Phase Equilibria Diagrams (American Ceramic Society) database is now available for searching.
http://resolver.library.cornell.edu/misc/7086184
provide 23,400 phase diagrams for oxides, non-oxides, salts, carbides, nitrides, borides, compound semiconductors, pnictides and chalcogenides.
Example – search CeO2-ThO2-ZrO2 (includes hyphens and caps)

This is a separate database from the American Metals Society. That is called ASM Alloy Phase Diagrams, http://resolver.library.cornell.edu/misc/7055187

See the Engineering Library website’s database by discipline page for the latest list of available databases,
http://engineering.library.cornell.edu