Influence of processing parameters on the behaviour of thick bilayers (Cer/Cer) performed by powder processing: Dilatometry without contact

As multilayer materials are essential to today׳s industry, solid state co-sintering of a thick bilayer was investigated. This paper focuses on the possible effects of processing on shrinkage measured at different levels of each material during thermal treatment, and on the quality of the bimaterial. Suitable in situ monitoring non-contact devices were developed both for conventional and microwave furnaces. The pictures taken with the apparatus quantified the shrinkage, and thus any mismatch strain between layers was then able to be calculated. Moreover, the appearance of debonding or even cracks can be detected. With this approach, the influence of co-pressing and co-sintering can be underlined. In powder processing, based on the information gathered via the camera on the deformations in the bilayer as well as any damages with the SEM, it was revealed that when compromising between the mismatch strain and the densification, it is possible to obtain a crackless thick bilayer material.