Protective layer for mitigating protruding defects in magnetic tape recording media

Patent metadata

Field	Value
Publication number	US-11322175-B2
Application number	US-201916447746-A
Country	US
Kind code	B2
Filing date	Jun 20, 2019
Priority date	May 18, 2016
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A magnetic recording medium according to one embodiment includes an underlayer and a magnetic layer above the underlayer. The magnetic layer includes a first magnetic material and particulates. A solid protective layer is positioned above the magnetic layer, the protective layer including a second material. At least some of the particulates of the magnetic layer protrude completely through the protective layer. A method for forming a magnetic recording medium according to one embodiment includes forming a magnetic layer above a substrate, the magnetic layer including a first magnetic material and particulates, and forming a solid protective layer above the magnetic layer to a thickness whereby some of the particulates protrude through the protective layer and are exposed along an upper surface of the protective layer.

First claim

What is claimed is:

1. A magnetic recording medium, comprising:
an underlayer;
a magnetic layer above the underlayer, the magnetic layer including a first magnetic material and particulates, wherein the first magnetic material has a different composition than the particulates; and
a solid protective layer above the magnetic layer, the protective layer including a second material, wherein a composition of the protective layer is different than a composition of the magnetic layer, wherein the protective layer is a cured layer,
wherein at least some of the particulates of the magnetic layer protrude completely through the protective layer.

2. A magnetic recording medium, comprising:
an underlayer;
a magnetic layer above the underlayer, the magnetic layer including a first magnetic material and particulates, wherein the first magnetic material has a different composition than the particulates; and
a protective layer above the magnetic layer, the protective layer including a second material,
wherein at least some of the particulates of the magnetic layer protrude completely through the protective layer,
wherein the second material is magnetic, wherein a composition of the protective layer is different than a composition of the magnetic layer.

3. The magnetic recording medium as recited in claim 2 , wherein a total thickness of the magnetic and protective layers is a design magnetic thickness of the magnetic recording medium.

4. The magnetic recording medium as recited in claim 1 , wherein the second material is nonmagnetic.

5. The magnetic recording medium as recited in claim 1 , wherein the protective layer is constructed of a material that does not contain the particulates.

6. The magnetic recording medium as recited in claim 1 , wherein a thickness of the protective layer is at least 10% of a total thickness of the magnetic recording medium.

7. The magnetic recording medium as recited in claim 1 , wherein the first magnetic material in the magnetic layer includes barium ferrite.

8. The magnetic recording medium as recited in claim 1 , wherein the second material in the protective layer includes barium ferrite.

9. The magnetic recording medium as recited in claim 1 , wherein the particulates include aluminum oxide.

10. The magnetic recording medium as recited in claim 1 , wherein some of the particulates protrude beyond and are thereby exposed along an upper surface of the protective layer.

11. The magnetic recording medium as recited in claim 1 , comprising a lubricating material embedded in the protective layer.

12. The magnetic recording medium as recited in claim 11 , wherein the lubricating material is configured to migrate through the protective layer.

13. The magnetic recording medium as recited in claim 1 , comprising a lubricant on an outer surface of the protective layer, the lubricant having a different composition than the protective layer.

14. A method for forming a magnetic recording medium, the method comprising:
forming a magnetic layer above a substrate, the magnetic layer including a first magnetic material and particulates, wherein the first magnetic material has a different composition than the particulates;
forming a protective layer above the magnetic layer to a thickness whereby some of the particulates protrude through the protective layer and are exposed along an upper surface of the protective layer; and
curing the protective layer,
wherein a composition of the protective layer is different than a composition of the magnetic layer.

15. The method as recited in claim 14 , comprising adding a lubricant on an outer surface of the protective layer.

16. The method as recited in claim 14 , wherein the protective layer is viscous when formed.

17. The method as recited in claim 15 , wherein the lubricant is added on the outer surface of the protective layer after formation of the protective layer.

18. The method as recited in claim 14 , wherein at least one of the layers of the magnetic recording medium is formed using extrusion.

19. The method as recited in claim 14 , wherein at least two layers of the magnetic recording medium are co-extruded, and are cured together.

Assignees

• IBM

Inventors

• Biskeborn Robert G
• Lo Calvin S

Classifications

• G11B5/737

  Physical structure of underlayer, e.g. texture · CPC title

• G11B5/728

  containing a bonding agent in the protective coating · CPC title

• G11B5/726

  Two or more protective coatings (inorganic carbon protective coating G11B5/727) · CPC title

• G11B5/708 Primary

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

• G11B5/72

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