Structure formation of hot pressed Al2O3 powders under the alternating electric current: experimental observations

¹Materials and Manufacturing Technology for Transport Applying Products Dept., Ukrainian State University of Railway Transport, pl. Feyerbaha 7, Kharkov, 61010, Ukraine

²Information Technology & Systems KGM Dept., National Technical University "Kharkov Polytechnic Institute", Frunze Street 21, Kharkov, 61002, Ukraine

³Faculty of Mechanical Engineering, Kazimierz Pulaski University of Technology and Humanities in Radom, Krasickiego Street 54, Radom, 26-600, Poland

Adv. Mater. Lett., 2017, 8 (10), pp 945-949

DOI: 10.5185/amlett.2017.1718

Publication Date (Web): Jul 22, 2017

Copyright © IAAM-VBRI Press

E-mail: m.rucki@uthrad.pl

Abstract

The paper presents the results of investigations on hot pressure sintering under the alternating current. The powders of different grain sizes were used for the sintering to investigate the impact of the powder on the final sintered structure and relative density. The additional experiments were focused on the kinetics of the Al₂O₃ nanopowders sintering. They confirmed that the time of the process duration is dependent on the temperature and the applied pressure. However, compared to the powders of tungsten monocarbide, it depends on the temperature rise speed in rather small degree. Discussion of the results pointed out that the obtained data, both theoretical and experimental one, confirmed possibility that during the sintering process the dislocations might appear and spread. It seemed reasonable to assume that in the low voltage regime the activated sliding with diffusion accommodation prevails, while in the high voltage regime the dislocation creep does.

Keywords

Nanopowders, sintering, ceramics, compaction.