Abstract: The present invention provides metal surface treatment agents and metal surface treatment methods which can form a high anticorrosion coating without use of hexavalent chromium compounds which are a cause of environmental pollution. In the present invention, a metal surface is coated with a metal surface treatment agent made of a composition containing a compound containing at least one or more mercapto groups per molecule and, depending upon need, a curing agent, curing catalyst and/or silica and the coating of the metal surface treatment agent is heat-treated.

Abstract: An improved anticorrosion coating composition is disclosed. The composition is characterized in that in the known anticorrosion coating composition comprising a chromic acid compound or a chromic acid compound and a boric acid compound, a powder of zinc, aluminum of an alloy of a mixture thereof, a (poly)glycol compound and solvent, a part of chromic acid compound ingredient is replaced by a water-soluble nickel and/or cobalt compound. The composition exhibits a better corrosion protection performance in more severe corrosion environment than the known anticorrosion coating composition with lesser content of harmful hexavalent chromium.