Surface reactivity and electrophoretic deposition of ZrO2–MgO mechanical mixture
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Electrophoretic deposition (EPD) is a precision technique useful for obtaining high quality ceramic bodies with controlled dimensions and smooth coatings. The electrophoretic deposition rate is highly dependent on the surface chemistry of the powders, especially when dealing with multi-component systems. The objective of this work is to study the surface reactivity of both ZrO2 and MgO in ethanol suspension to provide experimental benchmarks to control EPD of a ZrO2–3 wt% MgO mechanical mixture (Z3M) in ethanol. Infrared spectroscopy (FTIR) showed that ZrO2 surface spontaneously reacts with ethanol, generating negative electrophoretic mobility of the particles (−0.07 × 10−8 V−1 s−1) measured by Electroacoustic Sonic Amplitude (ESA). MgO surface also spontaneously reacted with ethanol, but a positive electrophoretic mobility was observed in this case (0.26 × 10−8 V−1 s−1). Scanning Electron Microscopy of Z3M dried from ethanol suspension showed that MgO particles were located around the ZrO2 particles, forming composite agglomerates, probably due to the electrostatic attraction between MgO and ZrO2 particles. Homogeneous deposits could be obtained from EPD of Z3M ethanol suspensions. Mercury intrusion porosimetry showed that the ZrO2–MgO green deposited bodies using different voltages had similar pores diameters distributions, indicating that the ZrO2–MgO agglomerates are not affected by the increasing deposition rates.
KeywordsApplied Voltage Electrophoretic Mobility Ethoxide Mercury Intrusion Porosimetry Electrophoretic Deposition
The authors wish to thank FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) processes 05/53241-9 and 05/55335-0; and CAPES (Coordenação do Aperfeiçoamento de Pessoal de Nível Superior) for the financial support.
- 1.Richerson DW (1992) Modern ceramic engineering: properties, processing, and use in designGoogle Scholar
- 2.Chiang Y-M, Birnie D, Kingery WD (1997) Physical ceramics – principles for ceramic science and engineering. John Wiley & Sibs Inc., New YorkGoogle Scholar
- 3.Persson M (1994) In: Pugh RJ, Bergstrom L (eds) Surface and colloid chemistry in advanced ceramic processing. Marcell Decker, New YorkGoogle Scholar
- 4.Hirata Y, Numaguchi N, Shih WH (1999) In: Novel synthesis and processing of ceramics. p 127Google Scholar
- 10.Hadraba H, Maca K, Cihlar J (2004) Ceram Int 30:853Google Scholar