Metal oxide ceramic nanomaterials and methods of making and using same
Provided are metal oxide ceramic materials and intermediate materials thereof (e.g., nanozirconia gels, nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles). The nanozirconia gels are formable gels. Also provided are methods of making and using the metal oxide materials and intermediate materials. The nanozirconia gels can be made using, for example, osmotic processing. The nanozirconia gels can be used to make nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental article. The nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles have desirable properties (e.g., optical properties and mechanical properties).
1. A gel comprising a plurality of zirconia nanoparticles and water, wherein the zirconia nanoparticles have an average size of 10 to 30 nm, 95% or more of the zirconia nanoparticles by volume have a size of 45 nm or less, the zirconia nanoparticles are present at 70 to 85% by weight based on the total weight of the gel, and wherein the gel further comprises a processing agent and the processing agent is 2% by weight 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (TODA) and/or electrostatic colloid stabilizer (ESD) and 0.1% by weight polyethylene glycol having a molecular weight of 35,000 g/mol (PEG35K) and 0.05% by weight polyvinylalcohol (PVA) or 0.5% percent by weight PEG35k and 0.05% by weight PVA, wherein the percent by weight values are based on the total weight of the nanoparticles in the gel.
2. The gel of claim 1 , wherein:
i) 99% of nanoparticles by volume have a size less than 60 nm±10 nm;
ii) 95% of nanoparticles by volume have a size less than 40 nm±5 nm;
iii) 50% of nanoparticles by volume have a size less than 20 nm±5 nm; and
iv.) 5% of nanoparticles by volume have a size less than 12 nm±3 nm.
3. The gel of claim 1 , wherein 95% or greater by volume of the zirconia nanoparticles comprise 1 to 5 crystallites.
4. The gel of claim 1 , wherein the amount of the processing agent is 1.5 to 3.3% by weight based on the total weight of the nanoparticles in the gel.
5. The gel of claim 1 , wherein the gel is translucent and has a transmittance at 560 nm wavelength of 60 to 80% for a 1 to 2 mm thick sample of the gel.
6. The gel of claim 1 , wherein the gel has an opalescence of 20 to 30 for a 1 to 2 mm thick sample of the gel.
7. The gel of claim 1 , wherein the gel is redispersible in an aqueous medium.
8. The gel of claim 1 , wherein the zirconia nanoparticles are in a tetragonal phase.
9. The gel of claim 1 , wherein 10% or less of the zirconia nanoparticles are in a cubic and/or a monoclinic phase.
10. The gel of claim 1 , wherein the gel exhibits a viscosity at yield point of 1×10 9 to 12×10 9 mPa·s.
11. The gel of claim 1 , wherein the gel exhibits a yield stress of 1×10 3 to 9×10 3 Pa.
12. The gel of claim 1 , wherein the gel is formable into a free-standing three-dimensional shape.