Enhancement of mechanical properties of ceramic membranes and solid electrolytes
AssigneeGas Research Institute
InventorsYousheng Shen, Ashok V. Joshi, Dale M. Taylor, Michael J. Boettcher, Kevin Krist, Anil V. Virkar
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Abstract
Enhancement of mechanical properties of ceramic membranes by introduction of a uniformly distributed high-temperature oxidation-resistant metal phase into the brittle ceramic phase to achieve mechanically strong ceramic/metal composites operable in an oxidation atmosphere and at elevated temperatures.
Claims27
A process for enhancement of mechanical properties of mixed ionic and electronic conducting composite ceramic gas impervious membranes comprising, forming a mixture of about 50 to about 90 volume percent ceramic powder and about 10 to about 50 volume percent metal powder of a high-temperature oxidation resistant metal, each of said powders having average powder sizes of less than about 50 micrometers, forming a green body of said mixture, and sintering said green body in an oxidation atmosphere at a temperature and for a time to obtain a high density of greater than about 95 percent of the theoretical value forming a composite membrane about 1 to about 50 microns thick of said ceramic and metal having a non-homogeneous microstructure of a predominantly ionic conducting continuous phase and a predominantly electronic conducting continuous phase providing ionic conduction across said membrane by pressure differential and exhibiting enhanced mechanical properties compared to said ceramic alone.
A mixed ionic and electronic conducting sintered ceramic/metal composite gas impervious membrane about 1 to about 50 microns thick having a non-homogeneous mixed microstructure comprising about 50 to about 90 volume percent ceramic phase and about 10 to about 50 volume percent high-temperature oxidation resistant metal phase uniformly distributed in said ceramic phase, said membrane having a predominantly ionic conducting continuous ceramic phase and a predominantly electronic conducting metal phase providing ionic conduction across said membrane by pressure differential and exhibiting enhanced mechanical properties, compared to said ceramic alone, of increased fracture strength .sigma..sub.f of at least about 20 percent and increased critical stress intensity factor (mode I) K.sub.Ic of at least about 20 percent.
Dependencies are inferred from the claim text.