Prediction and Explanation of Aging Shrinkage in Tape-Cast Ceramic Green Sheets

A simple test to predict linear shrinkage of tape-cast green sheets as a function of time was developed. Shrinkage was found to correlate inversely with the amount of organic phase bound to ceramic particle surfaces. The test was developed for alumina green tapes with acrylic binder. The correlation was found to be independent of the medium used for the two slurry systems evaluated, water and toluene/ethanol. Treatments developed to dimensionally stabilize green sheets reduced shrinkage after 35 days of aging to less than 0.15%. Stabilization treatments involved heating and/or polymer swelling which facilitated the binding of organic phase to alumina particles, causing the tape to be in a more relaxed state.