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AssigneeCommonwealth Scientific and Industrial Research Organization
InventorsRonald Charles Garvie, Richard Henri Jan Hannink, Richard Terry Pascoe
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Calcia-partially-stabilized zirconia ceramic materials which contain between 3.3 and 4.7 percent of calcia by weight. Such materials have a fine-scale two-phase microstructure substantially consisting of metastable, tetragonal domains of a critical size within cubic matrix grains, which domains, in regions of high stress, irreversibly transform to normal monoclinic form upon stressing of the body. The materials are produced by firing a zirconia body containing between 3.3 and 4.7 percent by weight of calcia at a temperature between 1700.degree. C and 1950.degree. C and allowing the body to cool at an average rate of at least 175.degree. C per hour to a temperature within the range 1200.degree. to 1450.degree. C; followed by ageing with said temperature range for a time such that peak strength is obtained.
A refractory ceramic consisting essentially of a calcia-partially-stabilised zirconia body, and characterised in that the calcia concentration lies in the range 3.3-4.7 percent by weight of the ceramic body, and in that said body has a fine-scale two-phase microstructure substantially consisting of metastable, tetragonal domains of a critical size within cubic matrix grains, which domains, in regions of high stress, irreversibly transform to normal monoclinic form upon stressing of the body.
A process for forming a partially stabilized zirconia ceramic which consists of firing a zirconia body containing between 3.3 and 4.7 percent by weight of calcia at a temperature between 1700.degree. C and 1950.degree. C and allowing the body to cool at an average rate of at least 175.degree. C per hour until the temperature is within the range 1200.degree. to 1450.degree. C;
A process for fabricating a partially stabilized zirconia ceramic which comprises the steps of:
A process for fabricating a partially stabilized zirconia ceramic which comprises the steps of:
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