The effects of microstructure on failure initiation of sodiumbeta" alumina solid electrolytes has been investigated by acoustic emission detection. Mode I failure initiation follows Weibull statistics with a modulus of about 2.5. The average critical current densities were 145 rnA cm-2 and 640 rnA cm-2 for large and for small grained electrolytes, respectively. Considerations of failure statistics indicate conditions where proof testing may be necessary to achieve sufficient reliability. These considerations assume complete equivalence between mechanical and electrolytic failure; the indication are, however, that such equivalence is not valid.
The fracture toughness anisotropy was determined for sodium p‐alumina single crystals, using a hardness indent method. For cracks with a habit plane normal to the 00.1 planes, the fracture toughness is ∼2 MPa.m112, whereas for cracks running parallel to the 00.1 planes, it is ∼0.16 MPa.m112. This extreme anisotropy may partly explain the difference between calculated and observed critical current densities jor mode I failure initiation of poly crystalline solid electrolytes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.