Protective Action of Electroplated Deposits and Paint Films in Corrosive Gases

To evaluate various surface treatment processes for apparatus, we carried out field exposure tests on electroplated deposits and painted films under the conditions of fertilizer, soda and other chemical plants, covering the period of 2.5 years from August, 1959. Concurrently we also carried out experiments on protective behavior of coatings by electroplating and painting in corrosive gases in our laboratory. Results obtained are summarized as follows: 1) Coatings of zinc, chromium and silver are effective for corrosion prevention in sulfur dioxide gas, and chromium is effective in hydrogen sulfide gas. 2) Coatings of paints of phenolic resin, vinyl resin and high solid lacquer type are effective against sulfur dioxide gas, and each paint of lacquer, vinyl and vinyl alkyd type against hydrogen sulfide gas. 3) From the results obtained at a laboratory,. the adequacy and effective life of surface treatmentt in actual exposure state may be estimated to a certain extent.