Friction material and manufacturing method thereof

Abstract

A friction material is provided with a matrix fiber, a binder, and a filler. The friction material contains a stabilized zirconia having a lattice constant in a range from 99.93 to 99.95% as compared with a lattice constant of a single crystal of stabilized zirconia. The lattice constant scarcely changes, since the stabilized zirconia contained in the friction material undergoes less introduction of distortions when used under severe conditions. Accordingly, the stable friction characteristic with less change of the friction coefficient in the initial stage of using the brake can be obtained.

1 . A friction material comprising:
 a matrix fiber;   a binder;   a filler; and   a stabilized zirconia having a lattice constant in a range from 99.93 to 99.95% as compared with a lattice constant of a single crystal of stabilized zirconia.   
     
     
         2 . The friction material according to  claim 1 , wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1253 to 5.1263 Å. 
     
     
         3 . A friction material comprising:
 a matrix fiber;   a binder; and   a filler, wherein a stabilized zirconia having a lattice constant in a range from 99.95 to 99.97% as compared with a lattice constant of a single crystal of stabilized zirconia is utilized as a compound in the filler.   
     
     
         4 . The friction material according to  claim 3 , wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1263 to 5.1275 Å. 
     
     
         5 . A method of manufacturing a friction material comprising:
 uniformly mixing a matrix fiber, a binder, and a filler; and   molding a mixture of the matrix fiber, the binder, and the filler under heating and pressure,   wherein a stabilized zirconia having a lattice constant in a range from 99.95 to 99.97% as compared with a lattice constant of a single crystal of stabilized zirconia is utilized as a compound in the filler.   
     
     
         6 . The method according to  claim 5 , wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1263 to 5.1275 Å.