Development of a prototype of sintering furnace ultrafast assisted by the electrical field

Abstract

The FORTELAB Industry Electric Ovens Ltd was founded in 09/08/2005 in Sao Carlos SP in order to develop special ovens for laboratories and industries. This initiative was one of the motivations the observation that there is a shortage in the Brazilian industry of companies that specialize in certain types of oven and other electrical equipment. Added to this, it was noted that internal and external demand for some types of products has increased rapidly. Among the special ovens that we believe are strategic for the development of advanced research and the Brazilian industrial sector, has gained prominence the electric field work carried out in ovens assembled in the laboratory where it is applied inside through a green ceramic body using a pair electrodes. This sintering method called flash sintering has been gaining importance in recent years and was first reported by Cologna and coworkers in 2010. In this technique, low electromagnetic field values and a direct current (dc) or alternating current (AC). They are applied during the sintering of a ceramic part. As a result, in a matter of minutes, high densification is obtained with low grain growth of this ceramic material. In this method, the sintering is performed depending on the applied voltage. Any time as the sintering temperature required to achieve high densification of the ceramic material are substantially reduced. These modifications allow, for example, sintering of stabilized zirconia 3% yttria at temperatures below 850 ° C in a few seconds. The main advantage of this technique is to reduce the sintering time and temperature, which is a very important factor in terms of energy and production economy. It is noteworthy that, as a method of very recent unconventional sintering, there is no flash sintering equipment that can be bought on the domestic and international markets. In this context, the objective of this project is focused on the development of a prototype of a high temperature tube furnace with application of pressure (mechanical axial pressure), electric field (with continuous and / or alternating current) can be used with inert atmosphere for sintering ultra fast ceramic materials: flash sintering. As a result, in a matter of minutes, high densification is obtained with low grain growth of this ceramic material. Thus, the development of a sintering furnace assisted by the electromagnetic field is a promising alternative to sintering of ceramic materials using up to 70% less energy during the sintering process. (AU)