PURPOSE: To contrive an improvement in corrosion resistance, by a method wherein an iron-zinc alloy coating is formed by projecting particles obtained by cladding an iron-zinc alloy around nucleuses of iron or an iron alloy on at least a part of the surface of a steel material and a resin coating is formed by performing chromate treatment to the coating.
CONSTITUTION: A coating layer 1 is formed by spraying strongly particles 2 obtained by cladding an iron-zinc alloy around nucleuses of microscopic iron or an iron alloy against the surface of a steel material 3 and moving the iron-zinc alloy on the external circumference of the particles to the surface of the steel material. Then water system chromate treatment is performed for which a water solution containing, for example, 0.1W50g/l of a chromic acid compound and 0.01W5g/l of sulfuric acid is used. Then a coating 5 such as urethane resin or tar epoxy resin or polyethylene resin is applied to the whole area or only a splash zone of the steel material. In addition, at the time of application of the coating to the same, it is preferable to form an appropriate substrate treatment layer 4 on a lower layer 1. It is good that in the case, for example, of the urethane resin, airless painting of urethane primer of an extent of 25μm is thickness is performed and that in the case, for example, of the polyethylene resin, polyethylene adhesive resin of an extent of 150μm in thickness is stuck through heating. In the case of the tar epoxy resin, the substrate treatment is unnecessary.
NAKAZATO TAKUZO
SHIOTANI CHITOSE
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