| 摘要 |
To form a printed circuit panel, a metal component in the form of a thin metal foil is bonded to a flat plate of devitrified glass-ceramic or of a glass capable of controlled devitrification and the bonded element heat-treated to convert the glass to glass-ceramic. The metal foil may be of copper or copper alloy, silver or silver alloy or nickel; the copper or silver may be coated with a thin layer of nickel and the copper or nickel given a thin layer of the corresponding oxide. As described, the metal foil is pressed on the base of a mould, which base may be porous and the foil held by suction, and molten glass poured on the foil and either pressed by a die or rolled. The mould is of cast-iron or steel so that the foil is not melted by the heat of the glass. The resulting element is annealed and heat treated to devitrify the glass, treatment for copper being in an atmosphere of nitrogen. The preferred glass composition is in weight percentages SiO2 50-80; PbO 0-30; Al2O3 0-3; ZnO 5-30; Li2O 5-15; B2O3 0-7; K2O 0-5; Na2O 0-5; P2O5 1-3. |
