Abstract: The circumferential edges of glass or ceramic disks used in disk drive data storage devices are preferably finished by ductile grinding to produce an essentially fracture-free surface, which is not chemically strengthened. Preferably, the material is glass, and both the inner and outer edges of the disk are finished. Edge finishing is preferably achieved in a two-stage process, involving a coarse grind and a ductile grind, using air bearing spindles rotated at high speed for grinding wheels and workpiece. Preferably, the grinding wheels are shaped to provide a radius at the juncture of the circumferential edges and flat disk surfaces.

Abstract: This invention provides a disk which has an in-plane oriented magnetic recording layer on a glass, ceramic, or other nonmetallic substrate and a method for making the disk. A thin layer of texturable NiP is sputtered on the substrate. This NiP layer is textured before the magnetic layer is deposited. The disk combines all the advantages of a glass or ceramic substrate along with the advantages of an oriented magnetic medium.

Abstract: This invention provides a disk which has an in-plane oriented magnetic recording layer on a glass, ceramic, or other nonmetallic substrate and a method for making the disk. A thin layer of material is deposited on the substrate to form a texture stop layer. A texturable layer is then deposited on the texture stop layer. This texturable layer is textured before the magnetic layer is deposited. The disk combines all the advantages of a glass or ceramic substrate along with the advantages of an oriented magnetic medium.

Abstract: A thin film magnetic media structure with a pre-seed layer of CrTi is disclosed. The CrTi pre-seed layer presents an amorphous or nanocrystalline structure. The preferred seed layer is RuAl for use with the CrTi pre-seed layer. The use of the CrTi/RuAl bilayer structure provides superior adhesion to the substrate and resistance to scratching, as well as, excellent coercivity and signal-to-noise ratio (SNR) and reduced cost over the prior art. One embodiment of the invention sputter-deposits a CrTi pre-seed layer and a RuAl seed layer followed by at least one underlayer and at least one magnetic layer on a circumferentially polished substrate structure to achieve an Mrt orientation ratio greater than one. Two methods according to the invention allow the Mrt orientation ratio of the disk to be adjusted or maximized by varying the thickness of the RuAl seed layer and/or altering the atomic percentage of titanium in the pre-seed layer.

Abstract: A dressing disk for dressing and reconditioning the polishing pad of a planetary disk polishing machine is fabricated by plating a nickel/diamond matrix layer onto a stainless steel disk wherein the matrix layer thickness is developed or plated to a thickness which leaves exposed about 25 percent of the fine diamond particles, thereby forming a surface that has the look and feel of medium to coarse sandpaper. The dressing disks are inserted into the holes in a disk carrier of a planetary polishing machine and driven by its central rotary drive.

Abstract: The invention is a method for improving the flatness of nonmetallic substrates and preferably glass disks. The method comprises the steps of mounting the glass disk on a support. The support preferably comprises a refractory metal having a cooling rate substantially similar to the disk. The disk is then subjected to heating to a temperature in the anneal region for the given material for a period ranging from about 0.5 hours to 12 hours or longer, and then the disk is controllably cooled. The glass disk is preferably cooled at a rate of about 0.25.degree. C./minute to 1.5.degree. C./minute to room temperature. The invention also comprises a hard disk glass memory element and a data storage and retrieval device comprising this element.

Abstract: The lubricant film for a near contact magnetic recording device is maintained by a closed loop servo control for a recirculating lubricant supply system. A reservoir closely overlies the disk data surface and includes a heater for controlling the temperature difference between the reservoir and the disk surface. Decreasing the heater current reduces the film thickness and increasing the heater current increases the film thickness. A wick system gathers lubricant from within the disk enclosure, which may have been spun off the disk or condensed from the lubricant laden atmosphere and returns the lubricant by capillary action to the reservoir. Further, the reservoir includes two portions which are independently controllable. The first overlies the data band of the disk and the second overlies the start/stop zone and the head when the latter is not operational and parked at the nonoperating location.

Abstract: The lubricant film for a near contact magnetic recording device is maintained by a closed loop servo control for a recirculating lubricant supply system. A reservoir closely overlies the disk data surface and includes a heater for controlling the temperature difference between the reservoir and the disk surface. Decreasing the heater current reduces the film thickness and increasing the heater current increases the film thickness. A wick system gathers lubricant from within the disk enclosure, which may have been spun off the disk or condensed from the lubricant laden atmosphere and returns the lubricant by capillary action to the reservoir. Further, the reservoir includes two portions which are independently controllable. The first overlies the data band of the disk and the second overlies the start/stop zone and the head when the latter is not operational and parked at the nonoperating location.

Abstract: A rigid magnetic disk substrate is spin coated using a closely confining, stationary air barrier adjacent the surface being coated. The coating is applied through a slotted opening in the air barrier which is progressively closed as the coating is applied and completely sealed during the spin-off operation. During the application of the coating, the air barrier is positioned approximately 0.15 inch from the disk substrate surface and prior to spin-off, the barrier is moved to a position 0.025 inch from the coated surface. Further, during the high speed spin-off cycle a high kinematic viscosity gas, such as helium, is introduced into the space between the barrier and the coated surface to establish a laminar flow condition and eliminate spoking of the coated material.

Abstract: Disclosed is a circuit board and a process for the manufacture thereof providing a circuit board comprising a metal core having parallel first and second major faces and exhibiting high thermal and electrical conductivity. The circuit board includes electrical insulating layers of thermally conductive, dielectric material applied to the first and second major faces of the metal core. Protecting the dielectric layer and copper conductors is a solder mask layer applied to the dielectric layers and forming outward facing major surfaces. A plurality of insulated and grounded vias having electrically conductive interior rings connecting the major surfaces are provided through the board. Conductive sleeves within the vias are either electrically insulated from the metal core by dielectric material or in electrical contact to the metal core for grounding.