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Composite Magnetic Disk Substrate

IP.com Disclosure Number: IPCOM000048623D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Hinkel, H: AUTHOR [+4]

Abstract

In a composite laminate structure with an epoxy core 1 reinforced by fibers 2 and metal foils 3, 4, a relatively soft, plastically deformable layer 5, 6, 7 is provided for reducing local stresses at the fiber/metal foil interface, thus ensuring a smooth composite surface.

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Composite Magnetic Disk Substrate

In a composite laminate structure with an epoxy core 1 reinforced by fibers 2 and metal foils 3, 4, a relatively soft, plastically deformable layer 5, 6, 7 is provided for reducing local stresses at the fiber/metal foil interface, thus ensuring a smooth composite surface.

Fig. 1 shows a laminate epoxy core 1 consisting of several layers reinforced by fibers 2. When the different laminates are pressed together under the application of heat, fibers 2 may deform the hard metal foils 3, 4 which are preferably made of steel. To avoid such deformation, soft, plastically deformable copper layers 5. 6 are provided between core 1 and metal foils 3, 4. Copper layers 5, 6 can be produced by electroplating the steel foils. To improve the adhesion between epoxy core and metal foil, the surface structure of the copper layers can be roughened. The thickness of the copper layers is between 5 and 100 Vm; i.e., it must be at least of the order of the fiber diameter.

Fig. 2 shows other means for preventing fibers 2 from deforming the surface of steel foils 3, 4. For this purpose, a pure resin layer 7 without fibers is built into the center of laminate core 1 to absorb any mechanical stresses. The fiber-free resin later 7 should be located in the center of the laminate so that the flexural stiffness is not noticeably affected. As the laminates are pressed together, the resin must not become so liquid that the fiber layers 8, 9, 10 and 11, 12, 13, re...