Zirconia article with high alumina content, process of production and use thereof

Patent metadata

Field	Value
Publication number	US-11180417-B2
Application number	US-201816484858-A
Country	US
Kind code	B2
Filing date	Feb 8, 2018
Priority date	Feb 15, 2017
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

The invention relates to a porous zirconia article in particular for use in the dental or orthodontic field, the porous zirconia article comprising ZrO2: 80 to 87 wt. %, Y2O3: 3 to 5 wt. %, Al2O3: 10 to 14 wt. %, wt. % with respect to the weight of the porous zirconia article, the porous zirconia article being characterized by a BET surface from 15 to 100 m2/g. The invention also relates to a sintered zirconia article in particular for use in the dental or orthodontic field, the sintered zirconia article comprising ZrO2: 80 to 87 wt. %, Y2O3: 3 to 5 wt. %, Al2O3: 10 to 14 wt. %, wt. % with respect to the weight of the porous zirconia article, the sintered zirconia article being characterized by a corundum crystal phase content of 7 to 12 wt. % and a flexural strength of at least 2,000 MPa.

First claim

What is claimed is:

1. A sintered zirconia article comprising:
ZrO 2 : 80 to 87 wt. %,
Y 2 O 3 : 3 to 5 wt. %, and
Al 2 O 3 : 10 to 14 wt. %,
wherein one or more of the zirconia and alumina has a grain size from 200 nm to 300 nm;
the sintered zirconia article being characterized by a corundum crystal phase content of 7 to 12 wt. %, and
the sintered zirconia article having a flexural strength of at least 2,000 MPa according to ISO 6872:2015;
wherein wt. % is with respect to the weight of the sintered zirconia article.

2. The sintered zirconia article of claim 1 , further being characterized by one or more of the following features:
zirconia crystal phase content of tetragonal phase: more than 85 wt. %;
zirconia crystal phase content of cubic phase: less than 2 wt. %; and
zirconia crystal phase content of monoclinic phase: less than 2 wt. %.

3. The sintered zirconia article of claim 1 , further being characterized by one or more of the following features:
fracture toughness: at least 7 MPa*m 0.5 according to ISO 6872:2015;
density: more than 98.5% with respect to theoretical density; and
translucency: less than 20% determined on a polished sample having a thickness of 1 mm.

4. The sintered zirconia article claim 1 , having the shape of a dental article, orthodontic article, or part thereof.

5. A process for producing a sintered zirconia article of claim 1 , the process comprising:
providing a porous zirconia article comprising:
ZrO 2 : 80 to 87 wt. %,
Y 2 O 3 : 3 to 5 wt. %, and
Al 2 O 3 : 10 to 14 wt. %,
wherein wt. % is with respect to the weight of the porous zirconia article;
the porous zirconia article being characterized by one or more of the following parameters:
density: from 40 to 60% of theoretical density,
average connected pore diameter: from 2 to 100 nm,
BET surface: from 11 to 100 m 2 /g, and
Vickers hardness: from 10 to 100 HV1;

providing a porous zirconia article by:
providing a composition comprising:
ZrO 2 in the term of inorganic oxide: 80 to 87 wt. %,
Y 2 O 3 in the term of inorganic oxide: 3 to 5 wt. %, and
Al 2 O 3 in the term of inorganic oxide: 10 to 14 wt. %,
wherein wt. % is with respect to the weight of the composition;

processing the composition by a casting technique or an additive manufacturing technique; and
applying a calcining step; and

applying a sintering step to obtain the sintered zirconia article,
provided the process is free of a hot isostatic pressing step.

6. The sintered zirconia article of claim 1 , further being characterized by one or more of the following features:
fracture toughness: at least 7 MPa*m 0.5 according to ISO 6872:2015;
density: more than 98.5% with respect to theoretical density; and
translucency: less than 20% determined on a polished sample having a thickness of 1 mm.

7. The sintered zirconia article of claim 6 , having the shape of a dental article, orthodontic article, or part thereof.

8. The process of claim 5 , wherein the sintered zirconia article is further characterized by one or more of the following features:
zirconia crystal phase content of tetragonal phase: more than 85 wt. %;
zirconia crystal phase content of cubic phase: less than 2 wt. %; and
zirconia crystal phase content of monoclinic phase: less than 2 wt. %.

9. The process of claim 5 , wherein the sintered zirconia article is further characterized by one or more of the following features:
fracture toughness: at least 7 MPa*m 0.5 according to ISO 6872:2015;
density: more than 98.5% with respect to theoretical density; and
translucency: less than 20% determined on a polished sample having a thickness of 1 mm.

Assignees

• 3M Innovative Properties Co

Inventors

• Theelke Bjorn
• Dittmann Rainer K

Classifications

• A61K6/822

  comprising rare earth metal oxides · CPC title

• C01P2006/12

  Surface area · CPC title

• A61C13/082

  Cosmetic aspects, e.g. inlays; Determination of the colour (A61C19/10 takes precedence) · CPC title

• C01G25/02

  Oxides · CPC title

• C04B35/4885 Primary

  with aluminium oxide · CPC title