title: Electric current activated/assisted sintering (ECAS): a review of patents 1906-2008.
abstract: The electric current activated/assisted sintering (ECAS) is an ever growing class of versatile techniques for sintering particulate materials. Despite the tremendous advances over the last two decades inECASed materials and products there is a lack of comprehensive reviews onECASapparatuses and methods. This paper fills the gap by tracing the progress ofECAStechnology from 1906 to 2008 and surveys 642ECASpatents published over more than a century. It is found that theECAStechnology was pioneered by Bloxam (1906 GB Patent No. 9020) who developed the first resistive sintering apparatus. The patents were searched by keywords or by cross-links and were withdrawn from the Japanese Patent Office (342 patents), the United States Patent and Trademark Office (175 patents), the Chinese State Intellectual Property Office of P.R.C. (69 patents) and the World Intellectual Property Organization (12 patents). A subset of 119 (out of 642)ECASpatents on methods and apparatuses was selected and described in detail with respect to their fundamental concepts, physical principles and importance in either presentECASapparatuses or futureECAStechnologies for enhancing efficiency, reliability, repeatability, controllability and productivity. The paper is divided into two parts, the first deals with the basic concepts, features and definitions ofbasic ECASand the second analyzes theauxiliary devices/peripherals. Thebasic ECASis classified with reference to discharge time (fastandultrafast ECAS). The fundamental principles and definitions ofECASare outlined in accordance with the scientific and patent literature.
authors.affiliation: World Premier International Research Center Initiative (WPI Initiative) on Materials Nanoarchitechtonics (MANA), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan; Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan; Nano Ceramics Center, Fine Particle Processing Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Grasso
authors.affiliation: World Premier International Research Center Initiative (WPI Initiative) on Materials Nanoarchitechtonics (MANA), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan; Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan; Nano Ceramics Center, Fine Particle Processing Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Sakka
authors.affiliation: Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maizza
keywords: electric assisted sintering; electric discharge compaction; field activated/assisted sintering technique; patents; pulsed electric current sintering; spark plasma sintering