Dense sintered product

Patent metadata

Field	Value
Publication number	US-11578005-B2
Application number	US-201816481236-A
Country	US
Kind code	B2
Filing date	Jan 30, 2018
Priority date	Jan 31, 2017
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

Sintered product having a relative density of greater than 90%, with, to more than 80% of the volume thereof, a stack of flat ceramic platelets, the assembly of the platelets having a mean thickness of less than 3 μm, having a width of greater than 50 mm, and including more than 20% of alumina, as a percentage on the basis of the weight of the product. The width of the product is the largest dimension measured in the plane in which the length of the product is measured, along a direction perpendicular to the direction of the length. The length of the product is the largest dimension thereof in a plane parallel to the general plane in which the platelets extend.

First claim

The invention claimed is:

1. A sintered product
having a relative density of greater than 90%,
comprising, to more than 80% of the volume thereof, a stack of ceramic platelets ( 10 ), each platelet having major faces that are substantially flat and parallel to one another, the ceramic platelets being stacked flat, so that said major faces of said platelets extend parallelly to a general plane, the set of said platelets having a mean thickness of less than 3 μm,
having a width (l) of greater than 50 mm, and
comprising more than 20% of alumina, as a percentage on the basis of the weight of the product,
the width (l) of the product being the largest dimension measured in the plane (C) in which the length of the product is measured, along a direction perpendicular to the direction of said length,
the length (L) of said product being the largest dimension thereof in a plane (C) parallel to said general plane.

2. The product as claimed in claim 1 , having
a crack initiation toughness K 1c of greater than 3.5 MPa·m 1/2 and/or
a toughness K jc of greater than 6 MPa·m 1/2 , and/or
a relative density of greater than 95%, and/or
a mean platelet thickness of less than 2.0 μm, and/or
a width of greater than 60 mm, and/or wherein
more than 70% by number of the platelets comprise more than 70% by weight of alumina.

3. The product as claimed in claim 2 , having
a crack initiation toughness K 1c of greater than 5 MPa·m 1/2 , and/or
a toughness K jc of greater than 8 MPa·m 1/2 , and/or
a relative density of greater than 98%, and/or
a mean platelet thickness of less than 1.5 μm, and/or
a width of greater than 85 mm, and/or wherein
more than 95% by number of the platelets comprise more than 95% by weight of alumina.

4. The product as claimed in claim 1 , containing more than 1% and less than 20% of boron nitride, by weight on the basis of the weight of said product, the boron nitride being present in the form of platelets.

5. The product as claimed in claim 1 , wherein more than 90% by number of the platelets have a length of less than 70 μm and greater than 2 μm.

6. The product as claimed in claim 1 , having a chemical analysis such that, as percentages by weight:
the content of SiO 2 is greater than 0.2% and less than 13.5%, and
the content of CaO+MgO is greater than 0.1% and less than 4.5%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 2%,
or such that
the content of SiO 2 is greater than 0.2% and less than 13.5%, and
the content of CaO is greater than 0.1% and less than 4.5%, and
the content of MgO is less than 0.3%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 2%,
or such that
the content of SiO 2 is greater than 0.2%, and less than 13.5%, and
the content of MgO is greater than 0.1% and less than 4.5%, and
the content of CaO is less than 0.3%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 2%,
or such that
the content of optionally stabilized ZrO 2 is greater than 1%and less than 15%, and
the content of SiO 2 is greater than 0.2% and less than 13.5%, and
the content of CaO+MgO is greater than 0.1% and less than 4.5%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 10%,
or such that
the content of SiO 2 is greater than 0.2% and less than 13.5%, and
the content of CaO+MgO is greater than 0.1% and less than 4.5%, and
the content of boron nitride is greater than 1% and less than 20%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 10%,
or such that
the content of optionally stabilized ZrO 2 is greater than 1% and less than 15%, and
the content of SiO 2 is greater than 0.2% and less than 13.5%, and
the content of CaO+MgO is greater than 0.1% and less than 4.5%, and
the content of boron nitride is greater than 1% and less than 20%, and
the total content of Al 2 O 3 and of “other elements” constituting the balance to 100%, the content of other elements being less than 10%.

7. The product as claimed in claim 6 , having a chemical analysis such that, as percentages by weight:
the content of Al 2 O 3 is greater than 95% and less than 99.7%, and
the content of SiO 2 is greater than 0.2% and less than 2%, and
the content of CaO+MgO is greater than 0.1% and less than 1.5%, and
the content of other elements is less than 1.5%,
or such that
the content of Al 2 O 3 is greater than 95% and less than 99.7%, and
the content of SiO 2 is greater than 0.2% and less than 2%, and
the content of CaO is greater than 0.1% and less than 1.5%, and
the content of MgO is less than 0.3%, and
the content of other elements is less than 1.5%,
or such that
the content of Al 2 O 3 is greater than 95% and less than 99.7%, and
the content of SiO 2 is greater than 0.2%, and less than 2%, and
the content of MgO is greater than 0.1% and less than 1.5%, and
the content of CaO is less than 0.3%, and
the content of other elements is less than 1.5%,
or such that
the content of optionally stabilized ZrO 2 is greater han 1% and less than 15%, and
the content of SiO 2 is greater than 0.2% and less than 2%, and
the content of CaO+MgO is greater than 0.1% and less than 1.5%, and
the content of other elements is less than 1.5%, and
the balance to 100% is alumina,
or such that
the content of SiO 2 is greater than 0.2% and less than 2%, and
the content of CaO+MgO is greater than 0.1% and less than 1.5%, and
the content of boron nitride is greater than 1% and less than 20%, and
the content of other elements is less than 1.5%, and
the balance is alumina,
or such that
the content of optionally stabilized ZrO 2 is greater than 1%and less than 15%, and
the content of SiO 2 is greater than 0.2% and less than 2%, and
the content of CaO+MgO is greater than 0.1% and less than 1.5%, and
the content of boron nitride is greater than 1% and less than 20%, and
the content of other elements is less than 1.5%, and
the balance is alumina.

8. The product as claimed in claim 7 , having a chemical analysis such that, as percentages by weight:
the content of Al 2 O 3 is greater than 96.9% and less than 99.5%, and
the content of SiO 2 is greater than 0.2% and less than 1.5%, and
the content of CaO+MgO is greater than 0.1% and less than 0.8%, and
the content of other elements is less than 0.8%
or such that
the content of Al 2 O 3 is greater than 96.8% and less than 99.5%, and
the content of SiO 2 is greater than 0.2% and less than 1.5%, and
the content of CaO is greater than 0.1% and less than 0.8%, and
the content of MgO is less than 0.1%, and
the content of other elements is less than 0.8%,
or such that
the content of Al 2 O 3 is greater than 96.8% and less than 99.5%, and
the content of SiO 2 is greater than 0.2%, and less than 1.5%, and
the content of MgO is greater than 0.1% and less than 0.8%, and
the content of CaO is less than 0.1%, and
the content of other elements is less than 0.8%,
or such that
the content of optionally stabilized ZrO 2 is greater than 1% and less than 15%, and
the content of SiO 2 is greater than 0.2% and less than 1.5%, and
the content of CaO+MgO is greater than 0.1% and less than 0.8%, and
the content of other elements is less than 0.8%, and
the balance to 100% is alumina,
or such that
the content of SiO 2 is greater than 0.2% and less than 1.5%, and
t

Assignees

• Saint Gobain Ct Recherches

Inventors

• Benameur Nassira
• His Christian
• Leloup Jérôme

Classifications

• C04B35/638

  Removal thereof · CPC title

• C04B2235/3206

  Magnesium oxides or oxide-forming salts thereof · CPC title

• C04B2235/5296

  with a defined aspect ratio, e.g. indicating sphericity · CPC title

• C04B2235/6022

  Injection moulding · CPC title

• C04B2235/5463

  Particle size distributions · CPC title