The conventional method of press followed by furnace sintering is now substituted by an electrical consolidation method. This allows joining in a single step the previous pressing/sintering processes, and, due to the promptness of the process, the use of controlled atmospheres is not necessary. The steps of magnetization, and eventual thermal treatments, can be carried out in the same container, without being necessary to manipulate the product.
Description of the technology
The object of this patent is a new method for permanent magnets production, mainly those containing rare earths in their composition. The manufacturing method substitutes the conventional press+sinter method by a quick consolidation technique, based on a FAST (Field Assisted Sintering Technique) process. The use of this technique simplifies the magnet manufacturing, and reduces the fabrication cost.
The main innovation of the described method is the way to consolidate the material in order to obtain the magnet. Field Assisted Sintering Techniques, as Electrical Resistance Sintering or Electrical Discharge Consolidation/Sintering, are techniques where the sintering process is carried out in a very quick way, even less than one second, therefore being possible not to use controlled atmospheres to avoid the material interaction with atmosphere. On the other hand, the technique allows obtaining magnets with the desired final geometry, the whole time of the process with the material in the same container.
Main advantages of its use
- The simplification of the consolidation process, and the possibility of finishing the magnetization without being necessary to manipulate the product, makes this method economically attractive.
- The use of thin dies during the FAST process allows the magnetization coil to be very near the powder, improving results.
- On the other hand, the process can produce very small parts with the final or very near the final desired shape, with a clear advantage on the field requiring these small near-net-shaped parts.
- Many electrical and electronic applications make use of permanent magnets, in many cases of small size, as those mainly aimed to produce with this manufacturing technique. Many sector are continuously using such devices in their products, and therefore, makers of such devices could be interested in the developed method.