Premium
Drying Behavior of Colloidal Silica Gels
Author(s) -
Simpkins Peter G.,
Johnson David W.,
Fleming Debra A.
Publication year - 1989
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.1151-2916.1989.tb05984.x
Subject(s) - materials science , relative humidity , shrinkage , isothermal process , colloidal silica , composite material , colloid , humidity , cracking , evaporation , viscoelasticity , surface tension , chemical engineering , meteorology , thermodynamics , coating , physics , engineering
Observations of the drying behavior of thick‐wall colloidal silica gel structures are reported. Various techniques are examined to prevent cracking during the drying of these highstrain viscoelastic materials. Experiments are described which illustrate the effect of relative humidity on the drying rate and on the shrinkage of various samples under isothermal conditions. Surface temperature measurements indicate that evaporation occurs at approximately the wet‐bulb temperature of the surrounding atmosphere. Acoustic detection of the internal strain activity during drying leads to the conclusion that control of the sol‐gel surface tension in the material preparation is crucial to reducing the interior stresses.