Magnetic recording disk and disk drive with improved head-disk interface

• US 5,569,506 A
• Filed: 10/06/1993
• Issued: 10/29/1996
• Est. Priority Date: 10/06/1993
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Mirzamaani, Mohammad T., Wu, Anthony W., Jahnes, Christopher V., Kaufman, James H., Metin, Serhat
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US08/132,543
• Time in Patent Office: 1,119 Days
• Field of Search: 428/695, 428/694 T, 428/694 TP, 428/694 TC, 428/336, 428/408, 428/900, 428/141, 428/65.3, 428/65.4, 428/65.5, 360/133, 360/135, 360/900
• US Class Current: 428/833.2
• CPC Class Codes: C23C 14/165 by cathodic sputtering
• CPC Class Codes: C23C 14/541 Heating or cooling of the substrates
• CPC Class Codes: C23C 16/003 Coating on a liquid substrate
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: G11B 5/7368 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 Class Codes: G11B 5/73913 Composites or coated substrates
• CPC Class Codes: G11B 5/73919 Aluminium or titanium elemental or alloy substrates
• CPC Class Codes: G11B 5/73921 Glass or ceramic substrates
• CPC Class Codes: Y10S 360/90 Disk drive packaging
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A thin film metal alloy magnetic recording disk has an improved protective overcoat that creates a low level of static friction in a contact start/stop disk drive. The disk has an amorphous carbon overcoat containing a transition liquid metal interlayer (TLMI). The carbon overcoat is formed by depositing an initial amorphous carbon layer to a first thickness, then depositing an interlayer material of a low-melting point metal or metal alloy (such as In or In--Nb) while maintaining the temperature of the disk substrate above the melting point of the interlayer material, and then depositing a top additional layer of amorphous carbon. Because the initial carbon layer presents a nonwetting surface, the interlayer material "balls up" on the carbon and forms discontinuous spheres of the interlayer material. The additional top layer of carbon bonds to the initial carbon layer and to the metal or metal alloy spheres. The completed disk protective overcoat presents a continuous but textured surface of amorphous carbon for the head-disk interface in the disk drive.

Claims

1. A thin film magnetic recording disk comprising:

a rigid substrate;

an underlayer formed on the substrate;

a magnetic layer comprising a cobalt-based alloy formed on the underlayer; and

an essentially amorphous carbon overcoat formed on the magnetic layer, the overcoat comprising a first essentially amorphous carbon layer deposited directly on and in contact with the magnetic layer, a plurality of discontinuous generally rounded grains of a metal or metal alloy deposited on the surface of the first carbon layer, the grains being formed of a metal or an alloy of a metal selected from the group consisting of indium (In), gallium (Ga), silver (Ag), tin (Sn), aluminum (Al), gold (Au), bismuth (Bi), lead (Pb), cadmium (Cd), scandium (Sc), and tellurium (Te), and a second essentially amorphous carbon layer formed on the first carbon layer and the metal or metal alloy grains.

2. A thin film disk according to claim 1 wherein the first or second essentially amorphous carbon layer includes an element selected from the group consisting of hydrogen and nitrogen.

3. A thin film disk according to claim 1 wherein the metal alloy forming the grains on the first carbon layer is an alloy formed of metals selected from the group consisting of indium (In), gallium (Ga), silver (Ag), tin (Sn), aluminum (Al), gold (Au), bismuth (Bi), lead (Pb), cadmium (Cd), scandium (Sc), and tellurium (Te).

4. A thin film disk according to claim 1 wherein the metal alloy forming the grains on the first carbon layer is an alloy formed of a metal selected from the group consisting of indium (In), gallium (Ga), silver (Ag), tin (Sn), aluminum (Al), gold (Au), bismuth (Bi), lead (Pb), cadmium (Cd), scandium (Sc), and tellurium (Te), and an element selected from the group consisting of cobalt (Co), niobium (Nb), titanium (Ti), vanadium (V), chromium (Cr), and tungsten (W).

5. A thin film disk according to claim 1 wherein the substrate is either an aluminum alloy disk having a NiP surface coating, or a glass disk.

6. A thin film disk according to claim 4 wherein the metal alloy is In--Cr or In--Nb.

7. A thin film disk according to claim 6 wherein the In--Nb alloy contains Nb in an amount between approximately 30 and 50 atomic percent.

8. An improved contact start/stop (CSS) magnetic recording rigid disk drive wherein the improvement comprises a thin film magnetic recording disk having a protective overcoat of essentially amorphous carbon, the overcoat comprising a first layer of essentially amorphous carbon deposited directly on and in contact with the magnetic layer, a plurality of discontinuous generally rounded metal or metal alloy grains deposited on the surface of the first carbon layer, the grains being formed of a metal or an alloy of a metal selected from the group consisting of indium (In), gallium (Ga), silver (Ag), tin (Sn), aluminum (Al), gold (Au), bismuth (Bi), lead (Pb), cadmium (Cd), scandium (Sc), and tellurium (Te), and a second essentially amorphous carbon layer formed over the first carbon layer and the metal or metal alloy grains, whereby the second carbon layer has a generally textured surface caused by the underlying metal or metal alloy grains.