Appeal No. 2007-1530 Application 10/095,112 While attempting to produce a substrate that is lower in weight, higher in electrical conductivity, tougher and harder than its aluminum predecessors, the Al—B—C ceramic is excellent. Its density is lower than the others, its electrical conductivity nearly rivals pure metallic aluminum, its stiffness is excellent, its fracture toughness is very good, and its hardness is more than satisfactory. As one can see, all the properties needed for a substrate are easily met or exceeded by the Al—B—C composite material. (Col. 8, ll. 22-29.) Thus, the electrical conductivity of the Al—B—C ceramic is described as “nearly rival[ling] pure metallic aluminum” (id.) even though aluminum’s conductivity exceeds that of the Al—B—C ceramic by more than an order of magnitude. High electrical conductivity and low density are also among the properties mentioned in the following summary of the properties of Pyzik’s composites: Accordingly, the present invention provides hard drive disk substrates, methods of making same, and materials made therefrom, wherein the material has a high hardness, a high wear resistance, a high fracture toughness, a high damping capability, a low density, and a high specific stiffness and is electrically conductive. In addition, the material forming the disk substrates exhibits unique combinations of properties, such as high stiffness and high toughness, high hardness and high strength, and high stiffness and high damping capability. Col. 13, ll. 3-12 (emphasis added). Pyzik’s composite material is also capable of being coated with a layer of metal, such as copper: “If a sub-surface (below the magnetic media layer) coating is desirable, the sub-surface material may be metal (e.g., chromium, nickel, cobalt, silicon, aluminum, copper, titanium, or magnesium), metal alloy, metal oxide, 10Page: Previous 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Next
Last modified: September 9, 2013