A non-destructive method to assess delamination of ceramic tiles

Delamination is a typical defect of ceramic tiles. It originates from the presence of trapped air during pressing, and elastic recovery of the pressed material, which prevents the consolidation of the pressed material. Although delamination greatly reduces the quality of the final product, standard tests for ceramic tiles are not currently available. In this work the problem of detecting delamination of green and fired ceramic tiles is approached by using ultrasonic pulse velocity measurement, a non-destructive technique normally used to assess concrete structures and the density of ceramic tiles. It was assumed that an increase in travel time for a given thickness (i.e., decrease in travel velocity) would indicate the presence of delamination, as the sound wave has to travels around the flat pore. The problems connected with measurement uncertainty and repeatability are discussed in the paper, in particular concerning the standardisation of the measurement. (c) 2006 Elsevier Ltd. All rights reserved.