Papers by Keyword: Technical Ceramics

Abstract: The technical porcelain is usually obtained by mixing different raw materials, which are generally clay, kaolin, quartz, and a fluxing agent, in appropriate amounts. These porcelains are used in the production of electric and electronic devices for several applications, ranging from high and low power capacitors to low, medium, high and extra high voltage insulators. In this work, we studied technological properties of dielectric porcelain, obtained from raw materials found in large quantities and excellent quality in the Rio Grande do Norte state in Brazil. Test samples were produced by powder technology for two different compositions: composition A (20% clay, 28% kaolin, 32% feldspar and 20% quartz) and composition B (15% clay, 31% kaolin, 33% feldspar and 21% quartz), and sintered at temperatures, T1=1150°C, T2=1200°C, T3=1250°C, T4=1300°C and T5=1350°C with isotherms P1=0.5 hours, P2=1 hour, P3=1.5 hours and P4=2 hours. Then after sintered, the sample microstructure was characterized by scanning electron microscopy (SEM) and analysis of dielectric strength with direct and alternating voltage. The best results for electrical properties were obtained in temperature of 1250oC for composition A, and confirms the electrotechnical porcelain production feasibility.

Abstract: This paper assesses the moldability of press-powder with different fractional composition. Different types of defects that occur in ceramic materials due to insufficient or overpressure of molding of press powderare analyzed. Based on results of structural studies and evaluation of the physical properties of materials recommendations on the molding selection modes of press-powders with different fractional composition that provide the absence of defects in the compacts and obtaining quality dense ceramics are formulated.

Abstract: The development of open source 3D printers and the continuously growing utilization of ceramic compounds in the field of medicine among others, meet in the possibility to adapt these machines in a way to permit better controlling, high resolution, automatic, printing of scaffolds, spacers and other 3D parts not possible without this kind of machines and technology. Due to the large number of applications inside the field of medicine it is required a high capacity to create structures that can reach the needs in each case. Furthermore, the possibility to modify easily and quickly these structures as the tests are being done is also very interesting for investigation. These machines allow, thanks to its open source nature, these features and more as they are not closed to changes in order to meet the needs of its users. Therefore, the focus of the present work has been to materialize and improve a head extruder for Advanced Technical Ceramics Compounds. The tests undertaken and the results outcome demonstrate the feasibility of the technology for being applied in such mentioned cases as well as the improvement on the solutions (initial and improvements) for producing automatic casting.

Abstract: This paper attempts to shed light on why the stand alone microwave processing of technical ceramics, despite being one of the most popular field with respect to volume of research performed, is still struggling to achieve priority status with respect to commercialisation. To obtain some answers to this enigma and determine when microwaves should be used to process technical ceramics, three case studies are explored. The conclusion is that microwaves should be used to process technical ceramics when specific advantage can be taken of the intrinsic nature of microwave energy and not simply as an alternative energy source. In addition, it is concluded that from a commercialisation view point hybrid processing is often a better approach than the use of pure microwaves.