# US 5,707,705 A · Titanium or titanium-alloy substrate for magnetic-recording media > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,705 A - Document ID: US5707705A - Status: Granted - Kind: A - Application number: 08/118,147 - Filed: 1993-09-08 - Granted: 1998-01-13 - Earliest claimed: 1993-09-08 - Assignees: Tulip Memory Systems, Inc. - Inventors: Carl W. Nelson; Richard D. Weir; Richard S. Weir - Web page: https://patentgrep.com/patent/US5707705A ## CPC - G11B 5/8404: {manufacturing base layers} - G11B 5/73919: {Aluminium or titanium elemental or alloy substrates} - Y10S 428/90: Magnetic feature - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract An improved magnetic-recording disk and a process for manufacturing magnetic-recording disks are disclosed. Precision cold-rolled titanium or titanium alloy is the substrate for a magnetic-recording disk. The surface of the substrate may be hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding. A hard coating may be applied to the substrate by evaporative reactive ion plating or reactive sputtering of aluminum nitride, silicon nitride, silicon carbide, or nitrides, carbides, or borides of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, or tungsten. ## Claims ### Claim 1 A magnetic-recording disk comprising: a disk-shaped substrate composed of titanium or a titanium alloy, wherein the substrate includes a surface cleaned by sputter etching and then hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding; and a coating of a magnetic-recording material overlying the hardened surface of the substrate. ### Claim 2 (depends on 1) A magnetic-recording disk as recited in claim 1 wherein the coating of magnetic-recording material is applied by sputter deposition. ### Claim 3 (depends on 1) A magnetic-recording disk as recited in claim 1 wherein the substrate is precision blanked from flat precision cold-rolled titanium or a titanium alloy. ### Claim 4 (depends on 1) A magnetic-recording disk as recited in claim 1 wherein the substrate is a titanium alloy comprising Ti, 3% Al, and 2.5% V. ### Claim 5 (depends on 1) A magnetic-recording disk as recited in claim 1 further including a hard material coating on the hardened surface of the substrate, wherein the hard material coating is aluminum nitride, silicon nitride, silicon carbide, or a nitride, carbide, or boride of a metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten, and is applied prior to the application of the magnetic-recording material. ### Claim 6 (depends on 5) A magnetic-recording disk as recited in claim 5 wherein the hard material coating has a thickness of at least 0.5 micrometers. ### Claim 7 (depends on 5) A magnetic-recording disk as recited in claim 5 wherein the hard material coating is applied by evaporative reactive ion plating or reactive sputtering. ### Claim 8 (depends on 1) A magnetic-recording disk as recited in claim 1 wherein said surface hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding has a Vickers harness of at least 1000 kg/mm.sup.2. ### Claim 9 (depends on 1) A magnetic-recording disk as recited in claim 1 wherein said surface is hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding to a depth of at least 15 micrometers. ### Claim 10 A magnetic-recording disk comprising: a disk-shaped substrate composed of titanium or a titanium alloy; a hard material applied coating overlying a surface of the substrate, wherein the hard material coating is aluminum nitride, silicon nitride, silicon carbide, or a nitride, carbide, or boride of a metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten, and is applied prior to the application of the magnetic-recording material, and wherein the hard material coating has a thickness of at least 0.5 micrometers; and a coating of a magnetic-recording material overlying the hard material coating. ### Claim 11 (depends on 10) A magnetic-recording disk as recited in claim 10 wherein the coating of magnetic-recording material is applied by sputter deposition. ### Claim 12 (depends on 10) A magnetic-recording disk as recited in claim 10 wherein the substrate is precision blanked from flat precision cold-rolled titanium or a titanium alloy. ### Claim 13 (depends on 10) A magnetic-recording disk as recited in claim 10 wherein the substrate is a titanium alloy comprising Ti, 3% Al, and 2.5% V. ### Claim 14 (depends on 10) A magnetic-recording disk as recited in claim 10 wherein the surface is cleaned by sputter etching and then hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding. ### Claim 15 (depends on 10) A magnetic-recording disk as recited in claim 10 wherein the hard material coating is applied by evaporative reactive ion plating or reactive sputtering. ### Claim 16 (depends on 14) A magnetic-recording disk as recited in claim 14 wherein said surface hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding has a Vickers harness of at least 1000 kg/mm.sup.2. ### Claim 17 (depends on 14) A magnetic-recording disk as recited in claim 14 wherein said surface is hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding to a depth of at least 15 micrometers.