Polishing kit for magnetic disk

Abstract

A polishing kit for a magnetic disk containing (A) a slurry containing an alumina, (B) an oxidizing agent solution containing an oxidizing agent, and (C) an acid agent solution containing an acid; a polishing kit for a magnetic disk containing (A) a slurry containing an alumina, and (D) an additive solution containing an oxidizing agent and an inorganic acid; and a polishing kit for a magnetic disk containing (A) a slurry containing an alumina, and (C) an acid agent solution containing an acid, wherein the polishing kit is used with an oxidizing agent solution (B) containing an oxidizing agent; and a polishing process for a magnetic disk substrate, including the steps of feeding a liquid mixture containing components of a specified polishing kit to a space between the magnetic disk substrate and a polishing cloth; and polishing the magnetic disk substrate with the liquid mixture. The polishing composition kit can be suitably used for the manufacture of high-quality magnetic disk substrates such as hard disks.

1 . A polishing kit for a magnetic disk comprising: 
 (A) a slurry comprising an alumina;    (B) an oxidizing agent solution comprising an oxidizing agent; and    (C) an acid agent solution comprising an acid.    
   
   
       2 . The polishing kit according to  claim 1 , wherein the alumina is α-alumina and θ-alumina, wherein the oxidizing agent is hydrogen peroxide, and wherein the acid is citric acid and sulfuric acid.  
   
   
       3 . A polishing kit for a magnetic disk comprising: 
 (A) a slurry comprising an alumina; and    (D) an additive solution comprising an oxidizing agent and an inorganic acid.    
   
   
       4 . The polishing kit according to  claim 3 , wherein the alumina is α-alumina and θ-alumina, wherein the oxidizing agent is hydrogen peroxide, and wherein the inorganic acid is sulfuric acid.  
   
   
       5 . The polishing kit according to  claim 3 , further comprising an acid agent solution (c) comprising an organic acid.  
   
   
       6 . The polishing kit according to  claim 5 , wherein the organic acid is citric acid.  
   
   
       7 . A polishing kit for a magnetic disk comprising: 
 (A) a slurry comprising an alumina; and    (C) an acid agent solution comprising an acid,    wherein the polishing kit is used with an oxidizing agent solution (B) comprising an oxidizing agent.    
   
   
       8 . The polishing kit according to  claim 7 , wherein the alumina is α-alumina and θ-alumina, wherein the acid is sulfuric acid, and wherein the oxidizing agent is hydrogen peroxide.  
   
   
       9 . A polishing process for a magnetic disk substrate, comprising the steps of: 
 feeding a liquid mixture comprising (A) a slurry comprising an alumina, (B) an oxidizing agent solution comprising an oxidizing agent, and (C) an acid agent solution comprising an acid to a space between the magnetic disk substrate and a polishing cloth; and    polishing the magnetic disk substrate with the liquid mixture.    
   
   
       10 . A polishing process for a magnetic disk substrate, comprising the steps of: 
 feeding a liquid mixture comprising (A) a slurry comprising an alumina, and (D) an additive solution comprising an oxidizing agent and an inorganic acid to a space between the magnetic disk substrate and a polishing cloth; and    polishing the magnetic disk substrate with the liquid mixture.    
   
   
       11 . The polishing process according to  claim 10 , wherein the liquid mixture further comprises (c) an acid agent solution comprising an organic acid.  
   
   
       12 . A method for manufacturing a polished magnetic disk substrate comprising the steps of: 
 (1) mixing (A) a slurry comprising an alumina, (B) an oxidizing agent solution comprising an oxidizing agent, and (C) an acid agent solution comprising an acid to give a polishing composition;    (2) pressing the magnetic disk substrate against a polishing cloth of a polishing platen while applying pressure; and    (3) moving the magnetic disk substrate and the polishing platen while feeding the polishing composition prepared in step (1) to a space between the magnetic disk substrate and the polishing cloth, thereby polishing the magnetic disk substrate.    
   
   
       13 . A method for manufacturing a polished magnetic disk substrate comprising the steps of: 
 (1) mixing (A) a slurry comprising an alumina, and (D) an additive solution comprising an oxidizing agent and an inorganic acid to give a polishing composition;    (2) pressing the magnetic disk substrate against a polishing cloth of a polishing platen while applying pressure; and    (3) moving the magnetic disk substrate and the polishing platen while feeding the polishing composition prepared in step (1) to a space between the magnetic disk substrate and the polishing cloth, thereby polishing the magnetic disk substrate.    
   
   
       14 . A method for manufacturing a polished magnetic disk substrate comprising the steps of: 
 (1) mixing (A) a slurry comprising an alumina, (D) an additive solution comprising an oxidizing agent and an inorganic acid, and (c) an acid agent solution comprising an organic acid to give a polishing composition;    (2) pressing the magnetic disk substrate against a polishing cloth of a polishing platen while applying pressure; and    (3) moving the magnetic disk substrate and the polishing platen while feeding the polishing composition prepared in step (1) to a space between the magnetic disk substrate and the polishing cloth, thereby polishing the magnetic disk substrate.