Donatella Giuranno

• Ph.D Chemical Engineer
• Institute of Condensed Matter Chemistry and Technologies for Energy, Italian National Research Council

The viscosity of Ni-Al and Ni-based multicomponent alloys has been investigated from the experimental and theoretical points of view.

The aim of this review is to succinctly review recent progress in experimental and theoretical investigation of the viscosity of binary and multicomponent Ni–Al-based industrial alloys, summarising the current state of knowledge of the topic. Viscosity data are important for simulation of microstructural evolution during solidification-related proc...

Surface tension and viscosity of complex Ti-based industrial alloys are important for simulation of liquid assisted industrial processes such as casting, joining, crystal growth and infiltration. Modelling of the interface and mass transport during liquid-solid phase transition requires reliable surface tension and viscosity data. Therefore, to obt...

Surface tension and viscosity of complex Ti-based industrial alloys are important for simulation of liquid assisted industrial processes such as casting, joining, crystal growth and infiltration. Modelling of the interface and mass transport during liquid-solid phase transition requires reliable surface tension and viscosity data. Therefore, to obt...

Research activities in materials science typically range from basic and curiosity-motivated research to that which is applications-oriented, and the well-known Materials Science paradigm is usually followed: Processing → Microstructure → Properties → Performance [...]

Boron-doped molybdenum silicides have been already recognized as attractive candidates for space and ground ultra-high-temperature applications far beyond limits of state-of-the-art nickel-based superalloys. In this work, we are exploring a new method for fabricating Mo–Si–B alloys (as coatings or small bulk components) by utilizing a pressure-less...

Simulation of casting and joining processes and experimental planning are closely related to liquid metallic materials thermophysical properties. Thermophysical properties datasets of Ni-based industrial alloys were analyzed through the application of experimental methods and theoretical models. The use of two or more models is useful for the const...

Among thermophysical properties, the surface/interfacial tension, viscosity, and density/molar volume of liquid alloys are the key properties for the modelling of microstructural evolution during solidification. Therefore, only reliable input data can yield accurate predictions preventing the error propagation in numerical simulations of solidifica...

Among the thermophysical properties, the surface / interfacial tension, viscosity and density / molar volume of liquid alloys are the key properties for the modelling of microstructural evolution during solidification. Therefore, only reliable input data can yield accurate predictions preventing the error propagation in numerical simulations of sol...

Simulation of casting and joining processes and experimental planning are closely related to liquid metallic materials’ thermophysical properties. Thermophysical properties datasets of Ni-based industrial alloys were analyzed through the application of experimental methods and theoretical models. The use of two or more models is useful for the cons...

Mg-based alloys are potential candidate materials for a fabrication of lightweight boron carbide based composites through a reactive melt infiltration approach. In this paper, the effect of a mechanical purification of molten AZ91 alloy's surface on its wettability with polycrystalline B4C is experimentally evaluated for the first time. For this pu...

The design of processing routes involving the presence of the liquid phase is mainly associated with the knowledge of its surface and transport properties. Despite this need, due to experimental difficulties related to high temperature measurements of metallic melts, for many alloy systems neither thermodynamic nor thermophysical properties data ar...

The design of processing routes involving the presence of the liquid phase is mainly associated with the knowledge of its surface and transport properties. Despite this need, due to experimental difficulties related to high temperature measurements of metallic melts, for many alloy systems neither thermodynamic nor thermophysical properties data ar...

To properly design and optimize liquid-assisted processes, such as reactive infiltration for fabricating lightweight and corrosion resistant SiC/TiSi2 composites, the extensive knowledge about the interfacial phenomena taking place when liquid Si-rich Si-Ti alloys are in contact with glassy carbon (GC) is of primary importance. To this end, the wet...

To design properly and optimizate liquid-assisted processes such as reactive infiltration for fabricating light weight and corrosion resistant SiC/TiSi2 composites, the interfacial phenomena taking place when liquid Si-rich Si-Ti alloys are in contact with glassy carbon (GC) were investigated for the first time by wetting tests performed by both th...

Conventional high-chromium ferritic / martensitic steels, such as T91 and AISI 316 L as well as the new oxide dispersed strengthened (ODS) steels, i.e. Fe-Cr (ferritic or martensitic) with a fine Y2O3 dispersion, are promising candidates as structural materials for applications in aggressive environments. In order to improve the efficiency and life...

The present study is an overview of the surface properties of liquid Al-Ni alloys, which are of great importance for the design and development of new Al-Ni and Ni-based industrial alloys, widely used as functional and structural materials. The solidification and thus, the microstructural evolution are directly dependent on the interface / surface...

Among additive manufacturing (AM) processes, Selective Laser Melting (SLM) is the most diffused layer by layer method for manufacturing 3D components. It is based on local melting, induced by a laser scanning, on a powder bed; the limited dimensions of the liquid pool provoke rapid cooling rates which can be associated to significantly finer micros...

The surface tension of liquid Ag\ \Cu eutectic alloy has been measured in a wide range of oxygen partial pressures using two different methods: the constrained drop method and the electromagnetic levitation method. In order to investigate the influence of oxygen potential on the surface tension of the Ag\ \40Cu (at.%) eutectic alloy, the oxygen par...

The present study is aimed to deep the knowledge on the corrosion behavior of martensitic T91 steel in contact with liquid lead in view of its application in advanced nuclear energy systems. Steel’s samples have been analyzed after the immersion in stagnant molten lead at different temperatures (550-650°C) and for an exposure time of 550 h. In o...

Silicon-boron alloys have been recently pointed out as novel ultra-high temperature phase change materials for applications in Latent Heat Thermal Energy Storage (LHTES) and conversion systems. One of the emerging challenges related to the development of such devices is a selection of refractories applicable to build a vessel for storing molten Si-...

Currently, the main challenge facing the development of advanced MMCs and CMCs are related to the costly fabrication of tailored interface microstructures for highly demanding applications. In designing advanced refractory composites, reactive infiltration of liquid Si-enriched Si-Zr alloys into C- or SiC-based preforms may be a cost-less alternati...

Computational models are powerful tools for materials design. Since longer time, SiC-based composites gain interest for their potential use in aerospace, automotive, and other highly demanding applications. In particular, the production of tailored SiC-based composites via reactive infiltration of Si-based alloys into C- and SiC-based preforms, mai...

Light-weight materials capable of bearing load have become increasingly valuable for designing, construction and assembling of lightweight transportation systems such as aircraft, high-speed trains and satellites. To produce competitive advanced MMCs, SiC- and Cf/C-based composites with desirable properties, the reactive infiltration process has ad...

In this paper, new improvements of methodological concepts upon examining wettability of high vapor pressure liquid metal systems (e.g. Mg-based alloys) in contact with refractory materials, are presented and discussed. In this regard, high-temperature experiments on molten magnesium (Mg) in contact with graphite as a refractory substrate, were per...

The new Bi–Sn surface tension experimental data have been obtained by the pinned drop method for temperatures ranging from 623 to 1123 K and were subsequently compared with the model predicted values as well as with the literature data. Taking into account endothermic mixing in liquid Bi–Sn alloys, the surface properties (surface tension and surfac...

To succeed in the design and optimization of liquid-assisted processes such as reactive infiltration for the fabrication of tailored refractory SiC/ZrSi2 composites, the interfacial phenomena that occur when Si-rich Si-Zr alloys are in contact with glassy carbon (GC) were investigated for the first time by the sessile drop method at T = 1450 °C. Sp...

To design and optimize liquid-assisted processes such as reactive infiltration for fabricating refractory SiC/ZrSi2 composites, basic investigations on the interfacial phenomena occurring when liquid Si-based alloys are in contact with C and SiC substrates, are key steps. Indeed, targeted wettability studies may provide helpful indications for find...

Reactive melt infiltration of Si-based alloys into C preforms and SiC/C composites may be an affordable alternative route to fabricate highly performant light-weighting metal matrix (MMCs) and ceramic matrix (CMCs) composites, as well as to obtain reliable and long-term stable joints. In order to optimize reactive infiltration process and to tailo...

In designing advanced refractory composites for highly demanding applications, reactive infiltration of liquid Si-enriched Si-Zr alloys into C-or SiC-based preforms may be a viable cost-less manufacturing process. In such cases, in view to optimize liquid assisted processes such as reactive infiltration, a fundamental investigation on the interfaci...

SiC is a material with excellent mechanical and thermal properties but with a high production cost. Obtaining SiC by reactive infiltration is an attractive method with a much lower cost than the traditional sintering process. However, the reactive infiltration process presents a serious problem, which is the high residual silicon content, which dec...

Reactive infiltration of liquid Si-enriched alloys into C- or SiC-based preforms is a viable cost-less alternative to manufacture dense and highly performant SiC-based and MMC composites. In view to design and optimize liquid-assisted processes such as reactive infiltration, fundamental investigations on the interfacial phenomena occurring when the...

SiC is a material with excellent mechanical and thermal properties, but with a high production cost. Obtaining SiC by reactive infiltration is an attractive method and at a much lower cost than the traditional sintering process. However, the reactive infiltration process presents a serious problem, which is the high residual silicon content, which...

Currently, MMCs with SiC as reinforcement emerge as ideal candidates for long-term stable devices withstanding high temperatures and harsh operating environments which are typical for many industrial sectors, such as energy, aerospace, electronics, catalysis, etc. However, the costly manufacture of such composites is the major restraint to make the...

Goal: Aiming to ‘‘mimic’’ the conventional operating conditions imposed in fabricating MMCs via liquid processes such as reactive infiltration, the contact heating sessile drop method (CHSD) was applied for better understanding the interaction phenomena occurring between the liquid Si-10at%Zr alloy in contact with Glassy Carbon (GC) and SiC substra...

Goal: Different CMCs were successfully joined by Si Ti alloys via reactive infiltration process The joining process the interfacial phenomena observed and the developed microstructures were related to the Si content and process parameters. The Si Ti/C and Si Ti/ SiC resulting interfaces were carefully analyzed and the overall phenomena occurred wit...

Goal: Systematic investigations of the surface tension and density properties of Si Me eutectic alloys Me Co Ti Zr have been carried out by the pendant drop method in the temperature range of ( 20 ÷ 1550 C) Why?:Reliable thermophysical properties data of liquid metal systems are valuable inputs for computer simulation enabling optimization of sever...

Introduction/Purpose: SiC is one of the candidates for highly demanding applications because of its outstanding properties. Reactive infiltration of Si-based alloys into C and SiC-C preforms is a valuable costless alternative over other conventional processing techniques to produce SiC based and MMCs composites. It is even used to join CMCs for sha...

In order to investigate a protective coating approach for nuclear applications, two different aluminum rich layers were deposited on T91 steel coupons: Ti-Al-N films were grown via High Power Impulse Magnetron Sputtering and AlO coatings were produced by Radio Frequency Magnetron Sputtering. In this exploratory work, coated specimens were corrosion...

The contact heating sessile drop and capillary purification methods were applied for a fundamental study concerning the wettability and reactivity of liquid Si-16.2at%Ti alloy (eutectic composition) in contact with Glassy Carbon and SiC at T = 1450°C under an Ar atmosphere. Different spreading stages with different slopes, depending on the starting...

In this work, we used a sessile drop experiment to assess the feasibility of novel processing design engaging liquid-phase assisted fabrication of multi-phase materials from Mo-Si-B system. For this purpose, binary eutectic silicon-boron alloy (Si-3.2B wt%) was subjected to contact heating with polycrystalline molybdenum substrate at temperature up...

The contact heating sessile drop method was applied for a fundamental study concerning the wettability and reactivity of liquid Si-16.2 at.%Ti (eutectic composition) in contact with glassy carbon. The evolution of the contact angle behaviors and spreading kinetics were evaluated at three different temperatures. A strong temperature dependence was f...

Reactivity between SiC and Ir as a function of SiC-crystallinity was investigated by diffusion bonding technique under a vacuum and over the temperature range of 1200–1450 °C. As reaction products, various Ir-silicides and free unreacted-C were detected. Reactivity is strongly affected by the temperature and SiC-crystallinity involving a series of...

Scientific research and innovation are among the most powerful forces driving economic development and social change. Yet while scientific research facilities become larger, more complex, and require more resources, funding trend for scientific research is often not increasing in many countries even as the timescale for projects. Facing with such “...

The ESA-MAP* THERMOPROP project aims to measure and analyze the thermophysical properties of liquid metal alloys over a range of high temperatures.The ThermoProp International team has the opportunity to perform measurements on the International Space Station (ISS) optimally sharing the use of the Electro Magnetic Levitation (EML) facility. In para...

Highly-dense, nearly net-shaped SiC/TiSi2 composites (Fig. 1) effortless produced by reactive infiltration of liquid Si-16.2at%Ti eutectic alloy into bimodal SiCp-C porous preforms under an atmosphere, are presented. Such composites might be promising candidates as light-weight advanced materials for construction and assembling of lightweight trans...

Silicon has recently been recognized as a potentially attractive phase change material for ultra-high-temperature latent heat thermal energy storage (LHTES) and conversion systems. It has been proposed that the utilization of silicon’s latent heat should drastically increase the performance of LHTES devices in terms of operational temperatures and...

In this work, the effect of boron content on the high-temperature wetting behavior in the Si-B alloy/h-BN systems was experimentally examined. For this reason, hypoeutectic, eutectic and hypereutectic Si-B alloys (Si-1B, Si-3.2B and Si-5.7B wt.%, respectively) were produced by electric arc melting method and then subjected to sessile drop/contact h...

The present work is aimed to highlight the interfacial properties (surface tension and wettability) of metallic systems involved in the additive manufacturing processing (AM) and their importance for design and development of new candidate materials as it has been already done in the field of joining processes (soldering, brazing, welding). The sur...

Silicon has been recently proposed as a very promising phase change material for applications in latent heat thermal energy storage (LHTES) and conversion systems working at ultra-high temperatures. However, in order to successfully develop such kind of devices, suitable refractories showing low reactivity and non-wetting behavior upon the melting...

In this paper, the experimental performance of a new testing device designed for investigating the high temperature properties of molten Mg is presented. The newly developed device allows examining high temperature wetting behavior and thermophysical properties of molten Mg (and Mg alloys) by using various experimental procedures (e.g. classical se...

Wettability between liquid Ag and graphene-coated SiC single crystal has been investigated by dispensed drop method at T = 970 °C under vacuum accompanied with subsecond recording of the drop/substrate images (100 frames per second) by high-speed high-resolution CCD camera. Non-contact heating method coupled with capillary purification of the Ag dr...

Integration of graphene into electronic circuits through its joining with conventional metal electrodes (i.e. gold) appears to be one of the main technological challenges nowadays. To gain insight into this junction, we have studied the physicochemical interactions between SiC-supported graphene and a drop of molten gold. Using appropriate high tem...

Viscosity of liquid Ag-Cu alloys is determined over the entire compositional range as function of temperature and composition by means of the oscillating cup technique. It is found that the viscosities of the pure elements can be related to their self-diffusion coefficients via the Stokes-Einstein relation. The isothermal viscosities of the alloys...

Viscosity of liquid Ag-Cu alloys is determined over the entire compositional range as function of temperature and composition by means of the oscillating cup technique. It is found that the viscosities of the pure elements can be related to their self-diffusion coeffcients via the StokesEinstein relation. The isothermal viscosities of the alloys in...

Particle stabilized liquid foams are used as templates to obtain carbon-based porous materials with open cell structure, high specific area and hierarchical porosity. This route relies on gel casting to strengthen the structure of the liquid foams, followed by high temperature treatment to eliminate organic components and obtain solid foams. The li...

The knowledge of thermophysical properties of liquid Co-Si alloys is a key requirement for manufacturing of composite materials by infiltration method. Despite this need, the experimental and predicted property data of the Co-Si system are scarce and often inconsistent between the various sources. In the present work the mixing behaviour of Co-Si m...

The thermophysical properties, e.g., melting range, specific heat, solid fraction, density, and surface tension of four industrial Ni-based alloys, namely MC-2, CMSX-10, TMS-75, and LEK-94, have been determined within the ground-based experiments program of the ESA MAP ThermoProp project. The tests were performed under reducing atmosphere in order...

Among manufacture techniques for SiC ceramics, reactive infiltration has proven to be the most efficient. However, materials manufactured with this technique present minimum 10% of unreacted silicon. Si hinders the performance of the material. The replacement of Si with a MexSiy can improve the performance of the composite. Since Me–Si alloys wet c...

The surface tension and density of Ni-based superalloys RENE N5® and RENE 90® have been measured by the pinned drop method at temperatures ranging from 1638 to 1780 K. In order to obtain accurate reliable data, the tests have been performed under a reducing atmosphere to minimize the oxygen contamination. In the temperature ranges investigated, bot...

Surface tension of liquid Ag–Cu binary alloys has been measured contactlessly using the technique of electromagnetic levitation in combination with the oscillating drop technique. The measurements were performed at temperatures above the melting point of alloys. The surface tension values were obtained from an analysis of the frequency spectra of d...

Experimental determination of thermodynamic and thermophysical properties of both solid and, in particular, liquid alloys at high temperatures is often technically difficult or even impossible, and therefore theoretical models can be used to estimate missing property values. Preliminary inspection of the literature related to the Cr-Nb-Re system an...

In this work, the surface tension and density of Si-Ge liquid alloys were determined by the pendant drop method. Over the range of measurements, both properties show a linear temperature dependence and a nonlinear concentration dependence. Indeed, the density decreases with increasing silicon content exhibiting positive deviation from ideality, whi...

Experimental determination of thermodynamic and thermophysical properties of both solid and, in particular, liquid alloys at high temperatures is often technically difficult or even impossible, and therefore theoretical models can be used to estimate missing property values. Preliminary inspection of the literature related to the Cr-Nb-Re system an...

Surface tension of liquid Ag–Cu binary alloys has been measured contactlessly using the technique of electromagnetic levitation in combination with the oscillating drop technique. The measurements were performed at temperatures above the melting point of alloys. The surface tension values were obtained from an analysis of the frequency spectra of d...

A new testing procedure combining in one test two methods for surface tension measurements of liquid metals [the pendant drop (PD) and the sessile drop] and carried out in the same device is discussed. The attention is focused on methodological aspects of the PD method due to the novelty of its application for high temperature metallic systems. It...

In the present work, the surface tension of liquid Si and Ge has been measured by the pendant/sessile drop combined method over the temperature range of 1723–1908 K and 1233–1313 K, respectively. The new surface tension data, the molar volumes and the melting temperatures of silicon and germanium as well as the excess Gibbs energy data of the Ge–Si...

Low melting Au based alloys offer an interesting combination of high corrosion and creep resistance as well as good electrical and thermal conductivity, and they support the capability for fluxless soldering. Despite their high price, Au alloys are of special interest for high temperature solder applications where these characteristics are essentia...

The analysis of the oxygen–liquid metal interaction is a topic of particular technological interest. A deep knowledge of the kinetics and transport mechanisms involved in the oxidation phenomena is necessary: the effect of oxidation reactions taking place in the gas phase and the evaporation of oxides must be considered.This paper aims to review ou...

Au-Ge-based alloys are interesting as novel high-temperature lead-free solders because of their low melting point, good thermal and electrical conductivity, and high corrosion resistance. In the present work, the wetting and soldering behavior of the eutectic Au-28Ge (at.%) alloy on Cu and Ni substrates have been investigated. Good wetting on both...

In this work a double contribution to the characterization of molten In and In-Sn alloys considered as main components of an important class of lead free solder materials is shown: the study of the influence of oxygen on the capillary phenomena and the XRD investigation of the structure of liquid in a range of temperatures around that of liquidus....

The mixing behaviour of liquid Sb–Sn alloys has been described in terms of energetics and structure through the study of their thermodynamic, surface, transport and structural properties by using the Complex Formation Model (CFM) in the weak interaction approximation and by postulating SbSn chemical complexes as energetically favoured. The new Sb–S...

The evaluation of oxygen-liquid metal interactions is a topic of undoubted interest for different technological processes such as optimizing the preparation of binary alloys. In such instances, productive processes can be more easily studied using theoretical approaches based on the study of mass-transport phenomena in liquid metal-gas systems. The...

A new combined method using two methodologies in one test (i.e. the pendant drop and sessile drop) by an advanced experimental complex that has been designed for investigations of high temperature capillarity phenomena, is presented. The surface tension data obtained by the application of a such new procedure on pure metals are presented here and d...

In the present work, the surface tension and density of a set of Al−Ni alloys have been investigated as a function of composition and temperature. The measurements were performed by the large drop method, under equilibrium and with an oxygen-free surrounding atmosphere to prevent oxidation phenomena. The study was focused mainly on Al-rich alloys i...

Within the Integrated Project IMPRESS, funded by the EU, a concerted action was taken to determine the thermophysical properties of a c-TiAl-based alloys, suitable for casting of large turbine blades for aeroengines and stationary gas turbines. The challenge was to develop a castable alloy, free of grain refiners and susceptible to heat treatment....

Surface phase transitions at Ga-rich liquid surfaces have been investigated in Ga–Pb alloys with low lead content. In the region of the liquid–liquid miscibility gap, the Pb-rich liquid phase completely wets the surface of the Ga-rich phase at coexistence. Observations have been made of demixing and solidification of the Pb-rich liquid film. Ga-ric...

The surface tension of the Cu−Sn system has been measured over the whole composition range by using the large drop method over the temperature range T = (430 to 1300) K. The measurements were carried out at equilibrium and under “oxygen-free” conditions. The results obtained were compared with the available literature data as well as with theoretic...

The mixing behaviour of liquid Bi–In alloys has been described in terms of energetics and structure through the study of their thermodynamic, surface and structural properties by using the Complex Formation Model (CFM) in the weak interaction approximation and by postulating BiIn-chemical complexes as energetically favoured. The new Bi, In and Bi–I...

The thermophysical properties of Cu-based industrial alloys in the liquid phase have been determined in the framework of ThermoLab project. Four commercial copper alloys provided by one member of the industrial user group, Cu-Sn-X (X = P; Ti), Cu-Ni-Si and Cu-Ni-Si-Mg have been investigated by different European laboratories. The results of the gro...

Dynamic surface-tension measurements using the sessile drop method and acquisition times of a few seconds make it possible to study the evolution of the surface of molten metals and alloys and so reliably validate the predictive models of the interactions between pure liquid metals and an oxidizing atmosphere, in both an inert gas carrier and in a...

The thermodynamic properties of liquid In–Sn alloys indicate a weak interactions between unlike atoms. The new In, Sn and In–Sn surface tension experimental data set obtained by the large-drop method over the temperature range 523–923 K together with the literature data on different thermophysical properties substantiate a nearly ideal mixing behav...

A theoretical model on oxygen transport at the surface of liquid metals has been validated by dynamic surface tension measurements performed on liquid Indium as test metal. The oxygen contamination conditions have been obtained at different oxygen partial pressures under both low total pressure (Knudsen regime) and inert atmospheric pressure (Fick...

The surface tension, density, and viscosity of the Ni-based superalloy CMSX-4® have been determined in the temperature ranges of 1,650–1,850K, 1,650–1,950K, and 1,623–1,800K, respectively. Each property has been measured in parallel by different techniques at different participating laboratories, and the results are compared with the aim to improve...

The main objective of this work is to determine the wetting behaviour of lead-free solders on copper substrates in view of their applications in electronic industry. The wetting behaviour of X–In–Sn (X=Au, Bi) ternary molten alloys in contact with copper has been studied and compared with the corresponding behaviour of their binary subsystems with...

This paper presents a detailed interpretation of the interface saturation data of liquid tin and aluminium drops, on the basis of a mathematical description of the interface evolution described in a previous paper. We also discuss the relevance of evolution times towards the stationary condition for both metal drops, which have given us a better un...

Dynamic surface tension measurements of molten aluminium have been carried out under different monitored oxygen partial pressures in the temperature range 873–1323 K with the aim of experimentally confirming the behaviour of molten metals in the presence of traces of oxygen as predicted by theoretical models [Ratto M, Ricci E, Arato E, Costa P. Met...