Deposition of zirconia sols on woven fibre preforms using a dip-coating technique

The technique of depositing zirconia coatings onto woven fibre mats has bee n investigated in detail. The application of a coating to the fibre is esse ntially one of the easiest methods of providing a fibre-matrix interface wi th desired properties. Such coatings can act as reaction barriers or as fib re-matrix debond interfaces. This particular coating method, which is the d ip-coating of fibre tows in zirconia sols? does not require sophisticated a pparatus and, therefore, has great potential as a standard coating techniqu e for use with woven fibre systems. In this work, an "in-house" produced zi rconia sol, synthesised using hydrothermal processing, has been found to be the most successful coating material. Both alumina and alumina-silica wove n fibre mats were used as the substrate materials. It has been shown that t he zirconia sol employed can be deposited successfully in a single coating step, as a thin (1-2 mu m) coating with minimal bridging of the fibre mats. The critical coating parameters when using this dip-coating technique have been discussed in detail. (C) 2000 Elsevier Science Ltd. All rights reserv ed.