Joining of ceramic oxides by liquid wetting and capillarity Laura Esposito and Alida Bellosi * IRTEC CNR, Research Institute for Ceramics Technology, via Granarolo 64, 48018 Faenza RA, Italy Received 5 February 2001; accepted 12 June 2001 Abstract A bonding technique based on the use of a glass powder interlayer is studied. Examples are presented for the systems formed by ZrO 2 3 mol%Y 2 O 3 ) and the composite 80Al 2 O 3 ±20ZrO 2 wt.%) and a silicate glass as interlayer. The microstructure and mechanical resistance of the joints are also reported. Ó 2001 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc. Keywords: Bonding; Ceramics; Oxides; Glasses; Interfaces Introduction Polycrystalline oxide materials like Al 2 O 3 or ZrO 2 and related composites have been widely investigated in the last decades in terms of microstructure [1±6] and thermo- mechanical properties [7±9]. Most of the characteristics of these oxides are related and governed by the microstructure, i.e. the mean grain size and distribution, the compo- sition and thickness of the intergranular phase, etc. These features play a key role in determining the ®nal properties of the material and depend primarily on the speci®c cations segregation from impurities and/or sintering aids) occurring during sintering and on the consequent interfacial force balance between the grains [10]. The interac- tions occurring at high temperature among the phases that come in contact are fun- damental also to produce adhesion between two dierent materials. The wetting on ¯owing capability of the intergranular phase, is a key factor for example for the pro- duction of bonds through the use of a pressure applied on two ceramic pieces in contact [11±14]. As an alternative to pressure-assisted joining methods, a glass or glass±ceramic in- terlayer placed between two ceramic pieces can be used to promote adhesion [15±17]. Scripta Materialia 45 2001) 759±766 www.elsevier.com/locate/scriptamat * Corresponding author. E-mail address: bellosi@irtec1.irtec.bo.cnr.it A. Bellosi). 1359-6462/01/$ - see front matter Ó 2001 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc. PII:S1359-646201)01092-2