EP0098343A2 - Recuit par laser de substrats métalliques - Google Patents

Recuit par laser de substrats métalliques Download PDF

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Publication number
EP0098343A2
EP0098343A2 EP83101764A EP83101764A EP0098343A2 EP 0098343 A2 EP0098343 A2 EP 0098343A2 EP 83101764 A EP83101764 A EP 83101764A EP 83101764 A EP83101764 A EP 83101764A EP 0098343 A2 EP0098343 A2 EP 0098343A2
Authority
EP
European Patent Office
Prior art keywords
substrate
inches
disk substrate
cms
melting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83101764A
Other languages
German (de)
English (en)
Other versions
EP0098343A3 (fr
Inventor
Flossie Li-Sheng Lin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Publication of EP0098343A2 publication Critical patent/EP0098343A2/fr
Publication of EP0098343A3 publication Critical patent/EP0098343A3/fr
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F3/00—Changing the physical structure of non-ferrous metals or alloys by special physical methods, e.g. treatment with neutrons

Definitions

  • This invention relates to a method of improving the microstructure homogeneity of a metallic alloy disk substrate having second phase defects on the surface thereof.
  • shock hardening uses extremely high power densities and short interaction times to produce a metal vapour cloud which leaves the metal surface with a high enough velocity to create a shock wave at the metal surface.
  • Hole drilling uses a laser to produce holes in materials by vapourization of the substrate by the laser beam.
  • Deep penetration welding uses a moderate power density and a moderate interaction time to produce deep melting in metal articles to be joined. The melting is usually accompanied by the formation of a hollow cavity which is filled with plasma and metal vapour.
  • transformation hardening is performed at low power densities and long interaction times.
  • Shock hardening and hole drilling are usually performed using pulsed lasers since pulsed lasers are the most reasonable way to achieve the desired combination of power density and interaction time.
  • Deep penetration welding and transformation hardening are usually performed using a continuous laser and the interaction time is controlled by sweeping the laser beam over the area to be welded or hardened.
  • the region of the present invention is shown as "skin melting". This region is bounded on one side by conditions where surface vapourization will occur and on the other side by conditions where surface melting will occur. Transformation hardening is performed at conditions where surface melting will not occur while shock hardening, hole drilling and deep penetration welding all involve a significant amount of surface vapourization.
  • U.S. 4,122,240 discloses the melting of a metal surface layer by a high energy source such as a laser to produce metallurgical changes in the surface. This patent does not teach any subsequent polishing of a surface made more homogeneous by melting.
  • a method of improving the microstructure homogeneity of a metallic alloy disk substrate having second phase defects on the surface thereof characterised in that the method comprises the steps of rotating said disk substrate at a predetermined velocity, heating said rotating substrate with a laser beam to melt said substrate surface including said second phase defects, whereby said melted second phase defects are diffused into said melted surface to produce a single phase layer on said substrate surface, and polishing said single phase surface to produce an essentially defect-free surface.
  • the present invention is applicable for use with aluminium alloy disk substrates which contain second phase defects therein.
  • An example is an aluminium-magnesium alloy containing second phase defects of other material.
  • the present invention employs a high energy source to first melt the surface layer of an aluminium substrate including melting the second phase defects thereon. The melted second phase defects diffuse into the surrounding melted material and the cooling is such that the second phase defect material can not reform the substrate surface. This produces a single phase layer which makes the substrate surface more homogeneous. This is followed by a polishing process of the cooled surface to produce a highly polished, essentially defect-free surface without changing the bulk properties of the substrate.
  • the present invention is particularly adapted for use in the fabrication of metallic substrates which are to be used as substrates for magnetic recording disks.
  • Such substrates especially those intended for use with thin film magnetic recording layers thereon produced by some type of evaporative technique, require a very smooth surface.
  • the nature of the aluminium alloys used for these substrates is such that they usually contain second phase defects which render their topography inhomogeneous. Such inhomogeneities remain in the surface of present substrates, even after efforts to remove them, such as by machining, polishing, grinding, etc.
  • such substrates are first subjected to annealing by a high energy source such as a laser to melt the outer layer of the substrate surface.
  • a high energy source such as a laser to melt the outer layer of the substrate surface.
  • This melting melts both the regular aluminium alloy on the surface as well as any second phase defects present thereon.
  • the second phase defects diffuse into the surrounding melted.aluminium alloy, and because of the rapid cooling after melting, these second phase defects do not reform on the substrate surface.
  • the surface layer is a single phase layer.
  • the circular substrate is rotated while the laser scans the rotating disk to produce the desired heating.
  • the heating is carried out in the presence of an inert gas, primarily to prevent plasma formation, which tends to reflect incident energy from the surface to be heated and to defocus the laser beam.
  • a coupon of an aluminium magnesium alloy having a thickness of 0.381 cms (0.150 inches) and identified as 5086 Al-Mg was moved at a linear velocity of 2.54 cms (1 inch)/second while a 500 watt pulsed Co 2 layer scanned the coupon surface. After treating the entire coupon surface, the annealed surface was polished to remove about .0025 cms (.001 inch) of the melted/solidified layer.
  • Comparison of microphotographs of the coupon surface before and after the annealing and polishing treatment of this invention showed a significant improvement in the quality of surface finish.
  • the resulting surface was essentially defect-free and showed a smooth single phase layer extending some distance into the coupon.
  • Cross-sectional microphotographs showed a melting of approximately the upper 0.005 inches of the substrate material.
  • a disk 35.56 cms (14 inches) in diameter with a thickness of 0.381 cms (0.150 inch) and composed of the 5086 aluminium alloy was rotated at a maximum velocity of 25.4 cms (10 inches)/second while being scanned radially by a continuous wave Co 2 laser having a maximum output of 4.4 kw. Following this, the annealed layer was polished. Again, microphotographs of the surface before and after treatment in accordance with the present invention showed a major improvement in the homogeneity of the surface.
  • the figure is a graph illustrating the surface melt depth as a function of the linear velocity of rotation of the disk substrate for different levels of applied laser power.
  • the shaded area from a linear velocity of 25.4 cms (10 inches)/second and lower represents the operating area for carrying out the present invention, since as indicated above, higher velocities than 25.4 cms (10 inches)/second can result in undesirable micro-voids and micro-cracks in the treated layer. As would be expected, higher levels of laser power result in greater melt depth for a given linear velocity.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
  • Heat Treatment Of Nonferrous Metals Or Alloys (AREA)
  • Laser Beam Processing (AREA)
EP83101764A 1982-06-29 1983-02-23 Recuit par laser de substrats métalliques Withdrawn EP0098343A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US39325582A 1982-06-29 1982-06-29
US393255 1982-06-29

Publications (2)

Publication Number Publication Date
EP0098343A2 true EP0098343A2 (fr) 1984-01-18
EP0098343A3 EP0098343A3 (fr) 1985-01-23

Family

ID=23553947

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83101764A Withdrawn EP0098343A3 (fr) 1982-06-29 1983-02-23 Recuit par laser de substrats métalliques

Country Status (2)

Country Link
EP (1) EP0098343A3 (fr)
JP (1) JPS599158A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0942075A1 (fr) * 1998-03-09 1999-09-15 Hans u. Ottmar Binder GbR Procédé de traitement de surface d' aluminium, des alliages d' aluminium, de magnesium ou des alliages de magnesium
US7622374B2 (en) 2005-12-29 2009-11-24 Infineon Technologies Ag Method of fabricating an integrated circuit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2341665A1 (fr) * 1976-02-17 1977-09-16 United Technologies Corp Articles metalliques a microstructure composite
FR2341655A1 (fr) * 1976-02-17 1977-09-16 United Technologies Corp Procede de fusion superficielle
FR2393075A1 (fr) * 1977-05-31 1978-12-29 Western Electric Co Procede pour le traitement thermique d'une piece a travailler en metal non ferreux

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5451919A (en) * 1977-10-03 1979-04-24 Toshiba Corp Method of hardening surface of metallic body with high melting point

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2341665A1 (fr) * 1976-02-17 1977-09-16 United Technologies Corp Articles metalliques a microstructure composite
FR2341655A1 (fr) * 1976-02-17 1977-09-16 United Technologies Corp Procede de fusion superficielle
FR2393075A1 (fr) * 1977-05-31 1978-12-29 Western Electric Co Procede pour le traitement thermique d'une piece a travailler en metal non ferreux

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0942075A1 (fr) * 1998-03-09 1999-09-15 Hans u. Ottmar Binder GbR Procédé de traitement de surface d' aluminium, des alliages d' aluminium, de magnesium ou des alliages de magnesium
US7622374B2 (en) 2005-12-29 2009-11-24 Infineon Technologies Ag Method of fabricating an integrated circuit

Also Published As

Publication number Publication date
JPS599158A (ja) 1984-01-18
EP0098343A3 (fr) 1985-01-23

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19840426

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Effective date: 19850724

RIN1 Information on inventor provided before grant (corrected)

Inventor name: LIN, FLOSSIE LI-SHENG