Abstract
Carbon-fiber reinforced plastics which have been used as strong and high elastic modulus materials for light-weight structures can be utilized in new areas by coating a metal on their surface.
A copper electroplating method was examined for the metal coating, since the electric conductivity of carbon-fibers in the composite materials appeared to be good enough for this purpose.
The results obtained for the epoxide resin reinforced anisotropically with about 60vol% continuous carbon-fibers are as follows:
(1) Carbon-fiber reinforced plastics can be electroplated with copper under the almost same condition for usual metals in copper sulfate or copper pyrophosphate bath. The deposition of initial grains of copper occurs on carbon-fibers at the surface of the reinforced plastics. A certain thickness of the electroplated layer is necessary for covering the whole surface of the reinforced plastics.
(2) The adhesive force of the electroplated layer increases with increasing roughness of the substrate surface. In copper sulfate bath, a large adhesive force is obtained when the layer is electroplated at a low current density or at high temperatures. The smoothness of the electroplated surface decreases under the condition that a large adhesive force is obtained.
(3) The adhesive force increases extremely without a large increase of roughness of the plated surface by the chemical pretreatment such as immersing the substrate in conc. sulfuric acid or chromic acid mixture. The increase of adhesive force is due to the increase of surface area, activity and cleanness of carbon-fibers at the surface and to the anchor effect of penetrating sections of the plated layer.
