Surface characterization of plasma sprayed oxide materials: estimation of surface acidity using mass titration

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• 作者：Harju ; Mika ; Lev&auml ; nen ; Erkki ; M&auml ; ntyl&auml ; Tapio
• 关键词：Plasma spraying ; Mass titration ; Point of zero charge ; PZC
• 刊名：Journal of Colloid and Interface Science
• 出版年：2004
• 期刊代码：125_00219797
• 类别：ch
• 出版时间：August 15, 2004
• 卷：276
• 期：2
• 页码：346-353
• 文件大小：426 K

摘要

The aim of this study was to characterize the influence of plasma spraying on the point of zero charge (PZC) of Al₂O₃-, Cr₂O₃- and TiO₂-based materials. PZC is one of the most important parameter, which describes the acidity of oxide material in aqueous environments. PZC values of several plasma sprayed oxides were determined using mass titration method. Studies were performed for initial spray powders and plasma sprayed coating materials. In addition, mass titration experiments were performed for water-washed and nonwashed samples. It was found that mass titration is a suitable method to estimate the surface acidity of relatively coarse sample powders. It was found for most of the studied materials that the limiting pH values (assumed to be close PZC) were close to those reported in literature for the PZC values of traditionally manufactured oxide materials. On the other hand, mass titration curves of some oxide samples showed unexpected deviation in curve shapes and limiting pH. These deviations were probably due to selective dissolution of sample contaminations or sample material.