Protective layer for mitigating protruding defects in magnetic tape recording media

Patent metadata

Field	Value
Publication number	US-11393501-B2
Application number	US-201916447750-A
Country	US
Kind code	B2
Filing date	Jun 20, 2019
Priority date	May 18, 2016
Publication date	Jul 19, 2022
Grant date	Jul 19, 2022

Abstract

A magnetic recording medium according to one embodiment includes a base film and a first nonmagnetic layer above the base film. The first nonmagnetic layer has first nonmagnetic particles. A second nonmagnetic layer is positioned above the first nonmagnetic layer, the second nonmagnetic layer having second nonmagnetic particles. A magnetic layer is positioned above the second nonmagnetic layer, the magnetic layer including a magnetic material.

First claim

What is claimed is:

1. A magnetic recording medium, comprising:
a base film;
a first nonmagnetic layer above the base film, the first nonmagnetic layer having first nonmagnetic particles of a first nonmagnetic material;
a second nonmagnetic layer formed above an upper surface of the first nonmagnetic layer, the second nonmagnetic layer having second nonmagnetic particles; and
a magnetic layer above the second nonmagnetic layer, the magnetic layer including a magnetic material,
wherein the first nonmagnetic layer includes at least one larger particle of the first nonmagnetic material having a dimension that is at least 50% larger than an average diameter of the first nonmagnetic particles in the first nonmagnetic layer,
wherein the at least one larger particle protrudes out of the first nonmagnetic layer and into the second nonmagnetic layer.

2. The magnetic recording medium as recited in claim 1 , wherein the first nonmagnetic particles include α-hematite.

3. The magnetic recording medium as recited in claim 1 , wherein the first nonmagnetic layer further includes particulates.

4. The magnetic recording medium as recited in claim 3 , wherein the second nonmagnetic layer does not contain particulates.

5. The magnetic recording medium as recited in claim 1 , wherein the second nonmagnetic particles include α-hematite.

6. The magnetic recording medium as recited in claim 1 , wherein the second nonmagnetic particles are of a different material than the first nonmagnetic particles.

7. The magnetic recording medium as recited in claim 1 , wherein the first nonmagnetic layer includes at least one particle of the first nonmagnetic material having a dimension that is at least twice as great as an average diameter of the first nonmagnetic particles therein.

8. A magnetic recording medium, comprising:
a base film;
a first nonmagnetic layer above the base film, the first nonmagnetic layer having first nonmagnetic particles;
a second nonmagnetic layer above the first nonmagnetic layer, the second nonmagnetic layer having second nonmagnetic particles; and
a magnetic layer above the second nonmagnetic layer, the magnetic layer including a magnetic material,
wherein the first nonmagnetic layer includes at least one larger particle having a dimension that is greater than a thickness of the first nonmagnetic layer,
wherein the at least one larger particle protrudes out of the first nonmagnetic layer and into the second nonmagnetic layer.

9. The magnetic recording medium as recited in claim 1 , comprising a protective layer above the magnetic layer, the protective layer including a second material.

10. The magnetic recording medium as recited in claim 9 , wherein the second material is magnetic, wherein a composition of the protective layer is different than a composition of the magnetic layer.

11. The magnetic recording medium as recited in claim 10 , wherein a total thickness of the magnetic and protective layers is a design magnetic thickness of the magnetic recording medium.

12. The magnetic recording medium as recited in claim 9 , wherein the second material is nonmagnetic.

13. The magnetic recording medium as recited in claim 9 , wherein the magnetic layer includes a first magnetic material and nonmagnetic particulates.

14. The magnetic recording medium as recited in claim 13 , wherein the protective layer is constructed of a material that does not contain the particulates.

15. The magnetic recording medium as recited in claim 13 , wherein at least some of the particulates of the magnetic layer protrude through the protective layer.

16. The magnetic recording medium as recited in claim 9 , wherein the protective layer is an outermost layer of the magnetic recording medium.

17. The magnetic recording medium as recited in claim 9 , wherein the protective layer includes a lubricating material.

18. The magnetic recording medium as recited in claim 9 , wherein a thickness of the protective layer is at least 10% of a total thickness of the magnetic recording medium.

Assignees

• IBM

Inventors

• Biskeborn Robert G
• Lo Calvin S

Classifications

• G11B5/708 Primary

  characterised by addition of non-magnetic particles to the layer · CPC title

• G11B5/7368

  Non-polymeric layer under the lowermost magnetic recording layer (base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739) · CPC title

• G11B5/716

  characterised by two or more magnetic layers · CPC title

• G11B5/728

  containing a bonding agent in the protective coating · CPC title

• G11B5/72

  Protective coatings, e.g. anti-static {or antifriction} · CPC title