Sintering activation by external electrical field

Field assisted sintering technique (FAST) is a non-conventional powder consolidation method in which densification is enhanced by the application of an electrical discharge combined with resistance heating and pressure. Interest in FAST is motivated by its ability to consolidate a large variety of powder materials to high densities in short times. Full densification of metal and ceramic powders has been achieved within minutes, with a reduced number of processing steps, no need for sintering aids and more flexibility in powder handling. Although the electrical discharge effects have not been completely elucidated, distinct surface effects created by micro-discharges have been noticed in FAST consolidated specimens such as atomically clean grain boundaries and new resistivity peaks in superconductors. On-going experimental and theoretical studies to provide more quantitative insight into the relevant. FAST mechanisms are presented. (C) 2000 Elsevier Science S.A. All rights reserved.