Self-cleaning colloidal slurry composition and process for finishing a surface of a substrate

Abstract

A self-cleaning colloidal slurry and process for finishing a surface of a glass, ceramic, glass-ceramic, metal or alloy substrate for use in a data storage device, for example. The slurry comprises a carrying fluid, colloidal particles, etchant, and a surfactant adsorbed and/or precipitated onto a surface of the colloidal particles and/or substrate. The surfactant has a hydrophobic section that forms a steric hindrance barrier and substantially prevents contaminates, including colloidal particles, from bonding to the substrate surface. The slurry is applied to the surface of the substrate while a pad mechanically rubs the surface. Subsequent cleaning with standard soap solutions removes substantially all remaining contamination from the substrate surface. In an exemplary embodiment, the slurry is used to superfinish a glass disk substrate to a surface roughness of less than 2 Å, with substantially no surface contamination as seen by atomic force microscopy (AFM) after standard soap cleaning steps.

1 . A disk substrate for use in a data storage device, the disk substrate comprising: 
 substrate material having a surface roughness of less than 2 Å; the substrate material being selected from a group consisting of glass, ceramic, and glass-ceramic; and the substrate material having essentially no surface contamination even though the surface of the substrate material was not subjected to a cleaning process that utilized etching or micropolishing or cleaning polish etch, or a combination thereof, to remove contaminants therefrom.    
     
     
         2 . The disk substrate as recited in  claim 1 , wherein the substrate material is a silicate-based glass.  
     
     
         3 . The disk substrate as recited in  claim 1 , wherein the disk substrate is made utilizing a process for superfinishing a surface of a substrate, the process comprising the steps of: 
 applying a self-cleaning colloidal slurry to the surface of the substrate, the self-cleaning colloidal slurry comprising 
 a carrying fluid,  
 colloidal particles,  
 etchant for etching the substrate,  
 a surfactant adsorbed and/or precipitated onto a surface of at least one of the substrate and the colloidal particles, the surfactant having a hydrophobic section that forms a steric hindrance barrier between the substrate and the colloidal particles;  
   mechanically rubbing the surface of the substrate with a pad while contacting the surface of the substrate with the self-cleaning colloidal slurry.    
     
     
         4 . A data storage disk for use in a data storage device, comprising: 
 a disk substrate comprising a substrate material having a surface roughness of less than 2 Å; the substrate material being selected from a group consisting of glass, ceramic, and glass-ceramic; and the substrate material having essentially no surface contamination even though the surface of the substrate material was not subjected to a cleaning process that utilized etching or micropolishing or cleaning polish etch, or a combination thereof, to remove contaminants therefrom;    a recording layer applied over at least one surface of the disk substrate.    
     
     
         5 . The data storage disk as recited in  claim 4 , wherein the substrate material is a silicate-based glass.  
     
     
         6 . The data storage disk as recited in  claim 4 , wherein the disk substrate is made utilizing a process for superfinishing a surface of a substrate, the process comprising the steps of: 
 applying a self-cleaning colloidal slurry to the surface of the substrate, the self-cleaning colloidal slurry comprising 
 a carrying fluid,  
 colloidal particles,  
 etchant for etching the substrate,  
 a surfactant adsorbed and/or precipitated onto a surface of at least one of the substrate and the colloidal particles, the surfactant having a hydrophobic section that forms a steric hindrance barrier between the substrate and the colloidal particles;  
   mechanically rubbing the surface of the substrate with a pad while contacting the surface of the substrate with the self-cleaning colloidal slurry.    
     
     
         7 . A data storage device, comprising: 
 a data storage disk comprising a disk substrate, the disk substrate comprising a substrate material having a surface roughness of less than 2 Å; the substrate material being selected from a group consisting of glass, ceramic, and glass-ceramic; the data storage disk further comprising a recording layer applied over at least one surface of the disk substrate; and the substrate material having essentially no surface contamination even though surface of the substrate material was not subjected to a cleaning process that utilized etching or micropolishing or cleaning polish etch, or a combination thereof, to remove contaminants therefrom;    a transducer;    an actuator provided to position the transducer relative to the data storage disk;    a motor provided to rotate the storage disk relative to the transducer.    
     
     
         8 . The data storage device as recited in  claim 7 , wherein the substrate material is a silicate-based glass.  
     
     
         9 . The data storage device as recited in  claim 7 , wherein the disk substrate is made utilizing a process for superfinishing a surface of a substrate, the process comprising the steps of: 
 applying a self-cleaning colloidal slurry to the surface of the substrate, the self-cleaning colloidal slurry comprising 
 a carrying fluid,  
 colloidal particles,  
 etchant for etching the substrate,  
 a surfactant adsorbed and/or precipitated onto a surface of at least one of the substrate and the colloidal particles, the surfactant having a hydrophobic section that forms a steric hindrance barrier between the substrate and the colloidal particles;  
   mechanically rubbing the surface of the substrate with a pad while contacting the surface of the substrate with the self-cleaning colloidal slurry.