Ceramic composites of the Al2O3-ZrO2 type obtained by the Direct Coagulation Casting Method

Anita Grzeda ,  Mikolaj Szafran 

Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, Warszawa 00-664, Poland

Abstract


The Direct Coagulation Casting (DCC) is a new and very interesting method of molding samples from ceramic casting slips of high concentration of the solid phase. It consists in concentrating the casting slip via internal slow change of pH round each ceramic powder particle, which causes changes in the electrostatic repulsion forces of double electric layers in favor of the Van der Waals attraction forces.
The role of enzymes in the DCC process consists in the decomposition of an appropriately selected substance which results in slow liberation over the whole volume of molecules changing the pH or also in the synthesis of salts modifying the double electric layer.
The 15 nm grain size nanopowder of zirconia used in the study was purchased from "CEREL" Boguchwała as was the "gel", the hydrated mixture of zirconia salts, which produces nZrO2 upon calcination. The paper discusses the differences between the properties of Al2O3 grains modified with the additions of: a) zirconia nanopowder, b) the "gel", and c) zirconia powder of grain size comparable to that of Al2O3. The addition of zirconia is intended to increase the fracture toughness of alumina. It is assumed that the addition of the nanopowder of zirconia, due to its small particle size, may form nanolayers around the grains of Al2O3 or fill the spaces between them.
The results of using the urease-urea system and the properties of ceramic casting slips, green samples and after sintering with aluminium oxide, Al2O3-ZrO2, and Al2O3-nZrO2 composites are presented in the paper.
The obtained results of studies show a considerable probability of obtaining on the future Al2O3-ZrO2 and Al2O3-nZrO2 composites.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: http://science24.com/paper/895 must be provided.

 

Related papers
  1. Doping of ZnO nanopowders with Mn, Ni and Cr In an ultrasound and microwave driver hydrothermal reaction
  2. Doping of ZnO nanopowders with Mn and Cr in an ultrasound and microwave driven hydrothermal reaction
  3. Time-resolved luminescence of nanostructured ZnO

Presentation: poster at E-MRS Fall Meeting 2003, Symposium F, by Anita Grzeda
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-27 13:22
Revised:   2009-06-08 12:55
Google
 
Web science24.com
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine