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Constrained Drying of an Aqueous Yttria‐Stabilized Zirconia Slurry on a Substrate II: Binary Particle Slurry
Author(s) -
Lan Weihua,
Xiao Ping
Publication year - 2007
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.1551-2916.2007.01839.x
Subject(s) - slurry , materials science , particle (ecology) , composite material , particle size , coating , microstructure , substrate (aquarium) , ultimate tensile strength , viscosity , shrinkage , chemical engineering , metallurgy , oceanography , engineering , geology
Binary‐sized particle slurries (binary slurries) prepared by mixing micro‐particles and electrostatically stabilized nano‐particle slurries (nano‐slurries) were cast onto metal substrates to form wet coatings and the drying process was studied. The highly charged nano‐particles were found to deposit on the surface of the micro‐particles, resulting in a decrease in the viscosity of the binary slurry. The drying kinetics were classified as an initial constant rate period (CRP), followed by a falling rate period. In the early stage of CRP, the movement of micro‐particles induced coating shrinkage and tensile stresses developed due to the constraint of the substrate. Thereafter, the nano‐slurry continued to dry and shrink around the static micro‐particles without further coating shrinkage, but with an increase in the stress. The addition of micro‐particles reduced the level of the maximum stress and prevented crack formation during drying. The microstructure of green coatings shows the presence of nano‐particles between micro‐particles that cement the micro‐particles together.