US Patent 7429418 - Porous friction material incorporating nanoparticles

http://www.freepatentsonline.com/7429418.html

This patent from BorgWarner teaches a new type of friction material for automotive applications based on nanoparticular material disposed in a porous material possessing improvements in heat resistance, high friction stability and durability, and strength compared to other materials. Claim 1 reads:

1. A friction material consisting essentially of:

a porous base material,

at least one resin material, and

nanoparticle-sized friction modifying particles dispersed within the porous base material,

wherein the nanoparticle-sized friction modifying particles are randomly dispersed within the friction material, wherein the nanoparticle-sized friction modifying particles are deposited on individual fibers and fillers comprising the porous base material at a thickness of about 0 to about 85 μm, wherein the friction material has substantially the same permeability in the radial direction and in the normal direction, wherein the nanoparticle-sized friction modifying particles have an average diameter size from about 10 nm to about 150 nm, wherein the porous base material has an average voids volume from about 65% to about 85%; and wherein the nanoparticle-sized friction modifying particles have an irregular shape.