High critical temperature superconducting (HTcS) bulk ceramics with the high values of critical current densities (Jc) necessary for practical applications, are only achieved through careful control of the material microstructure. Consequently, many stages in the production of HTcSs are extremely time consuming; often taking a number of days to proceed to completion, and usually requiring precise control of sample temperature.
The volumetric nature of microwave heating will clearly have an impact on the processing of large quantities of these materials, particularly when it is balanced with the simultaneous application of radiant heating. In this way, the production of thermal gradients can be avoided, even when relatively fast heating rates (for these materials) are used.
Perhaps more interesting, is the possibility of non-thermal microwave effects (due to the presence of an electric field) enhancing the processing times and even the material properties of HTcSs.
This work assesses the impact of microwave-assisted processing on a number of stages involved in the production of bulk pieces of Bi-2212 and Y-123 based superconductors, and demonstrates quite clearly that non-thermal as well as thermal microwave effects are relevant to these materials.