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FRACTURE-TOUGHNESS OF META-PHOSPHATE GLASSES

JOURNAL OF THE AMERICAN ceramic SOCIETY 1982年第5期65卷 C70-C70页

作者： ASHIZUKA, M BRADT, RC Ceramic Science and Engineering Program Department of Materials Science and Engineering The Pennsylvania State University University Park Pennsylvania 16802. On leave from Kyushu Institute of Technology Kitakyushu City Japan. Member the American Ceramic Society.

The fracture toughnesses and Young\'s elastic moduli of several metaphosphate glasses were measured by the indentation technique. The results show that the normal glasses lie along a KIcvs E line between (0.4, 40) and (0.7, 60) MPa‐m112and GPa, respectively. The abnormal ZnO and MgO metaphosphates appear to be tougher and are above the line of the normal glasse

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Electrical properties of lanthanum silicate apatite electrolytes prepared by an innovative chemical route

Electrical properties of lanthanum silicate apatite electrol...

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Symposium on Nanotechnology General Session - 225th ECS Meeting

作者： Macedo, G.L.S. Macedo, D.A. Rajesh, S. Martinelli, A.E. Figueiredo, F.M.L. Marques, F.M.B. Nascimento, R.M. Department of Chemical Engineering UFRN Natal59078-970 Brazil Department of Materials Engineering UFPB João Pessoa58051-900 Brazil Dept. of Materials and Ceramic Eng. CICECO University of Aveiro 3810-193 Portugal Materials Science and Engineering Postgraduate Program UFRN 59078-970 Brazil

ISBN: (纸本)9781607685869

This work reports the synthesis of apatite-type lanthanum silicate powders with nominal composition La10Si6O27 by an innovative chemical route which combines co-precipitation and sol-gel approaches. The herein proposed synthetic procedure is advantageous in reducing energy consumption and processing time, key elements to decrease the total manufacturing cost. The asprepared powder was calcined between 500 and 900 °C. Structure of the calcined powders, characterized by X-ray diffraction (XRD) and Rietveld refinement, indicated the formation of apatite crystalline lanthanum silicate with minor amount of L2O3 at 900 °C. The apatite powder was further analyzed by scanning electron microscopy (SEM). The effect of sintering temperature, ranging from 1400 to 1450 °C, on the electrical properties was investigated by impedance spectroscopy. Electrical measurements were recorded in the 400-800 °C temperature range. The lanthanum silicate electrolyte sintered at 1450 °C exhibited total electrical conductivity (σ700 °C = 2.12 × 10-3 ***-1) comparable with samples from literature prepared by sol-gel and freeze drying methods and sintered at 1500 °C. The results in the present study demonstrate that the co-precipitation method combined with a solgel approach is a promising alternative route to synthesize lanthanum silicate powders. © The Electrochemical Society.

关键词： Powders

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Rapid Synthesis of Crystalline Spinel Tin Nitride by a Solid-State Metathesis Reaction

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Journal of the American ceramic Society 2004年第1期85卷 101-104页

作者： Michael P. Shemkunas George H. Wolf Kurt Leinenweber William T. Petuskey Science and Engineering of Materials Program Department of Chemistry and Biochemistry and Materials Research Science and Engineering Center Arizona State University Tempe Arizona 85287-1604 Member American Ceramic Society.

Spinel tin nitride (Sn 3 N 4 ) was prepared by high-pressure solid-state metathesis reactions. Tin tetraiodide was reacted with lithium nitride and ammonium chloride in a piston–cylinder apparatus at 623 K and 2.5 GPa. Powder X-ray diffraction combined with Rietveld refinement confirmed the spinel structure, with a lattice constant of a = 9.0144(1) Å. Raman spectroscopy revealed five active vibrational modes at 160, 252, 416, 524, and 622 cm −1 , which are consistent with the spinel structure. Mid-infrared spectroscopy exhibited only a Sn–N stretching mode at 547 cm −1 . Transmission electron microscopy was used to reveal particle size and morphology. Electron probe microanalysis was used to verify the elemental composition.

关键词： synthesis spinels tin/tin compounds nitrides

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The behavior of different clays subjected to a fast-drying cycle for traditional ceramic manufacturing

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Journal of King Saud University - engineering sciences 2024年第5期36卷 339-348页

作者： Zaccaron, Alexandre de Souza Nandi, Vitor Dal Bó, Marcelo Arcaro, Sabrina Bernardin, Adriano Michael Program on Materials Science and Engineering Universidade do Extremo Sul Catarinense Avenida Universitária 1105 Santa Catarina Criciúma88806-000 Brazil SC Criciúma88813-600 Brazil Ceramic Materials Group Parque Científico e Tecnológico Rodovia Jorge Lacerda 3800 Santa Catarina Criciúma88807-400 Brazil

Studies have been widely carried out on drying techniques and equipment. The behavior of clays subjected to drying stages requires further research. This study aims to evaluate the behavior of the clay ceramic body during the different stages of the drying cycle and match the characteristics of the raw materials with the final quality of the pieces. In this work, the behavior of three different clays in terms of drying performance was studied. The clays were selected, and their chemical, mineralogical, and particle size characteristics were measured. The mixture design (DoE) developed 10 formulations and was processed through vacuum extrusion. The samples were subjected to forced drying cycles of 180 min by varying the temperature from 30 to 90 °C and air speed from 1.5 to 4.0 m/s. At the end of the cycle, the retraction was a determining factor for the crack probability indicator, where formulations that obtained ∼10% retraction in the dry zone showed losses >25%. On the other hand, it is could be stated that claystone assists the drying process of the ceramic piece, minimizing losses. The drying sensitivity coefficient (k-factor) presented values that reproduce the number of losses during drying, proving to be a valid tool to relate clay properties, drying conditions, and losses in this process. In this case, drying process losses >25% were observed when the k-factor was from 1.6. © 2022 The Authors

关键词： Drying

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Injectable Platelet-Rich Fibrin in Contact with Bone Substitutes, Porous Zirconia, or Laser-Textured Implant Surfaces: A Detailed Morphological Analysis

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Biomedical Materials and Devices 2024年第1期2卷 415-426页

作者： Oliveira, Miguel Noronha Varela, Hugo Almeida Nascimento, Rubens M. Sahoo, Narayan Carvalho, Oscar Henriques, Bruno Souza, Júlio C. M. Ceramic and Composite Materials Research Group (CERMAT) Department of Mechanical Engineering (EMC) Federal University of Santa Catarina (UFSC) Post-graduate Program in Materials Science and Engineering Federal University of Rio Grande Norte (UFRN) Center for MicroElectroMechanical Systems (CMEMS-UMINHO) Universidade do Minho LABBELS - Associate Laboratory University of Minho University Institute of Health Sciences (IUCS) CESPU

The aim of the present study was to perform a detailed morphological analysis of an injectable platelet rich fibrin after combination with two different particulate hydroxyapatite-based granules, a porous zirconia block, and laser-textured zirconia or titanium surfaces. Blood samples were harvested from three participants to prepare the flowable injectable PRF in contact or not with particulate hydroxyapatite (Hap), bone mineral granules (DBBM), porous zirconia blocks, laser-textured titanium or zirconia surfaces. Optical and scanning electron microscopy (SEM) were used to evaluate the fibrin network density, fibrin fibers’ diameter, blood cells, and the interaction of PRF with the biomaterials. Histomorphometry of the flowable PRF was also performed using the hematoxylin–eosin staining protocol. Specimens were independently evaluated by two blinded and well-trained researchers in histomorphometry and microscopy. Particulate Hap and DBBM shown different morphological aspects by SEM analyses since DBBM revealed macro- and micro-scale pores while Hap revealed a dense structure. Hydroxyapatite and DBBM granules were entirely embedded by the fibrin-network in the presence of leukocytes and blood platelets. The zirconia porous structured was filled with PRF and its components. Also, the laser-structured zirconia or implant surfaces were entirely coated with the PRF fibrin network embedding leukocytes and blood platelets. Laser-textured titanium surfaces revealed macro- and micro-scale irregularities that increase the surface area and retention of the injectable PRF. Histomorphometric analyses revealed complementary details on the distribution of lymphocytes, red blood cells, and fibrin associated with platelet aggregation. The flowing and viscosity of an injectable platelet rich fibrin provided an agglomeration of synthetic or xenogeneic particulate bone substitutes and the coating of porous zirconia and textured implant surfaces as inspected by scanning electron microsc

关键词： Bone healing Bone substitutes Histology Morphology Platelet-rich fibrin

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MgAl2O4 foams obtained by combustion synthesis

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Chemical engineering Transactions 2015年 43卷 1801-1806页

作者： Moraes, Graziela G. Pozzobom, Ida E.F. Fernandes, Celso P. Novaes De Oliveira, Antonio P. Graduate Program in Materials Science and Engineering - PGMAT Laboratory of Glass-Ceramic Materials - VITROCER Federal University of Santa Catarina - UFSC Florianópolis - SC88040 900 Brazil

ISBN: (纸本)9788895608341

This work aims to study magnesium aluminate (MgAl2O4) ceramic foams obtained by combustion synthesis in solution without the need of surfactants to stabilize *** ceramic suspension containing acetone (75 wt%), calcined powder (25 wt%) and a mixture of glycerine (80 % blonde glycerine and 20 % crude glycerine) in the fraction of 100 % with respect to solids was prepared in an alumina ball mill, for 60 min. Subsequently, the suspension was heated at 40 °C, for 30 min, until it became rigid. In order to promote foaming, the suspension was heated to 70 °C and then the following substances were added to it: 2.5 wt% distilled water, 25 wt% Al(NO3)3.9H2O), 12.5 wt% (Mg(NO3)2.6H2O) and 0.625 wt% of a glycerine mixture (80 % blonde glycerine and 20% crude glycerine). After additions the suspension was stirred for 5 min at 950 rpm in a mixer. The resulting foams were dried at 40 °C, for 24 h, in a muffle and fired in two steps, i.e., heating at 0.5 °C/min up to 600 °C/120 min and at 5 °C/min up to 1600 °C/120 *** obtained materials were characterized by SEM,TEM and from tomographic images. The results showed that the obtained magnesium aluminate foams have a high porosity (97 %), a high connectivity and pore sizes (diameters) between 30 and 1200 μm. Copyright © 2015, AIDIC ServiziS.r.l.

关键词： Pore size

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Production and characterisation of ceramic foams from industrial solid waste

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Chemical engineering Transactions 2015年 43卷 1783-1788页

作者： Zilli, Marina Arcaro, Sabrina Cesconeto, Francielly R. De Oliveira Maia, Bianca G. Pereira, Fabiano R. Novaes De Oliveira, Antonio P. Graduate Program in Materials Science and Engineering - PGMAT Laboratory of Glass-Ceramic Materials - VITROCER Federal University of Santa Catarina - UFSC Florianópolis-SC88040-900 Brazil

ISBN: (纸本)9788895608341

This work has as objective to produce and to characterize ceramic foams from glass bottles, sludge from sewage treatment station and graphite (0 - 10 wt%) as a foaming agent. Different compositions were formulated and prepared to obtain materials with controlled porosity for applications where thermal insulation is the main requirement. The raw materials of the prepared compositions were mixed and uniaxially pressed at 40 MPa. Subsequently, the prepared samples were dried and fired at different temperatures (800 - 950 °C) for 30 minutes, respectively. The raw materials and obtained ceramic foams were characterized in terms of their chemical, morphological, thermal and mechanical properties. The results showed that it is possible to produce ceramic foams for thermal insulation with optimized compositions containing 90 vol% glass and 10 vol% sludge with addition of 10 wt% graphite. The ceramic foams showed porosities between 40 and 70 %, thermal conductivity from 0.101 to 0.175 W/mK and compressive strength between 6.4 and 12.5 MPa. Copyright © 2015, AIDIC Servizi S.r.l.

关键词： Thermal insulation

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Production and characterisation of glass foams for thermal insulation

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Chemical engineering Transactions 2015年 43卷 1777-1782页

作者： Dias, Gabriella M.V. Arcaro, Sabrina Cesconeto, Francielly R. De Oliveira Maia, Bianca G. Pereira, Fabiano R. Novaes De Oliveira, Antonio P. Graduate Program in Materials Science and Engineering - PGMAT Laboratory of Glass-Ceramic Materials - VITROCER Federal University of Santa Catarina - UFSC Florianópolis-SC88040-900 Brazil

ISBN: (纸本)9788895608341

In this work, glass compositions from glass bottles with different colours and graphite (2 - 12 vol%) as the pore-forming agent were prepared for the production of materials with controlled porosity for applications where thermal and acoustic insulations are main technical requirements. The formulated compositions were, in a later stage, uniaxially pressed (40 MPa) and fired at different temperatures (800 - 950 °C) and cycles with holding times between 15 and 120 minutes. The results showed that it is possible to produce glass foams for thermal insulation from optimized compositions containing 90 vol% glass and 10 vol% graphite, fired between 800 and 950 °C for 30 minutes, which showed porosities between 53 and 76 %, with thermal conductivities between 0.16 and 0.08 W/mK and compressive strength between 20 and 4.6 MPa. The obtained glass foams are strong candidates for applications requiring thermal insulation with suitable combination of thermal conductivity, porosity and mechanical strength. Copyright © 2015, AIDIC Servizi S.r.l.

关键词： Thermal insulation

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Controlling the sliding motion of cyclodextrins in the polyrotaxane of PEI-b-PEG-b-PEI copolymer

Controlling the sliding motion of cyclodextrins in the polyr...

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54th SPSJ Annual Meeting 2005

作者： Choi, Hak Soo Yamamoto, Kaori Lee, Sang Cheon Ooya, Tooru Yui, Nobuhiko School of Materials Science Japan Advanced Institute of Science and Technology 1-1 Asahidai Nomi Ishikawa 923-1292 Japan 21St Century COE Program Japan Advanced Institute of Science and Technology 1-1 Asahidai Nomi Ishikawa 923-1292 Japan Korea Institute of Ceramic Engineering and Technology 233-5 Gasan Guemcheon Seoul 153-801 Korea Republic of

Our aim here is to synthesize a water-soluble polyrotaxane for examining the pH-responsive movement of CDs along the chains of PEI-b-PEG-b-PEI copolymer. Since the components of the polyrotaxane are held together by noncovalent bonds, the mobility of the cyclic compound could be controlled at the molecular level in aqueous solutions.

关键词： Oligomers

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Magnetic correlations induced by magnetic field and temperature in Gd5Ge4

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Physical Review B 2002年第21期65卷 214427-214427页

作者： E. M. Levin K. A. Gschneidner, Jr. V. K. Pecharsky Metal and Ceramic Sciences Program Ames Laboratory (U.S. DOE) Ames Iowa 50011-3020 Materials Science and Engineering Department Iowa State University Ames Iowa 50011-3114

Several unexpected and intriguing magnetic phenomena have been observed in the Gd5Ge4 compound. First, below ∼130 K, Gd5Ge4 is antiferromagnetic in a zero magnetic field, but it can be transformed into the ferromagnetic state both irreversibly (below 10 K) and reversibly (above 20 K) depending on the magnitude of the applied magnetic field, the temperature, and the direction of their changes. Second, the irreversible antiferromagnetic→ferromagnetic transformation at 4.3 K is abrupt in magnetic fields exceeding 18 kOe, but it is sluggish in lower (∼17 kOe) magnetic fields. Third, both the antiferromagnetic and ferromagnetic Gd5Ge4 phases may coexist indefinitely under certain combinations of the magnetic field and temperature. It is likely that the unusual magnetic correlations in Gd5Ge4 arise due to strongly anisotropic exchange interactions as a result of variations in the chemical bonding in this naturally layered, and therefore, low-dimensional magnetic system.

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