Method to fabricate multiphase zirconia material to achieve high fracture toughness
AssigneeJames R. Glidewell Dental Ceramics, Inc.
InventorsDimple Pradhan, Yan Yang, Sreeram Balasubramanian
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Abstract
Yttria-stabilized zirconia ceramic bodies with a composite system comprising two or more phases. The sintered yttria-stabilized zirconia ceramic bodies have localized regions with different yttria concentrations within the composite system. These microregions containing varying yttria concentrations result in a non-uniform distribution of yttria ranges which individually contribute to localized characteristics that synergistically provide improved fracture toughness and machinability.
Claims20
A sintered yttria-stabilized zirconia ceramic body comprising a composite system with different localized yttria concentrations within the composite system, wherein more than 50% of the localized yttria concentrations have a yttria concentration of less than 2.5 mol %, more than 55% of the localized yttria concentrations have a yttria concentration of less than 2.8 mol %, less than 40% of the localized yttria concentrations have a yttria concentration greater than 5.8 mol %, less than 30% of the localized yttria concentrations have a yttria concentration greater than 6.5 mol %, and at least 30% of the localized yttria concentrations have a yttria concentration of between 6 and 7.5 mol %, wherein the sintered yttria-stabilized zirconia ceramic body has a fracture toughness of greater than 5, and the wt % is based on the total weight of the yttria-stabilized zirconia at the respective location.
A sintered yttria-stabilized zirconia ceramic body comprising a composite system with different localized yttria concentrations within the composite system, wherein more than 30% of the localized yttria concentrations have a yttria concentration of less than 2.5 mol %, less than 50% of the localized yttria concentrations have a yttria concentration greater than 5.8 mol %, less than 50% of the localized yttria concentrations have a yttria concentration greater than 6.5 mol %, and at least 35% of the localized yttria concentrations have a yttria concentration of between 6 and 7.5 mol % wherein the sintered yttria-stabilized zirconia body has a fracture toughness of greater than 4, and the mol % is based on the total moles of the yttria-stabilized zirconia at the respective location.
A method comprising:
- mixing a first yttria-stabilized zirconia powder having a yttria concentration of 4 to 8 mol % yttria, based on the total weight of the first powder, with a second yttria-stabilized zirconia powder having a yttria concentration of 2 to 2.6 mol % yttria, based on the total weight of the second powder;
- forming the resulting mixture into a desired shape, and
- sintering the shaped mixture resulting in a yttria-stabilized zirconia ceramic body.
Dependencies are inferred from the claim text.