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China's Refractories 2024年第2期33卷 1-9页

作者： Marc HUGER Glyn DERRICK Mossaab MOUIYA Andrea SALERNO Kwasi Addo BOATENG Hrikeshava RANGANATHAN Amit Kumar GOPE Institute of Research for Ceramics(ircer-UMR CNRS 7315) University of LimogesLimoges 87000France

The movement of the Iron&Steelmaking(I&S)industry towards Net-Zero emissions and digitalized processes through disruptive,breakthrough technologies will be achieved through the use of *** biggest challenge for the refractory industry is to continue to meet the performance expectations while,at the same time,moving to a more sustainable production *** complexity and urgency of these technological changes,highlighted by the European Green Deal,requires ambitious,international,interdisciplinary and intersectoral projects,bringing together institutes from across the global value chain,to carry out cutting edge *** European Union,through its flagship doctoral training program,MSCA,has,and continues to support research and development as well as the promotion of the refractory industry in *** introduction to two MSCA projects and some of the results achieved are highlighted within this article.

关键词： FIRE network Horizon 2020 Horizon Europe Marie Sklodowska-Curie Actions Doctoral networks European Green Deal

What If the Protection against Oxidation of Chromia-Forming Alloys Was Not Always Due to the Chromia Layer?

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American Journal of Analytical Chemistry 2024年第9期15卷 286-302页

作者： Boris Contri Stéphane Valette Marina Soustre Pierre Lefort ircer European Ceramics Centre UMR CNRS 7315 University of Limoges 12 rue Atlantis Limoges Cedex France

Chromia-forming alloys have good resistance to oxidizing agents such as O2, CO2, … It is accepted that the protection of these alloys is always due to the chromia layer formed at the surface of the alloys, which acts as a barrier between the oxidizing gases and the alloy substrates, forming a diffusion zone that limits the overall reaction rate and leads to parabolic kinetics. But this was not verified in the study devoted to Inconel®625 the oxidation in CO2 that was followed by TGA, with characterizations by XRD, EDS and FIB microscopy. Contrary to what was expected and accepted in similar studies on other chromia-forming alloys, it was shown that the diffusion step that governs the overall reaction rate is not located inside the chromia layer but inside the alloy, precisely inside a zone just beneath the interface alloy/chromia, this zone being depleted in chromium. The chromia layer, therefore, plays no kinetic role and does not directly protect the underlying alloy. This result was demonstrated using a simple test that consisted in removing the chromia layer from the surface of samples partially oxidized and then to continue the thermal treatment: insofar as the kinetics continued without any change in rate, this proved that this surface layer of oxide did not protect the substrate. Based on previous work on many chromia-forming alloys, the possibility of a similar reaction mechanism is discussed. If the chromia layer is not the source of protection for a number of chromia-forming alloys, as is suspected, this might have major consequences in terms of industrial applications.

关键词： Chromia-Forming Alloys Chromia Layer Oxidation Protection Inconel®625 Kinetics

Use of a Microwave Plasma Process at Atmospheric Pressure for Bacterial Inactivation without Thermal Effects

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Materials Sciences and Applications 2023年第5期14卷 285-298页

作者： Laura Renoux Christelle Dublanche-Tixier Christophe Chazelas Pascal Tristant Patrice Valorge Corinne Maftah Patrick Leprat University of Limoges CNRS IRCER UMR 7315 Limoges France University of Limoges E2Lim UR 24133 Limoges France

An atmospheric microwave plasma argon was used for the inactivation of bacteria E. coli. The employed device, called Axial Injection Torch (or TIA for Torche à Injection Axiale), consisted of a microwave power source, a waveguide and a gas supply system. Using this argon plasma source, we studied the effects of the exposure time, the exposure distance, the input power, and the gas flow rate on the reduction rate of Escherichia coli cells. The first part of the study was carried out with a static sample exposed to the plasma and then in the second part the sample was set in motion relative to the plasma jet. A log reduction number of E. coli of 4 (10-4 CFU/mL) was obtained with UV and active species, for UV only a log of 1 (10-1 CFU/mL) was obtained.

关键词： Atmospheric Pressure Plasma Microwave Plasma Torch Disinfection Bacteria

Physicochemical Characterisation for Potential Uses as Industrial Mineral of Bauxite from Débélé, Guinea

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Journal of Materials Science and Chemical Engineering 2021年第3期9卷 9-22页

作者： Mamadou Yaya Balde Chantale Njiomou Djangang Ramatoulaye Binta Diallo Philippe Blanchart Daniel Njopwouo Department of Inorganic Chemistry University of Yaounde I Yaounde Cameroon Department of Chemistry University Gamal Abdel Nasser of Conakry Conakry Guinea Institute of Research for Ceramics—ircer Limoges France

Assessing the potential uses as industrial mineral, bauxite from Débélé, Guinea, has been characterised by chemical and mineralogical analyses, the determination of the amorphous content, the rate of portlandite consumption in an aqueous solution, the strength activity index, and the thermal behaviour up to 1200°C. It was evidenced that the raw sample is gibbsite-rich type bauxite with about 45.06 wt% of alumina, 23.80 wt% of iron oxide, and 1.74 wt% of silica. It meets the chemical composition required for bauxites used for refractory cement. During heating, the raw bauxite undergoes high densification with low linear shrinkage, motivating a potential use in dense ceramic compositions with high thermal stability. Also, the heating at only 600°C gives a significant pozzolanic activity in combination with Portland cement. The correlation between the pozzolanicity, the amorphous phase content, and the specific surface area indicated that the raw and the calcined materials present an interesting reactivity for using them in alternative cement formulations.

关键词： Bauxite Characteristics Industrial Mineral Guinea

Manufacture of Industrial Refractory Crucibles Based on Clays from Burkina Faso

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 79-90页

作者： Kassoum Barry Youssouf Sawadogo Moustapha Sawadogo Brahima Sorgho Mohamed Seynou Boubié Guel Philippe Blanchart Lamine Zerbo Laboratory of Molecular Chemistry and Materials (LC2M) University Joseph KI-ZERBO Ouagadougou Burkina Faso Institute of Research for Ceramic (ircer) European Ceramic Centre (CEC) Limoges France

In Burkina Faso, one of the three largest gold producers in West Africa, foundry activity is often paralyzed when basic equipment such as crucibles and cups are not available or should be imported. However, previous studies have shown the availability of kaolinite-rich clay resources that could be used for the local manufacture of silico-aluminous ceramic crucibles. This work allowed to manufacture industrial ceramic crucibles with local clays and then they were tested in foundry industry. The materials were manufactured from three (03) raw materials including two clays (SAB and ROU) and sand. The chemical and mineral analysis has shown that the raw materials are suitable for the formulation of refractory materials. The results of characterization of the materials formulated showed that the properties of use are appreciable. The porosity of the materials is relatively low (23 - 28 vol%) with a diametral compressive strength between 0.61 and 1.34 MPa. Crucibles sintered at 1250˚C with a stay of 2 hours have a mechanical strength capable of supporting the weight of the ores contained. These crucibles have a refractoriness under load (T0.5) above 1141˚C and resist chemical attacks. Tests were carried out in the industry at 1100˚C, and the results were satisfactory.

关键词： Refractory Foundry Activity Compressive Strength Chemical Resistance

Two-Dimensional Stochastic Rotation Dynamics for Fluid Simulation

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Journal of Computer and Communications 2020年第2期8卷 27-38页

作者： Benoit Crespin Cong Tam Tran Manuella Cerbelaud Arnaud Videcoq Emmanuelle Darles University Limoges XLIM/ASALIUMR CNRSLimogesFrance Center for Mathematical Modeling SantiagoChile University Limoges IRCERUMR CNRSLimogesFrance University Poitiers XLIM/ASALIUMR CNRSPoitiersFrance.

This paper presents a new method for fluid simulation based on Stochastic Rotation Dynamics. The SRD model relies on a particle-based representation, but does not consider incompressibility. We generalize this model by introducing additional computation steps in order to handle this type of behavior, and also two-way coupling between the fluid and immersed objects. As a proof of concept, our method is implemented on the CPU to produce different types of simulations such as dam-break flood, falling droplets and mixing of two fluids.

关键词： Computer Graphics Fluid Simulation Particle Systems

Phase Transformation, Technological Properties and Microstructure of Fired Products Based on Clay-Dolomite Mixtures

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Journal of Materials Science and Chemical Engineering 2019年第11期7卷 1-14页

作者： B. S. Gonidanga D. Njoya G. Lecomte-Nana D. Njopwouo Laboratory of Applied Inorganic Chemistry University of Yaounde 1 Yaounde Cameroon ircer—University of Limoges Limoges France Water Management Lavoisier Hydrosciences Laboratory University of Bangui Faculty of Sciences Bangui Central African Republic

The present work reports the effect of carbonate addition to iron rich kaolinite on the phase transformation during firing. Mineralogical, thermal (including DTA-TGA and dilatometric) and physico-mechanical analyses were performed on fired product made from a mixture of kaolinite and 8% by mass of dolomite. The firing temperatures used are 920°C, 1050°C, 1150°C, 1200°C and 1250°C. The major mineral phases formed during firing are mullite, cristobalite and hematite associated to gehlenite and anorthite at temperature >1150°C. Their presence induces increased densification of the product that results in an increased in the flexural strength up to 1150°C. Beyond this temperature, increase glassy phase formation together with hematite development, induce a decrease of the flexural strength as well as the porosity and water adsorption. The SEM observations show that primary mullite is formed as from 1150°C. The EDS analysis from SEM is coherent with the chemical and the mineralogical analyses from XRD. The overall analyses indicate that the addition of dolomite at 8% by mass is favorable to vitreous ceramic formation as from 1050°C.

关键词： Clayey Materials Dolomite Kaolinite Phase Transformation Microstructures

Formulation of Geopolymer Cements from Two Clays Containing Kaolinite and Muscovite: Effect of Temperature on the Physicomechanical Properties of the Products

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Journal of Materials Science and Chemical Engineering 2023年第12期11卷 34-45页

作者： Mamadou Yaya Balde Diaka Sidibe Éric Severin Simo Bakam Chantale Djangang Njiomou Philippe Blanchart Laboratory of Applied Inorganic Chemistry University of Yaoundé 1 Yaoundé Cameroon Laboratory of Physical and Colloidal Chemistry Gamal Abdel Nasser University of Conakry Conakry Guinée Center for Waste Management Research (CREGED) Conakry Guinea Higher Institute of Mines and Geology of Boké (ISMGB) Boké Guinea Institute of Research for Ceramics (ircer) Limoges France

The paper talks about the elaboration of geopolymer with two types of kaolinite clays containing muscovite. The kaolinite materials were first calcined at different temperatures, and mixed with an activator solution, called liquid precursor, at a different solid/liquid mass ratio depending on their normal consistency to produce geopolymer binders. Results show that the geopolymer products obtained from the different clays have good physichomechanical properties: their open porosity and their water absorption rate decrease while their compressive strength and their apparent density increase with the increase in calcination temperature of the clays. The density of GABD binders varies between 2.92 and 2.47 g/cm3 and that of GARD binders between 1.86 and 2.16 g/cm3. Specimens in the GABD series have the best mechanical performance, ranging from 14.43 to 31.37 MPa, while those in the GARD series oscillate between 6.18 and 11.56 MPa. These properties make kaolinite materials from this region suitable for use as construction materials for adequate waterproof structures.

关键词： Geopolymer Cements Kaolinitic Clays Muscovite Permeability Mechanical Strength

Vasarely painting at the nanoscale on sapphire crystals

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Nano Research 2020年第9期13卷 2512-2516页

作者： Caroline Matringe Elsa Thune Rémy Cavalotti Ahmad Fakih Stephan Amaud Nils Blanc Nathalie Boudet Alessandro Coati Yves Garreau David Babonneau René Guinebretière ircer UMR CNRS 7315Centre Europeen de la CeramiqueUniversite de Limoges12 rue Atlantis87068 LimogesFrance Institut Neel UPR CNRS 2940 CRG D2AM BeamlineESRFUniversite Grenoble Alpes38042 GrenobleFrance SixS Beamline Synchrotron SOLEILBP4891192 Gifsur YvetteFrance Laboratoire Materiaux et Phenomenes Quantiques UMR CNRS 7162Universite de Paris75013 ParisFrance Institut Pprime Departement Physique et Mecanique des Materiauxf UPR CNRS 3346Universite de PoitiersSP2MITSA 4112386073 Poitiers Cedex 9France

We demonstrate that convenient thermal treatment of a specific sapphire vicinal surface can induce the formation of a fully two-dimensional(2D)ordered surface made of a periodic assembly of(006)*** simiarity between the resuting surface topography and pattemns represented in the hexagon series"of paintings by Vasarely is really striking!We thus propose to call these surfaces as"nanoscaled Vasarely surfaces".We also show that the self-organization process,which is driven by the minimization of the free energy of a closed system,results in a quasi-linear isothermal growth of the facets'surface area over time.

关键词： nanoscaled Vasarely surfaces two-dimensional(2D)-self-organization sapphire vicinal surfaces

Optimization of Contents of Three Raw Clay Materials in Formulation of a Porcelain

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Journal of Materials Science and Chemical Engineering 2022年第1期10卷 41-58页

作者： Youssouf Sawadogo Moustapha Sawadogo Moussa Ouédraogo Mohamed Seynou Gisèle Lecomte-Nana Philippe Blanchart Moussa Gomina Lamine Zerbo Laboratory of Molecular Chemistry and Materials (LC2M) University Joseph KI-ZERBO Burkina Faso Institute of Research in Ceramic (ircer) UMR-CNRS European Ceramic Center Limoges France Laboratory of Cristallography and Material Sciences (CRISMAT) UMR National Graduate School of Engineering of Caen (ENSICAEN) Caen France

Formulation of traditional hard porcelain generally requires 50% kaolin, 25% silica and 25% feldspar. Four porcelains formulation using the casting method, were prepared with different percentages of kaolinitic clay, sand and pegmatite referenced respectively NONG, SAB and PEG. The physico-chemical, mechanical and mineralogical characteristics were evaluated on specimens formulated and sintered at different temperatures from 1200˚C to 1300˚C. X-ray diffraction has revealed the presence of mullite and quartz as essentially crystalline phases. The specimen formulated with 55% NONG, 25% PEG and 20% SAB and sintered at 1240˚C gives better performance (water absorption: 0.17%, density: 2.42, open porosity: 0.42% and flexural strength: 53.54 MPa).

关键词： Raw Minerals Porcelain Characterization Chemical Durability and Phase Transformations