14. Manufacturing of Doped Glasses Using Reactive Electrophoretic Deposition (REPD)
- William M. Mullins,
- Andrew Wereszczak and
- Egar Lara-Curzio
Published Online: 26 MAR 2008
Copyright © 2007 The American Ceramic Society
Synthesis and Processing of Nanostructured Materials: Ceramic Engineering and Science Proceedings, Volume 27, Issue 8
How to Cite
Jung, D., Tabellion, J. and Clasen, R. (2008) Manufacturing of Doped Glasses Using Reactive Electrophoretic Deposition (REPD), in Synthesis and Processing of Nanostructured Materials: Ceramic Engineering and Science Proceedings, Volume 27, Issue 8 (eds W. M. Mullins, A. Wereszczak and E. Lara-Curzio), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291375.ch14
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2007
Print ISBN: 9780470080511
Online ISBN: 9780470291375
Doped glasses can be manufactured by means of gas infiltration, soaking of green bodies, by using powder mixtures or by melting. The melting point of silica glass is 2100 °C and most dopants evaporate at temperatures in this range. Because the sintering temperature of silica glass is about 700 °C lower then melting point, dopants, that would evaporate during the melting process, can be used. But it is difficult to achieve homogeneous green bodies by using powder mixtures because separation occurs as the particles have different sizes and densities. In case of the soaking method, during the drying process a surface segregation of the salt ions leads to samples with an inhomogeneous distribution. A promising method to manufacture homogeneous silica green bodies is the electrophoretic deposition (EPD)1. In the first approximation the mobility of the particles is independent of their size2.
A modification of the EPD, by adding salts to the suspension, leads to reactive electrophoretic deposition (REPD). By varying the amount of added salts to the suspension, the dissolved ions modify the occupancy of particle surfaces and the composition of the cloud of ions. The adsorbed ions can be co-deposited with the particles leading to a very homogeneously doped green body. It is tested first for a suspension of SiO2 that contained different amounts of boric acid and cobalt chloride. It is shown that the green bodies doped with boric acid can be sintered at lower temperatures compared to undoped ones. However, the sintering temperature depends on the amount of boric acid added to the suspension before.