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Surface Modification Mechanism of Stearic Acid to Zirconia Powders Induced by Ball Milling for Water‐Based Injection Molding
Author(s) -
Liu Wei,
Xie Zhipeng,
Yang Xianfeng,
Wu Yin,
Jia Cui,
Bo Tiezhu,
Wang Linlin
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04475.x
Subject(s) - stearic acid , cubic zirconia , ball mill , materials science , molding (decorative) , surface modification , composite material , chemical engineering , mechanism (biology) , ceramic , engineering , philosophy , epistemology
In conventional process of ceramic injection molding, wax‐based binders could only be removed by thermal or organic solvent debinding. Recently, water solvent debinding has appeared as a good alternative owing to its high efficiency and environmental friendliness. In present work, we have demonstrated the surface modification mechanism of stearic acid (SA) to zirconia powders induced by a prior ball‐milling treatment before the blending process. Layers of SA with various thicknesses coated around the zirconia powders have been achieved with different amount of SA after the treatment, agreeing well with the theoretically calculated values. The coating is disclosed to be an esterification occurring between the carboxyl group of SA and hydroxyl group of zirconia surface. It plays an important role in limiting agglomeration of ceramic powders and changing the nature of powder surface from hydrophilicity to hydrophobicity, which decreases the shear viscosity of the feedstock and makes the water‐debound compact process‐compatible with few phase separation. In addition, a significantly faster water‐debinding rate was obtained.