Campus Universitario Riu Sec

Castelló de la Plana, Spain

Campus Universitario Riu Sec

Castelló de la Plana, Spain
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De Noni Jr. A.,Instituto Maximiliano Gaidzinski | De Noni Jr. A.,Federal University of Santa Catarina | Hotza D.,Federal University of Santa Catarina | Soler V.C.,Campus Universitario Riu Sec | Vilches E.S.,Campus Universitario Riu Sec
Materials Science and Engineering A | Year: 2010

The porcelain tile is a ceramic product with high technical and aesthetic performance, whose composition is formulated from a mixture of clay or kaolin, quartz and feldspar. This paper is the first part of a study focusing on determining the influence of the porcelain tile composition on mechanical behaviour of sintered bodies. Seven compositions were prepared according to a simplex-centroid mixture design for a triaxial mixture, comprised of kaolinite, quartz and albite. The mixtures were processed reproducing industrial conditions: wet mixing followed by spray-drying, forming by pressing and fast firing with maximum temperatures ranged from 1210 to 1260 °C. The presence of kaolinite increases the dry apparent density in a significant way up to 30 wt%. Because of the fast firing, the microstructure is directly influenced by particle packing after forming. The internal porosity presented little change as a function of starting composition in the tested intervals. The surface porosity of the polished product increased with higher amounts of quartz. The results obtained in this first part of the study showed how the starting and end composition could generate the microstructure and suggest its influence on the mechanical properties of the porcelain tile, which will be later analysed in the second part of this paper. © 2009 Elsevier B.V. All rights reserved.

Molina T.,Campus Universitario Riu Sec | Vicent M.,Campus Universitario Riu Sec | Vicent M.,Jaume I University | Sanchez E.,Jaume I University | Moreno R.,Campus Universitario Riu Sec
Materials Research Bulletin | Year: 2012

Alumina-aluminium titanate (A-AT) composites are typically produced either by mixing the alumina matrix powder with already formed aluminium titanate or by reaction sintering of alumina and titania powders. Reaction-sintered materials usually exhibit limited final density and extensive microcracking. This paper describes the preparation of A-AT nanocomposites by slip casting and reaction sintering, using aqueous suspensions of submicrometre-sized alumina and nanometre-sized titania at a respective weight ratio of 87:13, which is typical for plasma-sprayed coatings. The colloidal stability of aqueous suspensions of the two individual powders and of their respective mixtures was determined first, measuring zeta potential and rheological behaviour as a function of deflocculant content and sonication time. The bimodal distribution yielded green relative densities of up to 70% of theoretical density. Dynamic and static sintering studies showed that aluminium titanate had already formed at 1400°C. © 2012 Elsevier Ltd.

Bonache V.,Polytechnic University of Valencia | Salvador M.D.,Polytechnic University of Valencia | Busquets D.,Polytechnic University of Valencia | Burguete P.,University of Valencia | And 3 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2011

Nanocrystalline tungsten carbide has been obtained by reduction/ carburization at low temperature from precursors obtained by freeze-drying of aqueous solutions. Nanocrystalline WC powders with a adequate content of carbon were mixed with submicrometric Cobalt powder (12 wt.%), obtained by same synthesis method, and sintered in vacuum furnace. The cemented carbides fabricated from experimental powders were compared with both commercial ultrafine and nanocrystalline WC-12Co mixtures consolidated by the same route. The synthesised powders were characterized by X-ray powder diffraction, elemental analysis and scanning and high resolution transmission electron microscopy. On the other hand, density, microstructure, hardness and fracture toughness together with X-ray diffraction analysis of the sintered materials were evaluated. The cemented carbides obtained from synthesised powders exhibited a WC platelet-based homogeneous microstructure. This anisotropic growth might be due to the presence of stacking faults parallel to the basal plane in the starting WC powder, which would promote the defect-assisted preferential growth. These materials showed excellent mechanical properties, with a superior hardness/fracture toughness combination compared to materials prepared from commercial mixtures. © 2010 Elsevier Ltd. All rights reserved.

Garcia-Ten J.,Campus Universitario Riu Sec | Monfort E.,Campus Universitario Riu Sec | Gomez-Tena M.P.,Campus Universitario Riu Sec | Sanz V.,Campus Universitario Riu Sec
Journal of Cleaner Production | Year: 2011

The manufacture of traditional ceramic products (ceramic tiles, roof tiles, and bricks) is often associated with the emission of F, Cl, and S compounds during the firing stage. According to the literature, fluorine emissions can be reduced by adding CaCO3 to the raw materials mixture used in fabricating these products. However, data available to the authors indicate that this procedure, which has been successfully applied in manufacturing structural ceramics (roof tiles and bricks), is ineffective in ceramic tile manufacture and modifies tile end properties. This paper examines the possibility of reducing such emissions by applying coatings of alkaline-earth carbonates on to the ceramic tile bottom surface to retain the acid compounds emitted during tile firing. The effectiveness of MgCO3, CaCO3, SrCO 3, and BaCO3 coatings for retaining these acid emissions was studied, using the evolved gas analysis (EGA) technique with a TG-DSC-FTIR-QM instrument. The SrCO3 coating was found to provide the greatest retention, showing that SO2 and HCl were retained more efficiently than HF. The presence of fluorides, chlorides, and sulphates of Ca, Sr, and Ba was verified in the respective fired coatings, confirming the existence of chemical reactions between the emitted acid compounds and the coating materials at high temperature. © 2010 Elsevier Ltd. All rights reserved.

Bautista Y.,Campus Universitario Riu Sec | Gomez M.P.,Campus Universitario Riu Sec | Ribes C.,Campus Universitario Riu Sec | Sanz V.,Campus Universitario Riu Sec
Progress in Organic Coatings | Year: 2011

Organic-inorganic hybrid materials can be defined as materials combining organic and inorganic domains in a nanometric scale. The development of these organic-inorganic hybrids has achieved properties from both organic and inorganic materials. In this research we have studied the scratch behaviour of coatings of organic-inorganic hybrid materials prepared by sol-gel processing, using as precursors, trialkoxysilanes with organic functionalities that react via free radical polymerization. We have also evaluated the influence of pure inorganic precursor as tetralkoxysilanes or pure organic precursors on the scratch behaviour. The main goal of this research was to evaluate how the chemical structure of the organic-inorganic hybrid influences the scratch behaviour of the coatings. © 2010 Elsevier B.V. All rights reserved.

Bautista Y.,Campus Universitario Riu Sec | Gonzalez J.,Campus Universitario Riu Sec | Gilabert J.,Campus Universitario Riu Sec | Ibanez M.J.,Campus Universitario Riu Sec | Sanz V.,Campus Universitario Riu Sec
Progress in Organic Coatings | Year: 2011

The nanoscratch test, used in this study, quantitatively characterizes the scratch behaviour of coatings. Some of the obtained parameters are plastic and elastic deformation, critical load to start the scratch, chipping or other change in the scratch mechanism of the coating. The knowledge of the scratch mechanism allows the optimisation of the material behaviour. In the present study the scratch resistance with the wear resistance has been correlated for nanocomposite coatings. Knowledge of mechanical properties extracted from the scratch test, supports the optimization of the coating against wear. The study was applied to nanocomposite coatings with different polymer matrices, different percentages and nature of nanoparticles. © 2010 Elsevier B.V. All rights reserved.

Portillo M.C.,Institute Recursos Naturales y Agrobiologia | Gazulla M.F.,Campus Universitario Riu Sec | Sanchez E.,Campus Universitario Riu Sec | Gonzalez J.M.,Institute Recursos Naturales y Agrobiologia
Journal of the European Ceramic Society | Year: 2011

Ceramic roofing tiles suffer deterioration through time due to environmental exposure. Biological colonization affects the appearance and integrity of building materials, such as roofing tiles. The resistance to biocolonization represents an important property affecting the product quality of ceramic roofing tiles. While natural colonization of roofing tiles by organisms is a progressive, heterogeneous, and slow process, laboratory assessment of this phenomenon requires a sensitive procedure that can be carried out within a reasonable period of time. Different microorganisms have been evaluated and the use of phototrophs, specifically the cyanobacterium Oscillatoria, presented several advantages such as good adherence, homogeneous growth on surfaces, and the chlorophyll-autofluorescence which can be used for a sensitive detection. Colonization by Oscillatoria on roofing tiles was assessed by measuring the autofluorescence of cells. This study proposes the use of specific cyanobacterial cells and a simple method for monitoring biofilm formation and biological colonization of roofing tiles. © 2010 Elsevier Ltd.

Garcia-Ten J.,Campus Universitario Riu Sec | Orts M.J.,Campus Universitario Riu Sec | Saburit A.,Campus Universitario Riu Sec | Silva G.,Campus Universitario Riu Sec
Ceramics International | Year: 2010

The thermal conductivity of traditional ceramic materials is known to be a function of their porosity or bulk density. However, the scatter in the thermal conductivity-bulk density data in certain studies, particularly when data from industrially processed brick are involved, suggests that thermal conductivity depends, apart from porosity, on other characteristics such as mineralogical composition, microstructure, humidity, and the presence of soluble salts. A standard red-firing clay used in brick manufacture has been used in this study with a view to systematising the impact of the different variables that could influence thermal conductivity and mechanical strength. Part I of the study presented the results obtained when the dry bulk density of the pieces and their firing temperature were modified. Part II examines the influence of the mineralogical composition of the starting raw materials mixture on the thermal conductivity and mechanical strength of clay brick products. The findings suggest that to manufacture traditional ceramics with high thermal insulation and appropriate mechanical properties, it is advisable to use illitic-kaolinitic clays. Large-sized potassium feldspar and quartz particles adversely affect fired mechanical strength. In addition, quartz has high thermal conductivity. The addition of carbonates or the use of calcareous clays has a positive effect on mechanical strength, because carbonate acts as a pore-forming agent and generates crystalline phases during firing that enhance mechanical strength. © 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Marti-Calatayud M.C.,Polytechnic University of Valencia | Garcia-Gabaldon M.,Polytechnic University of Valencia | Perez-Herranz V.,Polytechnic University of Valencia | Sales S.,Campus Universitario Riu Sec | Mestre S.,Campus Universitario Riu Sec
Ceramics International | Year: 2013

Cation-exchange membranes made exclusively from ceramic materials have been synthesized by means of the impregnation of microporous ceramic supports with zirconium phosphate. Changes in the pore size distribution and total pore volume of the supports were provoked by the addition of starch as pore former in the fabrication procedure. This allowed the production of supports with increased effective electrical conductivities and with larger pores available for the zirconium phosphate deposition. An improved functionality for the exchange of cations was given to the ceramic membranes by means of their impregnation with the active particles of zirconium phosphate. The ion-exchange properties of the membranes were increased with further impregnation cycles and the resulting current-voltage curves showed a similar shape to that typical of commercial polymeric ion-exchange membranes. The production of ion-exchange membranes with increased chemical and radiation stability will broaden their applicability for the treatment of specific industrial waste waters, which are very aggressive for the current commercial ion-exchange membranes. © 2012 Elsevier Ltd and Techna Group S.r.l.

Marti-Calatayud M.C.,Polytechnic University of Valencia | Garcia-Gabaldon M.,Polytechnic University of Valencia | Perez-Herranz V.,Polytechnic University of Valencia | Sales S.,Campus Universitario Riu Sec | Mestre S.,Campus Universitario Riu Sec
Desalination and Water Treatment | Year: 2013

In this article, the innovative cation-exchange membranes obtained from ceramic materials are presented. Different microporous ceramic supports were obtained from an initial mixture of alumina and kaolin, to which a varying content of starch was added in order to obtain supports with different pore size distributions. The deposition of zirconium phosphate into the porous supports generates membranes with cation-exchange properties. The fabrication of ion-exchange membranes which could resist aggressive electrolytes such as strong oxidizing spent chromium plating baths or radioactive solutions would allow the application of electrodialysis for the decontamination and regeneration of these industrial effluents. The performance of the manufactured membranes was studied in nickel sulfate solutions by means of chronopotentiometry. An increase of the membrane voltage drop during chronopotentiometric measurements was observed in some membranes, which seems to be a consequence of concentration polarization phenomena resulting from the ionic transfer occurred through the membranes. Current-voltage curves were obtained for the different ceramic membranes, allowing the calculation of their ohmic resistance. The ohmic resistance of the membranes increased when the open porosity (OP) of the samples was incremented up to a value of 50%. For values of OP higher than 50%, the resistance of the membranes decreased significantly with porosity. © 2013 Desalination Publications.

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