases when the undercooling is larger than 230 K, which is attributed to the increasing solubility of Ti and Nb in γ phase and the disappearance of (Ti, Nb)C phase.

Effects of Ti and High Cooling Rate on the Phase Equilibria and Properties of Ni3(Al,V) Alloys

Investigations of the Ni3(Al,V,Ti) alloys with 5 at.% Ti addition show that high quenching rates from the liquid state allow for the preservation of the metastable Ni(Al,V,Ti) solid solution at low temperatures as well as for the limitation of the eutectoid decomposition range. Annealing at the temperatures close to the eutectoid decomposition causes an increase in the amount of the Ni3Al and Ni3V equilibrium phases, as well as the precipitation of the Ni3Ti phase. The V addition reveals the ability to stabilize Ni solid solution, while Ti retards Ni3V phase precipitation but also supports the precipitation of the Ni3Ti phase, in spite of the higher than 5 at.% range of Ti solubility in the Ni3V phase. The increase in V and Ti content at the cost of a decrease in Al content strongly increases micro-hardness of the alloys crystallized at high rates. For the alloys containing predominantly V, increased ductility was noticed in the temperature range of the dissolution of Ni3V precipitates.

Titanium‐in‐biotite thermometry in porphyry copper systems: Challenges to application of the thermometer

AbstractEmpirical geothermometer dealing with Ti solubility in the Fe‐Mg biotites was originally proposed for biotites in graphitic, peraluminous metapelites containing ilmenite or rutile that equilibrated roughly at 4–6 kbar. Given that biotites are abundant in the porphyry copper systems, this geothermometer has frequently been used for the determination of magmatic–hydrothermal temperatures in the porphyry copper systems. Common associations of porphyry copper deposits (PCDs), that is, low Al content of biotite, biotite chloritization (causes the biotite to become more magnesian and to lose Ti), and biotite formation by amphibole replacement, as well as disequilibrium, local equilibrium, or re‐equilibration of biotites, especially through potassic alteration, may provide significant uncertainty in the temperatures estimated a by Ti‐in‐biotite geothermometer. In addition, besides the calibration range of thermometer for pressure (400–600 MPa), the temperatures of major sulfide precipitation in PCDs (>~400°C) does not fit with the temperature range of thermometer calibration (480–800°C). Worth noting, as confirmed by fluid inclusion data in the Sarkuh PCD, regardless of presence of mineralogical requirements, obtained temperatures of sulfide mineralization using Ti in biotite thermometer could be overestimated. This may be due to the difference between general conditions of sulfide mineralization and calibration range of Ti in the biotite thermometer for pressure and temperature, as well as the metaluminous nature of biotites in PCDs.

Metallurgical processes for hardening of 22Karat Gold for light weight and high strength jewelry manufacturing

The present work reports about the process developed for hardening 22Karat gold (Au-5.8wt.%Cu-2.5wt.%Ag). The present hardness of 22Karat gold is 85–90HV (Vickers scale). The target hardness aimed is 150HV in the final jewelry product, similar to the hardness of 18Karat gold, however without compromising luster and purity (91.7wt.%). Titanium is added as the quaternary element in micro concentrations that grain refines the as-cast structure of 22Karat gold and improves the strength of the cast jewelry products. On other hand the narrow solid solubility of Ti in Au is used to convert the 22Karat gold into age hardenable gold alloy suitable for making hand-made jewelry products. This paper reports the optimization of various process parameters in industrial scale, required for producing hard 22Karat gold containing Ti through age hardening process. In lab scale the titanium concentration required was optimized to 0.5wt.%, to obtain effective age hardenability in 22Karat gold was studied. In industry the melting and casting trials of 22Karat gold with the addition of 0.5wt.% of Ti to obtain maximum yield was performed. The annealing and cold-working operations were conducted to the Ti-22Karat gold that lead to production of hand-made bangles were studied. The age hardening treatments (Solutionizing and Artificial Aging (AA)) were conducted to the Ti-22Karat gold bangles to obtain hardness >150HV.

The Isothermal Section of the Al-Si-Ti Ternary System at 550 °C

The isothermal section of the Al-Si-Ti ternary system at 550 °C has been determined using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. Results show that there are 12 three-phase equilibrium regions in the isothermal section of the system. The maximum solubility of Si in Al3Ti is 16.4%, and the solubility of Al and Ti in Si is small. There exists only one ternary compound in the isothermal section with a composition of Al7.1-13.9Ti33.5-34.2Si51.9-59.1.

Evolution of the mechanical properties of Ti-based intermetallic thin films doped with different metals to be used as biomedical devices

This study reports the assessment of the mechanical properties of intermetallic titanium thin films, doped with different amounts of aluminium, copper, silver, and gold, aiming their use as biopotential electrodes for non-invasive physiological monitoring. The four binary thin film systems, Ti-Me (Me = Al, Cu, Ag, Au), were prepared by DC magnetron sputtering, placing different number of Me pellets on a pure Ti target. The use of a Ti-composed target gave rise to a wide range of compositions, resulting in three distinctive zones of (micro)structural features, identified in all the prepared systems. In the first zone, a Ti-rich one, the films behaved like solid solutions, developing Ti-like microstructures. As the Me/Ti atomic ratio increased, the formation of intermetallic phases played the leading role and it became possible to observe two different microstructural trends, clearly related to the Me type. This zone was identified as an intermetallic region. In the third zone, a Me-rich one, the microstructures displayed by the different films (Me/Ti > 1.0) showed to be dependent on the Ti solubility into Me. The assessment of the mechanical properties revealed an improved hardness and stiffness with the Me addition, directly related to the formation of intermetallic compounds in different degrees of crystallinity. Moreover, the adhesive strength between the substrate and the coating was higher for the films deposited in the intermetallic zone, more evident in the films prepared with Au, Cu and Ag, in this order. The hardness enhancement was especially evident for the thin films presenting microstructures typical of thin film metallic glasses (TFMGs), Ti-Au and Ti-Cu, about twice the values exhibited by the Ti-Al and Ti-Ag ones. Furthermore, the toughness of these metallic glass-like thin film systems was remarkable, more evident within the Ti-rich zone, presenting H/E ratios close to 0.1 and good elastic recoveries. In contrast, the typical columnar morphologies, combined with the brittle intermetallic structures of the Ti-Ag and Ti-Al films, proved to be less resistant to the plastic deformation (H/E ≤ 0.04), despite the improved elasticity presented by the Ag-rich films.

CALPHAD assessment of bio-oriented Ti–Zr–Sn system and experimental validation in Ti/Zr-rich alloys

The development of CALPHAD-type thermodynamic database for Ti or Zr based biomedical alloys has been spurred by the increased interest in efficiently tailoring an alloy composition to obtain high stability of β_bcc, low Young's modulus, and free of detrimental phases. However, the thermodynamic prediction is not adequate to be performed without the information of key sub-ternary Ti–Zr–Sn system. In present work, the thermodynamic assessment of Ti–Zr–Sn system is performed via a critical evaluation of phase equilibria and microstructure development in this ternary system. The partial isothermal sections at 1323 K and 1473 K with Sn content below 40 at. % are obtained by analyzing chemical compositions and crystal structures of individual phases in the annealed alloys. The composition homogeneity range of most phases is validated to favor a ternary extension paralleling to the Ti–Zr axis. Particularly, β_bcc and η phases (with the chemical composition (Ti, Zr)5Sn3+x) show complete solubility of Ti and Zr from Ti–Sn edge to Zr–Sn edge. With the database, negligible ternary solubility of Zr4Sn phase, microstructure development in the as-cast samples, and the controversial conclusions in literature are discussed. Most of the experimental findings, including equilibrium phase constitution, solidification sequence, DSC signals, projections of liquidus, are reproduced in a self-consistent way. The work moves towards the completeness of multi-component Ti/Zr thermodynamic database. It can be used for composition design of novel metastable β-type biomedical alloys.

Experimental investigation of phase relationship in Ti–Fe-Hf ternary system

Based on diffusion triple and equilibrated alloy methods, phase relations in the Ti–Fe-Hf ternary system were investigated using the experimental data obtained through the combination of optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA) techniques. Isothermal sections of the Ti–Fe-Hf system at both 1073 K and 1273 K were well constructed. There are three and four three-phase regions in these two sections, respectively. According to the present results, Hf can dissolve into FeTi at approximately 3.0% at both 1073 K and 1273 K. A continuous solid solution of Fe2(Ti, Hf) forms between the binary intermediate compounds Fe2Ti and Fe2Hf (h). Fe2Hf(c) and FeHf2 show large solid solubilities. The solubility of Ti in Fe2Hf(c) changes from 33.9% at 1073 K to 39.0% at 1273 K, while that of FeHf2 can reach up to approximately 63.0% at 1273 K. No ternary compound exists in the Ti–Fe-Hf ternary system.