An electrically conductive connector housing body (16, 17) of aluminum or an aluminum compound, and a surface layer on the aluminum which comprises an adhesive layer in the form of a chemical nickel-plating, a corrosion protection layer, and a metallic passivation layer provided in sequence. In order to avoid the use of toxic metals and their compounds in a housing part of this type and nevertheless to assure sufficient conductivity and corrosion resistance, the corrosion protection layer is formed by a zinc-cobalt-iron compound, the passivation layer is constituted by a compound made of trivalent chromium, and a sealing layer made of an inorganic compound containing silicate is applied as the exterior layer.