Thermodynamic assessment of the Ca–Zn,Sr–Zn,Y–Zn and Ce–Zn systems

Published experimental thermodynamic and phase diagram data for the Ca–Zn, Sr–Zn, Y–Zn and Ce–Zn systems have been critically evaluated to provide assessed thermodynamic parameters for the different phases of the systems. The parameters allow all thermodynamic properties and phase boundaries for each system to be calculated within reasonable error limits. Because a strong compound-forming tendency and pronounced minimum in the enthalpy of mixing curve is observed for the liquid phase of all the systems, the Modified Quasichemical Model (MQM) in the pair approximation has been used throughout the assessment work to treat short-range ordering in the liquid.     

Thermodynamic assessment of the Si–Zn,Mn–Si,Mg–Si–Zn and Mg–Mn–Si systems

The binary Si–Zn and Mn–Si systems have been critically evaluated based upon available phase equilibrium and thermodynamic data, and optimized model parameters have been obtained giving the Gibbs energies of all phases as functions of temperature and composition. The liquid solution has been modeled with the Modified Quasichemical Model (MQM) to account for the short-range-ordering. The results have been combined with those of our previous optimizations of the Mg–Si, Mg–Zn and Mg–Mn systems to predict the phase diagrams of the Mg–Si–Zn and Mg–Mn–Si systems. The predictions have been compared with available data.     

Experimental investigation and thermodynamic reassessment of the Fe–Si–Zn system

Based on the critical evaluation of the experimental data available in the literature, the isothermal section of the Fe–Si–Zn system at 873 K was measured using a combination of X-ray analysis and scanning electron microscopy with energy-dispersive X-ray analysis. No ternary phase is observed at 873 K. A thermodynamic modeling for the Fe–Si–Zn system was then conducted by considering the reliable experimental data from the literature and the present work. All the calculated phase equilibria agree well with the experimental ones. It is noteworthy that a stable liquid miscibility gap appears in the computed ternary phase diagrams although it is metastable in the three boundary binaries.     

Mechanical behavior of metallic glasses Mg–Cu–Y using nano-indentation

The mechanical properties of amorphous bulk metallic glassy (BMG) alloy, Mg₅₈Cu₃₁Y₁₁, are examined using nano-indentation scratching test. This study investigates the influences of different scratching conditions on the mechanical properties such as the friction force and the friction coefficient (μ) to understand the abrasive behavior of the BMG. The scratching conditions include applied normal load, depth of scratch, scratching velocity, and scratching temperature. The experimental results of the friction force, friction coefficient, hardness, and scratching morphology of BMG are characterized. The result shows that the friction force is nearly proportional to the normal load; and the friction force exhibits a slightly dependent on the scratching temperature. Then, regression analysis method is utilized to establish a formula to fit the scratching condition of BMGs. The regression analysis can be applied to model the mathematical relationship between the scratching parameters. The regression result shows a good agreement with experimental one.     

Experimental investigation and thermodynamic assessment of the Zn–Cu–Sr ternary system

Zn–Cu–Sr alloys play a crucial role in the development of biodegradable implant materials based on zinc. The current study aimed to investigate the phase equilibria of the Zn–Cu–Sr ternary system in the Cu–Zn-rich region, through experimental analysis. For this purpose, fifteen and fourteen samples were respectively prepared and equilibrated at 350 and 400 °C, to determine the isothermal sections. The equilibrated alloys were then subjected to various analytical techniques such as scanning electron microscopy (SEM) equipped with energy dispersive spectrometry analysis (EDS), electron probe microanalysis (EPMA), and powder X-ray diffraction analysis (XRD). The analysis revealed the presence of five three-phase equilibria and ten two-phase equilibria in the two isothermal sections. Differential scanning calorimetry (DSC) was used to investigate the phase transformation temperature with constant values of 8 at. % Sr and 30 at. % Cu. The obtained experimental results were used to perform a thermodynamic assessment of the Zn–Cu–Sr system especial in Zn-rich region using the calculation of phase diagrams (CALPHAD) method. The modified quasi-chemical model (MQM) was used to model the liquid solution, while the compound energy formalism (CEF) was used to represent Gibbs free energies of the solid phases. The present obtained thermodynamic parameters were found to accurately reproduce the experimentally measured phase relationships in the Zn–Cu–Sr ternary system.     

Experimental study and thermodynamic calculation of the Y–Co–Fe system

In this work, the phase equilibria of the Y–Co–Fe ternary system were studied experimentally by scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The phase transition temperatures and phase formation of Y–Co–Fe alloys were examined by differential thermal analysis (DTA) and SEM-EDS. No ternary intermetallic compounds were detected. The continuous solid solution phases Y₂(Co, Fe)₁₇, Y(Co, Fe)₃ and Y(Co, Fe)₂ were formed from the respective Y–Co and Y–Fe binary intermetallic compounds. The solubility of Fe in YCo₅ and Y₂Co₇ and the solubility of Co in Y₆Fe₂₃ were determined. Based on the experimental results determined in this work and reported in the literature, the thermodynamic calculation of the Y–Co–Fe ternary system was performed using the CALPHAD method in combination with the previous assessments of three Y–Co, Y–Fe and Co–Fe binary systems. The liquidus projection, isothermal sections and vertical sections of this ternary system were calculated. The good agreement between the calculated results and the experimental results was achieved. A set of self-consistent thermodynamic parameters for describing various phases in the Y–Co–Fe ternary systems was obtained finally, which would provide a good basis for the development of the thermodynamic database of multi-component Y–Co–Fe based alloy systems.     

Modelling the giant,Zn–Pb–Ag Century deposit,Queensland, Australia

This paper presents a combination of geometric reconstructions of the Century Zn–Pb–Ag deposit, and finite-difference modelling of coupled deformation and fluid flow. Our intention is to demonstrate that these computer-based applications represent a new approach in testing ore genesis models. We use a “visiometric” approach, utilising GoCad 3D structural and property modelling. Computer visualisation is applied to reveal metal zonations, fault distributions and timing, stratigraphic influence on zoning, and the nature and extent of metal redistribution during basin evolution and deformation. We also examine possible links between fluid flow, deformation, and mass transfer using the numerical code FLAC3D. Numerical modelling results suggest that subsurface fluid flow during basin inversion is compartmentalised, being focussed within more permeable fault zones, thus accounting for the secondary redistribution of base metals identified using the 3D reconstructions. However, the results do not explain the broad metal zonation observed. Both the spatial and numerical models suggest that Century is syngenetic, with further diagenesis and deformation producing 1–100 m-scale (re)mobilisation.     

“Ni–Zn铁氧体颗粒–光刻胶”覆盖的 片上射频电感

本文报道了采用新型"纳米颗粒一光刻胶"混合旋涂技术制作的片上射频Ni-Zn铁氧体磁膜微电感.成相良好的Ni0.3Zn0.6Cu0.1Fe2O4铁氧体纳米颗粒在光刻胶中均匀混合,再将该混合物涂覆在螺旋电感线圈上,实现电感性能的提升.这种新型低温工艺避免了常规制作铁氧体器件方法带来的高温处理(>600℃)对集成电路的破坏.与无磁膜覆盖样品对比,铁氧体覆盖电感的电感量在0.1～4 GHz提升了14～27%.这是实现高性能、全兼容铁氧体集成片上RF IC电感的一种很有前景的途径.     

Diffusional mobility for fcc phase of Al–Mg–Zn system and its applications

Diffusional mobility for fcc phase of the Al–Mg and Al–Mg–Zn systems was critically assessed by using the DICTRA software (Diffusion Controlled Transformation). Good agreement was obtained from comprehensive comparisons between the calculated and experimental diffusion coefficients. The developed mobility database enables reasonable prediction of diffusion and solidification behaviours resulting from interdiffusion, such as concentration profile of diffusion couples and solidification curve of the Al–Mg alloys.     

Numbering-up Y–Y microfluidic chips for higher-throughput solvent extraction of platinum(IV) chloride

The application of microfluidic devices to industrial processing is relatively scarce due to the high volumetric throughputs that are generally required. One approach to increasing throughput is massive parallelisation (‘numbering-up’ or ‘scale-out’), which involves the use of many microfluidic devices working in parallel to multiply the overall throughput. Numbering-up is attractive because it is modular and eliminates traditional ‘scale-up’ stages on the path towards full-scale processing. However, numbering-up presents other challenges, some of which are addressed here for liquid–liquid extraction using Y–Y chips. The theoretical limits were explored using the extraction of hexachloroplatinate(IV) ions as an industry-relevant system (extraction using a secondary amine). Experimental numbering-up from one channel to five, and then ten, in an extraction module is demonstrated, with extraction performance unchanged with increasing throughput. Calculations suggest that further numbering-up to at least a 1000-channel module could be facilitated by minor modifications to the present circuit.     

High-speed and precise positioning of an X–Y table

Positioning plays an important role in manufacturing machines. This work presents a novel two-step controller strategy to achieve fast and precise positioning at the same time on an X–Y table that moves across the macro-dynamic range and settles to within the micro-dynamic resolution. The model dynamics in the macro- and the micro-region are both discussed and the controller design is separated into two parts to satisfy the requirements in each region. The switching condition of the controller is well defined. Experimental results indicate that the proposed two-step controller can move the system from the macro-region into the micro-region in 0.2 s with an accuracy of 1 μm.     

Modelling the thermodynamic data for hcp Zn and Cu–Zn alloys– an ab initio and calphad approach

The phase diagrams of systems between zinc and elements such as Cu, Ag and Au show two distinct hcp phases on the Zn side of the system. Because of this, it is difficult to model the thermodynamic properties of these phases within a single dataset. As a result it is common to assess the data for these systems with two hexagonal phases, a phase HCP_A3 with a near ideal c/a ratio and the terminal solid solution of Zn with an anomalously high value for this ratio designated as HCP_ZN. We have examined the effect of additions of Cu on the enthalpy of mixing and lattice parameters of HCP_ZN in order to verify, using ab initio calculations, the origin of the above mentioned thermodynamic model for the alloy. The analysis of the calculations allows us to suggest a possible alternative to the state-of-the-art two hcp phases approach akin to the magnetic model used with success within the CALPHAD modelling.     

Re-assessment of the Mg–Zn–Ce system focusing on the phase equilibria in Mg-rich corner

The Mg–Zn–Ce alloys exhibit good creep resistance and strength at elevated temperature due to the formation of intermetallic compounds. However, the ternary compounds and phase equilibria in the Mg-rich corner are still controversial which restrains the development of Mg–Zn–Ce alloys. The present work experimentally investigated the phase equilibria in Mg-rich corner of the Mg–Zn–Ce system at 350 and 465 °C and thermodynamically assessed the Mg–Zn–Ce system. The existence of ternary compounds τ₁ and τ₃ were confirmed by a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystal structure of τ₁ was resolved as space group of Cmc21 with a = 0.9852(2)–1.0137(2) nm, b = 1.1361(3)–1.1635(3) nm and c = 0.9651(2)–0.9989(2) nm by Rietveld refinement of the XRD pattern. Three invariant reactions, L→τ₃+CeMg₃+CeMg₁₂, L+CeMg₁₂→α-Mg+τ₁ and L+τ₁→τ₂+α-Mg, were revealed by differential scanning calorimeter (DSC) measurement and microstructure characterization. Then, a set of self-consistent thermodynamic parameters was thereafter constructed by assessing the phase equilibria, solid solubilities of CeMg₁₂, τ₁, CeMg₃ and τ₃, as well as the formation enthalpies of binary and ternary compounds calculated by density functional theory. The comparison of calculated phase diagram with experimental results and the literature were discussed. The calculated isothermal section of Mg–Zn–Ce system at 465 °C agreed with our experimental data. The two three-phase equilibria, τ₁+α-Mg+CeMg₁₂ and CeMg₃+τ₃+CeMg₁₂, were confirmed in the Mg-rich corner. This thermodynamic database can be used for the further alloys design of Mg–Zn–Ce system.