Electrophoretic deposition of ZrO2–Y2O3: a bi-component study concerning self-assemblies
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There are many industrial advantages of using mechanical multi-oxides mixtures to obtain ceramic parts by electrophoretic deposition (EPD). This is mainly because one could avoid complex chemical synthesis routes to achieve a desirable composition. However, EPD of these suspensions is not an easy task as well since many different surfaces are present, leading to unexpected suspension behavior. The particles surface potentials and interactions can, however, be predicted by an extension of the DLVO theory. Using this theory, one can control the suspension properties and particles distribution. The objective of this work was to apply the colloidal chemistry theories to promote the formation of a heterocoagulation between ZrO2 and Y2O3 particles in ethanol suspension to achieve a suitable condition for EPD. After identifying a condition where those particles had opposite surface charges and adequate relative sizes, heterocoagulation was observed at operational pH 7.5, generating an organized agglomerate with ZrO2 particles surrounding Y2O3, with a net zeta potential of −16.6 mV. Since the agglomerates were stable, EPD could be carried out and homogeneous deposits were obtained. The deposited bodies were sintered at 1600 °C for 4 h and partially stabilized ZrO2 could be obtained without traces of Y2O3 second phases.
KeywordsY2O3 Solid Loading Electrophoretic Deposition Total Potential Hamaker Constant
The authors wish to thank FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) Procs. 05/53241-9 and 05/55335-0, and CAPES (Coordenação do Aperfeiçoamento de Pessoal de Nível Superior) for the financial support.
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