Papers by Keyword: Ceramic

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Authors: Kotoji Ando, Yasuharu Shirai, M. Nakatani, Y. Kobayashi, S. Sato
Authors: Anke Bernstein, Renate Gildenhaar, Georg Berger, Hermann O. Mayr
Abstract: Bioactive ceramics such as β-tricalcium phosphate (β-TCP) promote and enhance biological fixation. Ceramics with a porous interconnected structure are suited for facilitation of bony ingrowth. An interconnected pore system with pore diameters in excess of 100 µm is required for cell penetration, tissue ingrowth, vascularization and nutrient delivery to the centre of the regenerating tissue. Human osteoblasts were cultured on the surface of a ceramic. In an in-vivo study, β-TCP samples with a porous interconnected structure were implanted into the femur of sheep and then investigated 6 weeks after operation. Histological analysis was performed on the area surrounding the implant. An indentation test was performed to complete failure of the bone/ceramic compound. Linear load, peak load and stiffness were recorded. All cylinders were found to be biocompatible and osteoconductive. Bone was more abundant in the outer ring than in the rest of the cylinder. The ceramic/bone compound was of low mechanical grade.
Authors: Inga Narkevica, Aigars Reinis, Lauma Bugovecka, Ingus Skadins, Errj Sansonetti, Juta Kroica, Jurijs Ozolins
Abstract: Biomaterials used in bone repair must satisfy certain criteria in order to perform without undesirable immunological response. They must be biocompatible and should inhibit bacteria adhesion on the surface, that could led to strong inflammatory process and implant failure. Our study reveals a synergistic effect on bioactivity and bacteriostasis effect of the TiO2 ceramics with different surface properties and provides insight into the design of better biomedical implant surfaces. The results show that UV light irradiation has great impact on hidrophilicity of TiO2 ceramics, but little effect on the sample bacteriostatic effect and bioactivity. TiO2 ceramic samples showed no or very low bacterial adhesion. Nevertheless, in vitro bioactivity showed TiO2 ceramic that was thermally treated at lower temperature. Thus for bone repair it’s suggested to use TiO2 ceramic sintered at lower temperature in order to provide bioactivity with bacterostatic effect and use UV-light irradiation to improve hidrophilicity.
Authors: Pierre Layrolle, Serge Baroth, Eric Goyenvalle, Eric Aguado, Françoise Moreau, G. Daculsi
Abstract: An hydrated putty was prepared by mixing submicron particles, rounded particles and granules of Biphasic Calcium Phosphate (BCP) ceramics composed of HA and β-TCP phases. The material filled entirely critical sized defects in the femoral epiphysis of NZW rabbits. After 3, 6 and 12 weeks, histology revealed that submicron particles were rapidly degraded by multinucleated TRAP-positive cells. This osteoclastic resorption stimulated bone ingrowth while the large BCP particles served as scaffold supporting bone healing by osteoconduction.
Authors: David Huson, Stephen Hoskins
Abstract: The Centre for Fine Print Research at the University of the West of England has over five years experience in the 3D printing of ceramic materials. The first project undertaken was to investigate the use of 3D technologies for artists and resulted in the development of a patented ceramic body suitable for use in Z Corporation 3D printers. After bisque firing this material can be further processed using conventional glazing and decorating techniques. A follow on project has resulted in a modified ceramic body and the development of firing supports to enable thin section ceramic tableware to be produced for ceramic industry concept modelling and short run or one-off pieces for artists and designers. This paper will detail the progress of the research and will explain by using case studies and examples of collaboration with a leading UK pottery manufacturer, individual artists and designers how this novel technique can be utilised to form shapes and forms difficult or impossible to realise by conventional forming methods. The potential of how the ability to form ceramic objects with complex internal structures could be beneficial to more specialist ceramics industries will also be explored.
Authors: Yan Fang Shen, Wan Song, Xin Yu Cui, Tian Ying Xiong
Abstract: TiO2 is a promising photocatalyst with great potential for environment purification and energy conversion. TiO2 coatings have more advantages over powders in practical use. Cold spraying is an ideal technique to fabricate TiO2 coatings because of its low heat input compared with thermal sparing which may induce undesirable phase transformation from anatase to rutile. The paper will give a short introduction on recent development of TiO2 coatings by cold spraying. Then, the factors affecting the quality of coating should be analyzed. And finally, the bonding mechanism of cold sprayed TiO2 coating on metal substrates will also be proposed.
Authors: Sebastian Stanislawek, Andrzej Morka, Tadeusz Niezgoda
Abstract: The paper presents a numerical study of a double layer composite panels impacted by a AP (Armor Piercing) 51WC projectile. The standard panel is built with aluminum and Al2O3 ceramic continuum layers while the studied model consists of the same aluminum plate but the front one is built with a set of hexagonal ceramic bars. The bar width and the impact position influence on the ballistic resistance are analyzed and compared with the reference solution. The problem has been solved with the usage of the modeling and simulation methods as well as finite elements method implemented in LS-DYNA software. Space discretization for each option was built by three dimension elements guarantying satisfying accuracy of the calculations. For material behavior simulation specific models including the influence of the strain rate and temperature changes were considered. Projectile Tungsten Curbide and aluminum plate material were described by Johnson-Cook model and ceramic target by Johnson-Holmquist model. In the studied panels the area surrounding back edges was supported by a rigid wall. The obtained results show interesting properties of the examined structures considering their ballistic resistance. All tests has given clear results about ballistic protection panel response under WC projectile impact. Panels consisting of sets of hexagonal ceramic bars are slightly easier to penetrate, reference model is stronger by 19% for smaller bars and by only 7% for bigger rods. Despite this fact, the ceramic layer is much less susceptible to overall destruction what makes it more applicable for the armor usage. Furthermore, little influence of the projectile impact point and consequently a part of the bar which is first destroyed is proved.
Authors: Yu Ping Tong, Rui Zhu Zhang, Shun Bo Zhao, Chang Yong Li
Abstract: Well-dispersed fluorite Er2Zr2O7 nanocrystals have been successfully prepared by a convenient salt-assistant combustion method. The effects of calcinations temperature and salt category on the characteristics of the products were investigated by XRD and TEM. The thermal treatment temperature has an important effect on crystal size and lattice distortion of the nanocrystals. The experiment showed that the introduction of salt in the combustion synthesis process resulted in the formation of well-dispersed Er2Zr2O7 nanocrystals. The average size was 30 nm and was in agreement with the XRD result, which indicated that the nanocrystals were uniform in particle size distribution. Moreover, the possible formation process in the salt-assisted combustion synthesis was also analyzed.
Authors: Pius Bamidele Mogaji, Tamba Jamiru, Dawood Desai, Rotimi Sadiku
Abstract: Efforts at utilizing ceramic materials with their undeniably interesting range of properties in automobile manufacture, has persisted for many years. The corrosion resistance, the resistance to oxidation at high temperatures, the capacity of its resistance to wear and the low relative density of these materials make them especially attractive candidates for use in the automotive engine block production. The limitations of ceramics materials in the area of low fracture toughness can be assuaged by using various methods of grain and boundary size strengthening. This paper presents a critical survey of some of the existing materials used in the production of automotive engine block, the existing methods of toughening and strengthening of ceramic composite materials with emphasis on methodologies, strengths and weaknesses.
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