CERAMIC ARTICLES AND THEIR MANUFACTURE

摘要

A slip composition for use in a slip casting process comprises an aqueous suspension of a kaolin clay and other optional ingredients. Green bodies prepared from the slip composition have good cracking resistance. The slip composition has a casting rate (CR) under a standard test method, and a resultant test green body has a cracking tolerance number at the critical moisture content (CTNcmc) under a standard test method. The CTNCme and CR obey the relationship CTNcmc >= 29 - 8 1neCR where lneCR is the natural logarithm of the casting rate expressed in mm<2>/min. A corresponding relationship between the CTNcmc and the permeability of the slip composition under a standard test method may alternatively be used. The invention also enables the cracking resistance of green bodies prepared from slip compositions to be improved, and enables a method of testing a slip composition for cracking resistance. These methods use the same relationship as an indicator of good cracking resistance.