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The selective laser sintering (SLS) of an yttria (Y2O3) ceramic powder was studied to understand both the effects of i) the initial yttria particle characteristics on the powder bed behaviour and ii) the process conditions (laser power, scanning speed, hatching space) on the sintering/melting of three-dimensionally printed objects. The roughness of the powder bed, a sensitive indicator of the layer bed quality, was determined through three-dimensional optical profilometry and the powder bed packing density was modelled using the discrete-element method. Complex shaped objects including spheres and open rings were successfully fabricated by the SLS three-dimensional printing. In addition, SLS cube-shaped samples were characterized by X-ray diffraction and scanning electron microscopy. The open pore volume fraction significantly decreased from 41% without a post-SLS heat treatment to 31% with a post-SLS heat treatment at 1750 °C for 20 h under secondary vacuum. Finally, an anisotropy in elastic properties has been highlighted, Young's modulus reaches 11 GPa in the stiffest direction.

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In order to investigate drying mechanisms at different stages, the distribution of water within the ceramic green bodies at different scales has been examined. The experimental measurements, using a simple weighing technique and Magnetic Resonance Imaging (MRI), show that during the first stage of drying involving shrinkage the material is constituted of uniquely solid and water with no gradient in water content within the sample. Then, during the second stage of drying, significant differences of water content as a function of position appear. As a complement, at the grain scale, observations using environmental scanning electron microscopy were made giving useful information on the solid–liquid–gas interfaces in the near surface part of the green body. Finally, the gradients in the water distribution were exploited to make a simple estimate of the diffusion coefficient of water with its dependence on the moisture content.

Open ceramics 6, 100118 (2021). doi:10.1016/j.oceram.2021.100118 special issue: "Young Ceramists in the Spotlight / Edited ba Maria Canillas Perez, Erkka Frankberg, Andraž Kocijan, Marie Lasgordeix, Antonia Ressler, Laura Tiainen", Published by Elsevier, Amsterdam

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The evolution of shrinkage and mass during drying of kaolin and alumina green bodies was characterized. Standard practise uses a position sensor with simultaneous mass measurement. In this work an optical method was developed to follow shrinkage in two orthogonal directions. Green body samples were made by pressing of ceramic pastes. Results have been compared through the well known Bigot curves which show two distinct stages. First a linear shrinkage with the evaporated water loss is observed. Then in the second stage with further water loss, negligible dimension changes occur. For each material, the overall shrinkage values are identical in the two directions parallel to the pressing axis, but higher in the pressing direction. This difference is related to the shaping method yielding a preferential orientation of grains. Anisotropy in shrinkage is more significant for kaolin with tabular shaped grains compared to the more isometric grains of alumina.

This work investigates how silica and lignocellulose additives affect the production of metakaolin based-geopolymer foam filters. Lignocellulosic material from wood powder sawdust (S), silica from rice husk ash (RHA), calcined (Sa) and uncalcined (Sab) sand were separately used together with high amorphous silica fume (foaming agent) and integrated into the matrix (metakaolin and solution). The different geopolymer pastes were cured at 70 °C to enhance the pore formation. Results presented the geopolymer foams filter as sponge-like composites having 58–68% of porosity with 1–4 MPa of compressive strength. RHA and Sa lead to materials with more meso and macropores. Sawdust based-geopolymer (the hardest foam) containing channel pores predominated by coarse pores exhibited a flow rate of 4 mL min−1. The absence of the bands of MB from FT-IR spectra and UV spectra (663 nm) of MB filtrate (totally blue discoloured) indicated that, geopolymers foams filters designed are suitable for dyes and wastewater filtration.

This study focuses on the preparation of porous poly(phospho-siloxo) networks for thermal insulation applications using commercial calcium carbonate and calcium-rich wastes such as oyster shell, snail shell and eggshell powders as pore-forming agents. The control and porous poly(phospho-siloxo) networks were prepared by adding phosphoric acid (4 M) as a chemical ingredient to metakaolin containing 0 and 15 wt% of each foaming agents. The final products were monitored using the X-ray diffractometry, infrared spectroscopy, apparent density, absolute density, thermal conductivity, optical microscopy, scanning electron microscopy and mercury intrusion porosimetry. The results show that the thermal conductivity of the control and porous poly(phospho-siloxo) network from commercial calcium carbonate are 0.35 and 0.20 W/mK, respectively. They were higher compared to those from snail shell (0.17 W/mK), eggshell (0.15 W/mK) and oyster shell (0.14 W/mK). The cumulative pore volumes are 211.4, 365.5, 380.6, 389.7 and 393.3 mm3/g for the control and porous specimens from chicken eggshell, commercial calcium carbonate, snail shell and oyster shell powders, respectively. Their total porosity measured by mercury intrusion porosimeter are 30.9, 45.5, 46.0, 45.9 and 45.4%, respectively, whereas those calculated with apparent and true density measured by pycnometer are 34.48, 45.25, 52.74, 50.84 and 52.60%, respectively. The concentrated pore size diameter of the porous sample from eggshell is highest compared to the others. It can be seen that the total porosities measured by mercury intrusion porosimeter of porous specimens are nearly the same trend as well as the thermal conductivity. It was found that the low-value calcium-rich wastes could be used for producing porous poly(phospho-siloxos) networks which could be utilized for thermal insulation applications.

Design of high performance materials for thermal insulation or heat sinking requires understanding of the mechanisms controlling heat flow. The effect of grain size on the effective thermal conductivity of porous alumina ceramics has been investigated. After uniaxial pressing of a fine α-alumina powder, control of firing temperature and duration yielded ceramics with variations in grain size. Values of thermal conductivity corresponding to equivalent 100% dense ceramics were determined from laser flash measurements using Landauer’s relation to take porosity into account. These exhibited a strong decrease from 33 W m−1 K−1, for grain sizes larger than 2 μm, down to 8 W m−1 K−1 for an average grain size of 0.25 μm. A method to separate the contributions of localized thermal resistance (Kapitza resistance) at grain boundaries and grain conductivity for each sample is presented. The larger grain size samples (>0.5 μm) yield values for the effective grain boundary thermal resistance in the range 0.6–0.8 × 10−8 m2 K W−1 and a grain conductivity close to 35 W m−1 K−1. For smaller grain samples (

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Neutron shielding materials, containing boron as the neutron absorbing element, are used as a biological protection in nuclear materials storage and transportation casks. In the present work, boron in the form of colemanite powder (Ca2B6O11·5H2O), was incorporated in a cementitious matrix. Localized quantification of boron is required to confirm that a homogeneous distribution in the matrix has been achieved. The elemental analysis of a neutron-shielding cement matrix containing boron in minor quantities (less than 1 to 2 wt% of boron) was made. The elemental analysis of mineral materials requires dissolution in most cases. The first challenge encountered was the determination of a dissolution protocol that leads to total dissolution of materials, namely cement, colemanite and other minerals, without losing volatile compounds such as borates. The next challenge was the elemental analysis itself. Numerous elements are present in the obtained solutions and could interfere with boron determination. Different boron titration techniques are reviewed out in order to choose the most suitable. In practice, the quantification of boron using an ICP-AES was very satisfactory but a second titration technique was needed to confirm ICP-AES results. The titration of boron using the carminic acid assay was chosen. In order to remove interfering ions, a simple laboratory made purification device was set up. A protocol was developed in order to measure the boron concentration by the carminic acid assay. This led to consistent data with ICP-AES results.

Selective Laser Sintering (SLS) technique is used to fabricate 3D porcelain products with complex shapes. Commercial powder has been studied and optimized in terms of morphology and particle size distribution in order to get a perfect powder layerwise which remains the critical step of such a technique. The influence of laser energy density (through the laser power and scan speed) and hatching space have been investigated to determine the optimized parameters that allow the greater densification of this complex multi-materials composed of kaolinite, quartz and potassium feldspar. The laser-sintered porcelain products which exhibit about 60% of porosity have been post-treated at 1350 °C under vacuum or air to further improve densification.

In the present work the modifications induced by the geomimetic processing on the environment of silicon and aluminum atoms are finely characterized by solid state MAS NMR. The raw clay (Lat), a lateritic clay from Yaounde (Cameroon), contains kaolinite, quartz, hematite and goethite as major mineral phases. This material is treated under acidic conditions during 24 h (LatAF) and then under alkaline conditions during 18 days, leading to the final consolidated “geomimetic” product (LatAFCH). The samples have been characterized by 29Si and 27Al solid state NMR at each step of the process.The NMR spectra obtained for the starting clay indicate the presence of AlIV and AlVI populations together with silicon Q2 (0 or 1Al) and Q3 (0 or 1Al) environments located at δiso=-83 ppm and δiso=-91 ppm respectively.The acidic reaction during 24 h, does not significantly affect the silicon-rich layers. It induces a conversion of part of AlIV population into AlVI environment mainly related to the occurrence of six-fold organo-aluminum complexes when using fulvic acid. With inorganic acid, Al dissolution prevails.The neutralization (using lime) of the medium, followed by ageing for 18 days, promotes clay interactions with available calcium ions. The newly formed phases are cementitious CSH, CASH and CAH phases.

The effectiveness of two amorphous silica based wastes, rice husk ash and volcanic ash powders, used to act as structural reinforcement and partial replacement of metakaolin in porous matrices for thermal isolation was assessed. Both wastes produced colloidal phase that contributed to improve the reactivity and homogeneity of the matrices enhancing the mechanical strength. Rounded pores were obtained in relation with significant reduction of the interpore partitions under controlled addition of the blowing agent. The bulk thermal conductivity decreased from 0.6 to less than 0.15 W m −1 K −1 with the increase of the concentration of blowing agent. The final matrix presented pore size distribution and pore connectivity that allows analytical description and prediction of their effective thermal conductivity.Results demonstrated that clear relations can be established among the viscosity of the pastes, chemical composition, amount of blowing agent and the volume expansion/pore size distribution.

International audience; Rice hush (R) and volcanic (P) ashes, two recycled natural wastes were used for their high amorphous silica to improve the homogeneity and structure composition of inorganic polymer pastes before the expansion with aluminum powder. The fine powders were found to be appropriate in enhancing the geopolymerization and expansion conducting to lightweight structure with pore size and pore distribution linked to the viscosity, the concentration of blowing agent, and the crystalline nature of the waste. From the Stereo optical microscope, environmental scanning microscope and the mercury intrusion porosimetry used for the characterization, it appeared that in the interval of complete percolation of the skeleton, there exists correlation between the viscosity, expansion, roundness of pores, pores size distribution. The interpretation of the microstructure of porous geopolymer in this interval allows the description of their effective thermal conductivity with the Maxwell–Eucken model and the novel effective medium theory proposed recently.

The paper describes the ceramic top coats of Thermal Barrier Coatings (TBC) obtained by Suspension Plasma Spraying (SPS). The spray process realized with different plasma torches allowed obtaining coatings having different morphology, namely, columnar-like and two-zones microstructure. The microstructures influenced the thermal transport properties of TBC's. The study analyses the thermophysical properties of yttria and yttria- with ceria- stabilized zirconia coatings, i.e. YSZ and YCeSZ, respectively. The spray processes were realized with the use of three different plasma spray torches: (i) SG-100; (ii) Axial III and (iii) hybrid WSP one. The deposition parameters were designed for each plasma torch separately. The microstructure of coatings was then analyzed using Optical and Scanning Electron Microscopy i.e. OM and SEM, respectively. The thermophysical properties of the coatings such as density, specific heat and thermal dilatation were measured using gas pycnometry, calorimetry and dilatometry methods respectively. The collected data were used, together with thermal diffusivity found with the use of laser flash method, to calculate the thermal conductivity of the deposits. The thermal conductivities of coatings were in a range from 0.63 to 0.99 [W/m·K] for YSZ samples and between 0.82 and 1.37 [W/m·K] in the case of YCeSZ coatings. Thermal transport properties were found to be influenced by the coatings' porosity and their microstructure. Finally, the thermal conductivity values were successfully validated using response function method, which can be an alternative to complex FEM methods.

International audience; The effect of humidity on the dielectric constant and electrical impedance of porous 8 mol% yttria stabilized zirconia ceramic is examined. Samples with pore volume fractions from 33% to 55% were prepared from a fine powder by uniaxial pressing and firing. Measurements, in different relative humidities from

International audience; Experimental results and theoretical models are used to assess the effective thermal conductivity of porous inorganic polymer cements, often indicated as geopolymers, with porosity between 30 and 70. vol.%. It is shown that the bulk chemical composition affects the microstructure (grains size, pores size, spatial arrangement of pores, homogeneity, micro cracks, bleeding channels) with consequently the heat flow behaviour through the porous matrix. In particular, introduction of controlled fine pores in a homogeneous matrix of inorganic polymer cements results in an increase of pore volume and improvement of the thermal insulation. The variation of the effective thermal conductivity with the total porosity was found to be consistent with analytical models described by Maxwell-Eucken and Landauer.

Two sets of highly porous materials with different intrinsic thermal conductivity values for the solid skeleton were prepared: zirconia and alumina. Microstructural characterisation was performed, including the determination of the pore size distribution (PSD). The pore volume fraction was varied from 40 to 75%. Zirconia samples exhibit heterogeneous microstructures with a bimodal PSD. Alumina samples seems to be more organised with a monomodal PSD. The effective thermal conductivity was evaluated using the laser-flash technique. The experimental values were compared with predictions made with analytical models as a function of porosity. In particular, effective medium percolation theory (EMPT) for a two-phase system gives calculated values which are close to the experimental results for zirconia samples when the bimodal PSD was taken into account. Measurements on alumina samples have shown that EMPT is of limited use for an organised microstructure with porosity exceeding 65%. Complementary studies by computer simulation were also used to support some of the deductions which were made concerning the influence of the microstructure organisation on the effective thermal conductivity.

Inorganic polymer cement paste was used as cleaner binder for the design of lightweight matrices as insulating envelopes and panels in building and construction industries. Sponge-like structure with a homogeneously distributed pore network, low density and low thermal conductivity permitted to classify the geopolymer–wood fiber composites promising clean insulating materials. Matrices with the density ∼0.79 g/cm3, bi-axial four-point flexural strength of ∼4 MPa presented thermal conductivity between 0.2 and 0.3 W/(m K). The possibility of substituting the sodium silicate with rice ash-NaOH system and the efficiency of the matrices to constitute an effective tortuous road for the thermal gradient improved the sustainability and quality of this new class of products. The pores network and the microstructure approximated by a spatial periodic geometry suggested a “macro transport” mechanism to explain the movement of heat across the matrix of light geopolymer composite.

The paper describes the procedure of determination of thermal properties (thermal diffusivity and thermal conductivity) of yttria/ceria stabilized zirconia coatings. The coatings were deposited by suspension plasma spraying method using SG-100 torch. The commercial powder with a chemical composition ZrO 2 + 24 wt.% CeO 2 + 2.5 wt.% Y 2 O 3 was used and coatings were sprayed onto stainless steel substrates. The suspensions consisted of zirconia powder, water, ethanol and small addition of dispersant. The design of spray experiments included the following variable process parameters: (i) spray distance; and (ii) torch scan linear speed. The microstructure of coatings was determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The phase composition and the crystallite size of coatings were estimated by Rietveld method. The different methods were used to find out the thermal properties values up to 573 K. Firstly, thermal diffusivity of YCSZ coatings was determined by using a commercial setup and the obtained results were used to calculate the values of thermal conductivity. Then, to check the validity of the measurements and calculations, the simulations of laser flash experiment were made using COMSOL Multiphysics software. The least square method enabled to find the optimized value of thermal conductivity. Finally, the use of another setup enabled to find out the thermal transport properties in the temperature up to 873 K.

International audience; This work is dealing with the thermo mechanical behaviour of a new composite material used as thermal insulator and for fire passive protection in building construction. The composite panel results of combination of a calcium sulphate hydrates matrix mainly water and inorganic mineral additives. The effective thermal conductivity of the composite is measured by the hot-disc method. Analytical and numerical models are used to determine the composite thermal conductivity which can be expected vs the rate of additives. The experimental values are compared with analytical and numerical models. In particular, effective medium percolation theory (EMPT) for a two-phase system gives analytical values which are close to the experimental results. Moreover, the numerical model based on a simple description can allow the description of the thermal conductivity evolution with the rate of additives. An unexpected phenomenon which can be attributed to the confined water in additives can explain the gap between the numerical models and the experimental results.

Highly porous zirconia ceramic with nanometric sized grains was prepared from an 8 mol% yttria stabilised zirconia suspension mixed with a commercial latex. The pore volume fraction was varied from 45 to 75% by adjusting the thermal treatment between 750 and 1100 °C. Observations of the microstructure reveal variation in pore shape and size. Mean grain sizes are less than 70 nm. Mercury porosimetry measurements reveal a bimodal pore size distribution. Thermal diffusivity measurements were made with the laser flash technique in order to determine the thermal conductivity at room temperature. The thermal conductivity approaches a lower limit of 0.1 W m −1 K −1 . Experimental results were shown to agree closely with predictions made with Landauer's effective medium expression for a two-phase system. The agreement was improved even further by taking into account the interfacial thermal resistance of the grain boundaries and the pore size distribution.

International audience; The influence of (i) the ice front velocity in the freeze–casting process as well as the addition of two binders, (ii) the inorganic synthetic mineral laponite and (iii) the natural organic oligomer chitosan, on the microstructure and on thermal conductivity of bentonite materials prepared using the freeze–casting process were investigated by scanning electron and interferometric microscopies and the laser flash method. Prior to measurements, materials physico-chemical characteristics were determined using specific surface area, grain size and density measurements. Results show that the width of the strongly oriented pores obtained with the freeze–casting process is modified by the presence of binders, and that in turn, the thermal conductivity and anisotropy are also significantly modified.

International audience; This work presents the thermal properties of ytterbium-doped yttrium aluminium garnet (Yb:YAG) transparent ceramics at elevated temperatures in dependence on the dopant concentration and on temperature. Transparent polycrystalline Yb:YAG ceramics were prepared by solid-state reaction of oxide powders sintered under high vacuum. The dopant amount varied from 0 to 20 at.% of Yb. Thermal diffusivity of the sintered samples was measured by the laser and xenon flash methods at temperatures ranging from room temperature to 900°C. Both the thermal diffusivity and thermal conductivity values decreased with increasing dopant content, and until 500°C a decrease was observed also with increasing temperature. When available, the measured values were compared to data published in literature, and were found to be in good agreement. Based on the measured values, empirical relations in the form of shifted power laws are proposed for the temperature dependence of thermal diffusivity.

International audience; A clay-based material exhibiting high pore volume fraction andlow thermal conductivity suitable for thermal insulation isdescribed. Starting with a commercial clay containing >75% kaolinite,foams were made by mixing in water and methyl celluloseas a surfactant then beating. After drying at 70°C, the pore volumefraction >94% remains almost constant for treatments upto 1150°C. In contrast, the phases constituting the solid skeletonevolve strongly with removal of surfactant, dehydroxylation ofkaolinite, and formation of mullite. The latter leads to greatermechanical strength but also an increase in thermal conductivity.Thermal treatment of the kaolin foam at 1100°C yields a suitablecompromise between low thermal conductivity of 0.054W.(m.K) – 1 at room temperature with a compressive yield stressof 0.04 MPa. The radiation component in the effective thermalconductivity is 50% at 500°C

International audience; The present work aimed to investigate the interactions that control the strengthening of ''geomimetic'' materials. The raw lateritic clay used mainly contained kaolinite, goethite, quartz and hematite. The processing involved a 24 h-reaction with fulvic acid followed by neutralization with lime or with NaOH prior to the curing at 60 C for 18 days under water saturated atmosphere. The compressive strength and thermal conductivity after consolidation were respectively 0.7 MPa and 0.19Wm 1 K 1 for lime-based products, and 0.78 MPa and 0.3Wm 1 K 1 for soda-based products. The latter exhibited low durability in water. Such differences could be related to the high degradation of kaolinite particles when using NaOH, leading to the formation of sodalite, cancrinite and nontronite, which phases did not act as binder. Cementitious CAH and CSH phases were obtained when using lime. Rheological measurements performed on lime-based samples indicated that a shear-thinning behavior prevails up to the 7th day of curing. Above this period, the samples reached a determinant step whereby a solid-like behavior became predominant. The occurrence of binding precursors during the first 7 days of curing conducted to a progressive increase of the yield stress and consistency from 1 to 53 Pa and from 0.2 to 2.3 Pa s, respectively.

International audience; Incorporation of porosity into a monolithic material decreases the effective thermal conductivity. Porous ceramics were prepared by different methods to achieve pore volume fractions from 4 to 95%. A toolbox of analytical relations is proposed to describe the effective thermal conductivity as a function of solid phase thermal conductivity, pore thermal conductivity, and pore volume fraction (νp). For νp < 0.65, the Maxwell–Eucken relation for closed porosity and Landauer relation for open porosity give good agreement to experimental data on tin oxide, alumina, and zirconia ceramics. For νp > 0.65, the thermal conductivity of kaolin-based foams and calcium aluminate foams was well described by the Hashin Shtrikman upper bound and Russell’s relation. Finally, numerical simulation on artificially generated microstructures yields accurate predictions of thermal conductivity when fine detail of the spatial distribution of the phases needs to be accounted for, as demonstrated with a bio-aggregate material.

The present work aims to investigate a new composite used in building construction. The starting products are an industrial plaster, mica, vermiculite and water. The chemical characterization of the matrix reveals the presence of dihydrate (5 wt%) in plaster which modifies the setting time of the hydration process. This phenomenon is not observed with a pure plaster suggesting that another parameter modifies the kinetics: the particle size. Indeed, the setting time decreases of 30 min when the plaster is sieved from 150 to 10 μm. The evolution of the thermal properties versus the nature and the quantity of additives is also studied. Vermiculite proves to be well suited to decrease the thermal conductivity of the panel (0.58–0.27 W m−1 K−1) whereas mica tends to increase it. The analytical model of Hashin and Strikman well describe the evolution of the thermal conductivity until a porosity of 40%.

International audience; This paper reports about the development of a modified laser-flash technique and relation to measure the in-plane thermal diffusivity of thin polycrystalline oxide samples. Thermal conductivity is then calculated with the product of diffusivity, specific heat and density. Design and operating features for evaluating in-plane thermal conductivities are described. The technique is advantageous as thin samples are not glued together to measure in-plane thermal conductivities like earlier methods reported in literature. The approach was employed to study anisotropic thermal conductivity in alumina sheet, textured kaolin ceramics and montmorillonite. Since it is rare to find in-plane thermal conductivity values for such anisotropic thin samples in literature, this technique offers a useful variant to existing techniques.

International audience; In this work are given some thermal and mechanical properties of monazite, related to the microstructure. This compound is a poor thermal conductive (lambda < 5 W m(-1) K-1), with a thermal expansion in between 9 and 10 x 10(-6) K-1 according to the considered crystallographic direction, and a relatively high specific heat (C-p approximate to 110 J mol(-1) K-1). Mechanical properties of monazite are characteristic of a brittle behavior: bending strength is of about 100 MPa and fracture toughness is close to 1 MPa m(1/2). Porosity plays a large role on both thermal and mechanical properties pointing out the importance of controlling the whole elaboration process.

This work is about the calculation of thermal conductivity of insulating building materials made from plant particles. To determine the type of raw materials, the particle sizes or the volume fractions of plant and binder, a tool dedicated to calculate the thermal conductivity of heterogeneous materials has been developped, using the discrete element method to generate the volume element and the finite element method to calculate the homogenized properties. A 3D optical scanner has been used to capture plant particle shapes and convert them into a cluster of discret elements. These aggregates are initially randomly distributed but without any overlap, and then fall down in a container due to the gravity force and collide with neighbour particles according to a velocity Verlet algorithm. Once the RVE is built, the geometry is exported in the open-source Salome-Meca platform to be meshed. The calculation of the effective thermal conductivity of the heterogeneous volume is then performed using a homogenization technique, based on an energy method. To validate the numerical tool, thermal conductivity measurements have been performed on sunflower pith aggregates and on packed beds of the same particles. The experimental values have been compared satisfactorily with a batch of numerical simulations.

The present thesis is part of a long-term objective to control the drying step of ceramic green bodies in real-time. Given this general aim, the present work is based on two complimentary parts. The first part deals with the measurement of drying parameters (sample temperature, moisture content and dimension changes by an optical method). Then, since the ultimate objective of this work is the construction of a numerical model, an experimental evaluation of physical properties involved during drying is made for input into the model. The current study is focused on two technologically important materials frequently used in the ceramic industry which are alumina and clays (kaolin here). Alumina is one of most common raw materials used in technical ceramics and kaolin is typically used in traditional ceramics. Experimentally, the macroscopic drying behaviour of both materials zqs determined as well as the dependence of physical properties (in particular the diffusion coefficient and the thermal conductivity) on moisture content as drying proceeds. Furthermore, a study on the spatial distributions of water within the ceramic green body at different scales (MRI and ESEM) is used to interpret how physical properties vary with moisture content. Then, from the examination of numerous situations of drying, we concluded that the proposed numerical model yields good predictions of moisture content and the green body temperature. These parameters can help to evaluate progress in the drying step with eventual feedback in process control.; Cette thèse s’inscrit dans un objectif à long terme de contrôle et de pilotage en temps réel du séchage des produits céramiques. Pour cela, cette étude se décompose en deux volets. Une première partie expérimentale qui porte sur la détermination en temps réel des paramètres de séchage (température de l’échantillon, teneur en eau et variations dimensionnelles par méthode optique). Une seconde partie, quant à elle, consiste à étudier l’évolution des propriétés physiques des matériaux pendant le séchage pour ensuite construire un modèle numérique macroscopique qui utilise ces données expérimentales. Deux matériaux céramiques ont été choisis pour cette étude : une alumine et une argile kaolinitique. L’alumine a été choisie pour son utilisation fréquente dans les céramiques techniques et le kaolin dans les céramiques traditionnelles. La partie expérimentale de cette étude a permis de déterminer le comportement macroscopique au séchage des deux matériaux ainsi que d’évaluer la dépendance des propriétés physiques (en particulier le coefficient de diffusion et la conductivité thermique) avec la teneur en eau. De plus, une étude à une échelle plus petite par RMN et microscopique par MEB environnemental a permis de mettre en relation l’évolution des propriétés physiques avec la localisation de l’eau au sein du matériau pendant le séchage. Puis, à partir de l’évaluation de nombreuses situations de séchage, les prédictions numériques se sont avérées être en bon accord avec les résultats expérimentaux. Pour conclure, ce modèle représente un bon moyen pour contrôler l’étape de séchage.