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W360 is a hot work tool steel produced by voestalpine BÖHLER Edelstahl GmbH & Co KG, a special steel producer located in Styria, Austria. Surface tension and density of liquid W360 were studied as a function of temperature in a non-contact, containerless fashion using the oscillating drop method inside an electromagnetic levitation setup. For both, surface tension and density, a linear model was adapted to present the temperature dependence of these measures, including values for the uncertainties of the fit parameters found. The data obtained are compared to pure iron (with 91 wt% the main component of W360), showing an overlap for the liquid density while there is a significant difference in surface tension (− 5.8 % at the melting temperature of pure iron of 1811 K).

On the basis of the lattice potential energy with two forms proposed by Born–Mie and Born–Mayer, respectively, the critical interionic separations $${{ r}}_{\mathrm{i}}$$ where the lattice is fractured due to tensile force have been evaluated for alkali metal halides. The theoretical results are analyzed together with the interionic separations $${{ r}}_{\mathrm{m}}$$ determined by the melting temperature and the help of the isobaric equation of state. A new and simple interrelationship between $${{ r}}_{\mathrm{m}}$$ and $${{ r}}_{\mathrm{i}}$$ is obtained, and the crystal melting behavior can be accordingly predicted for NaCl-structure ionic crystals.

A series of high-temperature fixed points (HTFPs) Pt–C (1738 $$^{\circ }\mathrm {C}), \text {Cr}_{7}\text {C}_{3}{-\text {Cr}}_{3}\text {C}_{2}\,(1742\,^{\circ } \mathrm{C}), \text {Cr}_{3}\text {C}_{2}{-\text {C}}\,(1826\,^{\circ }\mathrm{C})$$ , and Ru-C (1953 $$^{\circ }\text {C}$$ ) have been constructed at the National Physical Laboratory (NPL) and the Laboratoire National de metrologie et d’Essais and Conservatoire national des arts et metiers (LNE-Cnam). These are required for the calibration of high-temperature thermocouples in the framework of work package 6 of the European Metrology Research Programme IND01 project “HiTeMS.” The goal of this work package is to establish a European capability that can determine low-uncertainty reference functions of non-standard high-temperature thermocouples. For reference functions to be widely applicable, measurements must be performed by more than one institute and preferably by more than one method. Due to the high price of the ingot materials, miniature HTFP cells are used. NPL and LNE-Cnam constructed their HTFP cells with different designs; these are described here, together with the performance of the cells using both radiation thermometry and thermocouples. The melting temperature of the Ru–C cells (for thermocouple calibrations) was determined using radiation thermometry at both NPL and LNE-Cnam, and the two results are compared. The suitability of the cells for calibration of W–Re and Rh–Ir thermocouples is evaluated, and some results are presented. Some discussion is given regarding the materials challenges when calibrating Rh–Ir thermocouples up to 2000 $$^{\circ }$$ C.

A semi-empirical relation to compute the pressure dependence of the melting temperature, $$T_\mathrm{m}(P)$$ , is derived in terms of the bulk modulus, Gruneisen parameter, and their first derivative with pressure. It is used to compute $$T_\mathrm{m}(P)$$ for iron for pressures ranging up to 350 GPa at conditions relevant to the Earth’s core. The computed results are in excellent agreement with the values obtained from first principle calculations.

Lindamann’s formula is extended to investigate the pressure dependence of the melting temperature, Tm(P). The important ingredient is the pressure dependence of the Debye temperature which has been determined from the measured data of acoustic longitudinal and transverse waves velocities. It is shown that Lindemann’s type relation can be utilized to obtain an empirical relation for Tm(P) in terms of the Gruneisen parameter and the bulk modulus. Computed values of Tm(P) for alumina, Heusler alloy, and gabbro (an igneous rock) are presented.

For high-temperature fixed points to be accepted as temperature refer- ences, it is of prime importance that their long-term stability is demonstrated. This evaluation is part of the CCT-WG5 high-temperature research project (Machin et al. in Int. J. Thermophys. 28, 1976, 2007) devoted to a comprehensive evaluation of three high-temperature fixed points: Co-C (1324 ◦ C), Pt-C (1738 ◦ C), and Re-C (2474 ◦ C). The assessment of the long-term stability, as well as the robustness of the cells, is exam- ined in the first workpackage of this project. Four cells for each of the eutectic points have been constructed by NMIJ (4 Co-C, 2 Pt-C, and 4 Re-C) and NPL (2 Pt-C), and stability tests have subsequently been performed by NMIJ (Co-C), NIM (Pt-C), and VNIIOFI (Re-C). These tests consisted of ageing one cell among the set of four, for a period of 50 h around the melting temperature. For each of the three eutectic points

By using the embedded-atom method (EAM), a series of molecular dynamics (MD) simulations are carried out to calculate the viscosity and self-diffusion coefficient of liquid copper from the normal to the undercooled states. The simulated results are in reasonable agreement with the experimental values available above the melting temperature that is also predicted from a solid–liquid–solid sandwich structure. The relationship between the viscosity and the self-diffusion coefficient is evaluated. It is found that the Stokes–Einstein and Sutherland–Einstein relations qualitatively describe this relationship within the simulation temperature range. However, the predicted constant from MD simulation is close to 1/(3π), which is larger than the constants of the Stokes–Einstein and Sutherland–Einstein relations.

A new high-temperature furnace was developed in VNIIM and manufactured by the Omsk plant “Etalon.” This furnace is intended for the realization of various fixed points of pure metals and high-temperature metal–carbon eutectics up to a temperature of 3000°C. The construction of the furnace allows measurements to be carried out either with or without the protective window, in a protective atmosphere of argon. The furnace will be described in this article. Cooperation with LNE-INM was initiated with the aim of sharing experience in metal–carbon eutectic cell construction and comparing two Pt–C cells (one cell was made by each partner) as a means of comparing scale realizations around 1740°C. The filling technique used in each laboratory will be described. The average melting temperature of the VNIIM Pt–C eutectic cell, characterized and studied at VNIIM, was 1738.4°C with a standard uncertainty of about 0.13 K. The repeatability of the melting temperature with various measurements was estimated to be within the limits of (0.02–0.2) K. The cell supplied by LNE-INM is the one that was constructed and studied in the framework of the HIMERT European project and described elsewhere. The difference in the melting temperatures of the fixed points (VNIIM—LNE-INM) is about 0.4 K with a standard uncertainty not exceeding 0.18 K. The cells constructed and characterized by each partner were exchanged and measured by the other partner. The results of the study of the melting and freezing of the Pt–C cells carried out by VNIIM and LNE-INM will be presented. The reasons for the difference in the melting temperatures of the two cells are analyzed, and the steps preceding the comparison of the scale realizations of the two laboratories are presented.

The objective of the EUROMET Project 857 in the field of thermometry, “High-temperature fixed points for improved thermocouple calibrations,” is the development of robust high-temperature fixed points based on metal-carbon eutectic alloys for the calibration of thermocouples above 1,084°C. This paper describes the construction and investigation of Pt/Pd thermocouples to be used to compare different cobalt–carbon (Co–C) fixed-point cells constructed by the three participants of this project. A set of three Pt/Pd thermocouples was prepared by PTB and NPL and a set of four by LNE. Their metrological performances in terms of thermoelectric stability and homogeneity were assessed in different ways. The results of these investigations, as well as the results of first measurements of local Co–C eutectic fixed-point cells by using Pt/Pd thermocouples, are presented.

A novel fixed-point cell design that allows simultaneous measurements using contact and non-contact thermometers was developed and investigated at PTB to realize the nickel-carbon (Ni–C) fixed-point. The melting temperature indicated by the LP3 radiation thermometer amounted to (1328.86 ± 0.52)°C (k = 2). The melting temperature of the Ni–C fixed-point cell was also calculated by extrapolating the emf-temperature characteristics of two Pt/Pd thermocouples based on their calibrations at conventional fixed points of the ITS-90. The melting temperature of the Ni–C eutectic amounts to (1328.44 ± 0.45)°C using thermocouple Pt/Pd 01/04, and to (1328.53 ± 0.46)°C using thermocouple Pt/Pd 01/05, with uncertainties for k = 2. The contact and non-contact thermometers agree well within the combined uncertainties.

Experimental improvements of a four-probe technique to measure the electrical resistivity of molten metals led to an improvement of the measurement uncertainty to less than 6%. Measurements of pure Al and AlSi-, AlSiMg-, and AlSiCu-alloys with a systematic variation of individual components are described. The problem of the calculation of the thermal conductivity has been investigated, and the resulting values of the binary system have been discussed in terms of behavior during melting and solidification. There is a remarkable difference of the thermal conductivity before melting and after resolidification.

Molecular dynamics simulations (MDS) employing an embedded-atom-method (EAM) are applied to calculate the density and specific heat of liquid Ti–Al alloys at temperatures above and below the melting temperature in a wide composition range. Both the temperature and composition dependences of these two properties are investigated. The excess volume of Ti–Al alloys is calculated from the predicted density, and shows a negative value. The specific heat of liquid Ti–Al alloys increases linearly with a decrease of temperature. Unlike the monotonic change of density with the addition of aluminum, the specific heat reaches its maximum value at the composition of Ti–50at%Al alloy. Thus, both the density and specific heat show highly nonideal behaviors, indicating that Neumann–Kopp’s rule does not apply.

The heat capacity of e-H 2 with powder of FeO(OH) used as a catalyst for ortho-para equilibration has been investigated using sealed cells fabricated at the National Institute of Standards and Technology and at the National Metrology Institute of Japan. An anomalous double peak has been observed in their heat capacities at temperatures just below the triple point independent of sources of H2 and FeO(OH) and designs of sealed cells. Supercooling behavior has been observed not only at the triple point but also at each anomalous peak resulting from a depression of the melting temperature of a portion of solid H 2 in close physical proximity to the catalyst. The reduction of the amount of catalyst suppresses the size of the anomalies and allows one to obtain more reliable melting curves for e-H2 at the triple point.

The acoustical impedance of liquid sulfur has been measured for the first time for both longitudinal and shear sound waves over the frequency range from 5 to 25 MHz from the melting temperature to 180 °C. The experiment shows that sulfur is not a viscoelastic liquid either below or above the polymerization transition temperature.

In this paper, a molecular dynamics simulation based on the embedded-atom method (EAM) is applied to calculate the specific heat capacity of the Fe-33% Ni alloy at temperatures above and below the melting temperature. The relationship between the specific heat of the alloy and undercooling is investigated. The heat capacity of the Fe-Ni alloy is a constant in the superheated and undercooled liquid states. Comparisons between previous work and the current study show that the heat capacity behavior of undercooled alloy strongly depends on the species of the alloy.

The melting temperature of 99.98+ % pure nickel was measured by means of a subsecond duration pulse heating technique. The results, based on IPTS-68, yield a value of 1729 K for the melting temperature with an estimated maximum uncertainty of ±4 K.

Simultaneous measurements of the specific heat capacity, c p, electrical resistivity, ρ, and hemispherical total emittance, e, of tungsten-3 (wt%) rhenium alloy in the temperature range 1500–3600 K by a subsecond-duration pulse heating technique are described. The results are expressed by the relations $$\begin{gathered} c_{\text{P}} = 0.30332 - 2.8727 \times 10^{ - 4} {\text{ }}T + 1.9783 \times 10^{ - 7} {\text{ }}T^2 \hfill \\ {\text{ }} - 5.6672 \times 10^{ - 11} {\text{ }}T^3 + 6.5628 \times 10^{ - 15} {\text{ }}T^4 , \hfill \\ \rho = - 24.261 + 8.1924 \times 10^{ - 2} {\text{ }}T - 3.7656 \times 10^{ - 5} {\text{ }}T^2 \hfill \\ {\text{ + 1}}{\text{.1850}} \times {\text{10}}^{ - 8} {\text{ }}T^3 - 1.3229 \times 10^{ - 12} {\text{ }}T^4 , \hfill \\ \varepsilon = 0.1945 + 5.881 \times 10^{ - 5} {\text{ }}T, \hfill \\ \end{gathered} $$ where T is in K, cp is in J·g−1·K−1, and ρ is in μΩ·cm. The melting temperature (solidus temperature) was also measured and was determined to be 3645 K. Uncertainties of the measured properties are estimated to be not more than ±3 % for specific heat capacity, ±1 % for electrical resistivity, ± 5 % for hemispherical total emittance, and ±20 K for the melting temperature.