Cerium-based abrasive, abrasive slurry, and production of cerium-based abrasive

Abstract

There is provided a cerium-based abrasive containing cerium oxide as a main component, in which the abrasive particles composing the abrasive are coated with a coating layer containing at least either one of a silicon component of silicon or a silicon compound and an aluminum component of aluminum or an aluminum compound. The cerium-based abrasive can be produced by wet-dispersing the cerium-based abrasive in a dispersion medium to obtain a slurry and carrying out surface treatment by adding a treatment solution containing at least either one of the silicon compound and the aluminum compound to the slurry. Further, the cerium-based abrasive can be produced by carrying out surface treatment by adding a treatment solution containing at least either one of the silicon compound and the aluminum compound to the slurry during the pulverization step or after the pulverization step in the conventional cerium-based abrasive production process and after that roasting and classifying the obtained cerium-based abrasive.

1 . A method for polishing a glass by using a cerium abrasive, which contains cerium oxide as a main component, 
 wherein the cerium abrasive to be used in the method has an average particle diameter of 0.1 to 10 μm and has cerium oxide as a core, and wherein the core is coated with at least one coating layer consisting essentially of an inorganic silicon compound and an inorganic aluminum compound.    
   
   
       2 . The method for polishing a glass by using the cerium abrasive according to  claim 1 , wherein said coating layer of the abrasive particles is a single layer in which the inorganic silicon compound and the inorganic aluminum compound are mixed.  
   
   
       3 . The method for polishing a glass by using the cerium abrasive according to  claim 1 , wherein said coating layer of the abrasive particles has a double layer structure comprising a first coating layer coating the abrasive particles and a second coating layer coating the first coating layer, and said first coating layer is of the inorganic silicon compound, and said second coating layer is of the inorganic aluminum compound.  
   
   
       4 . The method for polishing a glass by using the cerium abrasive according to  claim 1 , wherein said coating layer has a double layer structure comprising a first coating layer coating the abrasive particles and a second coating layer coating the first coating layer, and said first coating layer is of the inorganic aluminum compound, and said second coating layer is of the inorganic silicon compound.  
   
   
       5 . The method for polishing a glass by using the cerium abrasive according to any one of  claim 1 , wherein a content of the inorganic silicon compound and the inorganic aluminum compound contained in the coating layer of the abrasive particles in total weight of silicon element and aluminum element is 0.01 to 5% of the weight of the abrasive particles.  
   
   
       6 . The method for polishing a glass by using the cerium abrasive according to  claim 1 , wherein a repose angle of the abrasive particles is 60 degrees or smaller.  
   
   
       7 . A method for producing a cerium abrasive, said abrasive being used in the method for polishing a glass according to  claim 1 , wherein the method for producing the cerium abrasive comprises the steps of producing a slurry by wet-dispersing the cerium abrasive in a dispersion medium and carrying out surface treatment by adding to the slurry a treatment solution containing at least either one of a silicon compound and an aluminum compound.  
   
   
       8 . The method for producing the cerium abrasive particles according to  claim 7 , wherein said dispersion medium contains water as a main component.  
   
   
       9 . The method for producing the cerium abrasive according to  claim 7 , wherein said silicon compound and said aluminum compound contained in the treatment solution are water soluble.  
   
   
       10 . The method for producing the cerium abrasive according to  claim 7 , wherein said treatment solution is added such that a content of silicon element and aluminum element in total is 0.01 to 5% of the weight of the cerium abrasive or an abrasive raw material in the slurry.  
   
   
       11 . The method for producing the cerium abrasive according to  claim 7 , wherein pH of the slurry is adjusted to be within a range of 2 to 10 after addition of the treatment solution to carry out the surface treatment.  
   
   
       12 . A method for polishing glass, comprising the step of: 
 polishing said glass with a cerium abrasive comprising a cerium oxide core coated with at least one coating layer, wherein said coating layer is selected from the group consisting of 
 a layer consisting essentially of an inorganic silicon compound and an inorganic aluminum compound,  
 a layer consisting essentially of an inorganic silicon compound, and  
 a layer consisting essentially of an inorganic aluminum compound;  
   wherein said cerium abrasive has an average particle diameter of 0.1 to 10 μm, and cerium oxide as a main component.    
   
   
       13 . The method of  claim 12 , wherein said cerium oxide core is coated with a single layer which consists essentially of an inorganic silicon compound and an inorganic aluminum compound.  
   
   
       14 . The method of  claim 12 , wherein said cerium oxide core is coated with two layers, one of said two layers consists essentially of an inorganic silicon compound, and the other of said two layers consists essentially of an inorganic aluminum compound.  
   
   
       15 . The method of  claim 12 , wherein the combined total weight of the silicon and aluminum elements in said layer consisting essentially of an inorganic silicon compound and an inorganic aluminum compound is 0.01 to 5% of the weight of the abrasive particle, the total weight of silicon elements in said layer consisting essentially of an inorganic silicon compound is 0.01 to 5% of the weight of the abrasive particle and the total weight of aluminum elements in said layer consisting essentially of an inorganic aluminum compound is 0.01 to 5% of the weight of the abrasive particle.  
   
   
       16 . The method of  claim 12 , wherein repose angles of the abrasive particles are 60 degrees or smaller.