Joining oxide ceramic matrix composites by ionotropic gelation

Abstract

The production of complex‐shaped all‐oxide ceramic matrix composites (Ox‐CMC) is somewhat restricted by their current processing methods, as well as by the lack of applicable joining techniques. Thus, we present a new method for joining Ox‐CMCs based on the gelation of slurries with the polysaccharide polymer alginate. For this investigation, Nextel 610/alumina‐zirconia composites were produced using alginate as binder and aluminum acetate as gelling agent. The joining capabilities of this technique were investigated with microstructural analyses and single‐lap compression shear tests. For that, a slurry‐containing alginate was used to join two composite plates at different stages of the processing: gel state, dried green body and after sintering. Joining composites plates in their gel or green state was successful as the joints showed shear strength values similar to the interlaminar shear strength of the composites plates. The quality of the joints was attributed to the interactions between the alginate chains of the composite plates and the joint. We also show that even the joining of already sintered Ox‐CMCs is feasible. However, densification cracks and lower shear strength are observed for such cases.

Mechanical properties of large-sized thin architectural ceramic plate enhanced by alumina fibres and in situ mullite whiskers

“…As a family of architectural ceramic products, traditional large-sized ceramic plates with dimensions of more than 800 × 800 mm are attractive and convenient for decoration and they have attracted research interest recently. However, the raw materials for traditional ceramic plates are mineral resources, which are limited and overexploited [1,2]. Thus, there is a significant tendency for ceramic plates to decrease the thickness to reduce energy consumption and improve the utilization rate of mineral raw materials [3,4].…”