Dense sintered product

Patent metadata

Field	Value
Publication number	US-11370710-B2
Application number	US-201815884269-A
Country	US
Kind code	B2
Filing date	Jan 30, 2018
Priority date	Jan 31, 2017
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

Sintered producthaving a chemical analysis such that, in mass percentages:SiO2 content is greater than 0.2% and less than 2%, andCaO content is greater than 0.1% and less than 1.5%, andMgO content is less than 0.3%, andalumina and other elements being the complement at 100%, the content of other elements being less than 1.5%,having a relative density greater than 90%,comprising, for more than 90% of its volume, a stack of ceramic platelets (10) laid flat, all of said platelets having an average thickness less than 3 μm, more than 95% by number of said platelets each containing more than 95% by mass of alumina,having a width (l) greater than 81 mm.

First claim

The invention claimed is:

1. An electronic device housing comprising a product, the product comprising:
Al 2 O 3 ;
greater than 0.75% by mass and less than 2% by mass SiO 2 ;
greater than 0.55% by mass and less than 1.5% by mass CaO;
less than 0.3% by mass MgO;
the Al 2 O 3 , SiO 2 , CaO, and MgO comprising at least 98.5% by mass of the product;
the product having a relative density greater than 90%, and greater than 90% by volume of the product comprising substantially parallel ceramic platelets having an average length greater than 5 μm and a thickness less than 3 μm and ceramic particles having an average length less than 1 μm, the ceramic particles comprising less than 7% by volume of the ceramic platelets and the ceramic particles.

2. The electronic device housing of claim 1 , wherein the product has:
a crack initiation toughness K1c greater than 5.5 MPa·m 1/2 ;
a toughness Kjc greater than 7 MPa·m 1/2 ;
a relative density greater than 95%; and
a width greater than 100 mm.

3. The electronic device housing of claim 1 , wherein the product has:
a crack initiation toughness K1c greater than 6 MPa·m 1/2 ,
a toughness Kjc greater than 8 MPa·m 1/2 ;
a relative density greater than 98%; and
a width greater than 150 mm.

4. The electronic device housing of claim 1 , wherein more than 90% by number of the ceramic platelets have a length of less than 70 μm.

5. The electronic device housing of claim 1 , wherein:
the product comprises less than 1.5% by mass SiO 2 ;
the sum of CaO and MgO comprise greater than 0.1% by mass and less than 0.8% by mass of the product; and
the Al 2 O 3 , SiO 2 , CaO, and MgO comprise at least 99.2% by mass of the product.

6. The electronic device housing of claim 1 , wherein the sintered product has a width, as measured in a direction parallel to a plane of the substantially parallel ceramic platelets, greater than 60 mm.

7. The electronic device housing of claim 6 , wherein the width is greater than 100 mm.

8. The electronic device housing of claim 1 , wherein the sintered product further comprises greater than 1% by mass being in the form of platelets.

9. The electronic device housing of claim 1 , wherein the average length of the ceramic particles is at least 10 times less than the average length of the ceramic platelets.

10. The electronic device housing of claim 1 , wherein the ceramic particles is greater than 2% by volume of the ceramic platelets and ceramic particles.

11. An electronic device housing comprising a sintered product, the sintered product comprising:
Al 2 O 3 ;
greater than 0.2% by mass and less than 2% by mass SiO 2 ;
greater than 0.1% by mass and less than 1.5% by mass CaO;
less than 0.3% by mass MgO;
the Al 2 O 3 , SiO 2 , CaO, and MgO comprising at least 98.5% by mass of the sintered product;
the sintered product having a relative density greater than 90%, and greater than 90% by volume of the sintered product comprising substantially parallel ceramic platelets having an average length greater than 5 μm and a thickness less than 3 μm and ceramic particles having an average length less than 1 μm, the ceramic particles comprising less than 7% by volume of the ceramic platelets and the ceramic particles; and
wherein the sintered product has a width, as measured in a direction parallel to a plane of the substantially parallel ceramic platelets, greater than 60 mm.

Assignees

• Apple Inc

Inventors

• Benameur Nassira
• His Christian
• Leloup Jérôme

Classifications

• C04B35/111 Primary

  Fine ceramics · CPC title

• C04B2235/5292

  Flakes, platelets or plates · CPC title

• C04B2237/30

  Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates · CPC title

• C04B2235/3208

  Calcium oxide or oxide-forming salts thereof, e.g. lime · CPC title

• C04B2235/3418

  Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint · CPC title