Single-Face Electrogalvanized, Chromium-Free Surface Treated Steel Plate for Fuel Tank and Surface Treatment Agent

摘要

The invention relates to an inorganic aqueous surface treatment agent for a single-face electrogalvanized, chromium free surface treated steel plate, a single-face electrogalvanized, chromium-free surface treated steel plate used for fuel tanks and a process of making the same. The inorganic aqueous surface treatment agent for a single-face electrogalvanized, chromium free surface treated steel plate comprises the following components: one or more metallic ion compounds comprising at least one of Zn²⁺, Mn²⁺, Mg²⁺, Ni²⁺, Al³⁺ and Ca²⁺; one or more vanadium compounds comprising at least one of V⁴⁺ and V⁵⁺; one or more compounds comprising at least one of phosphoric acid, pyrophosphoric acid, metaphosphoric acid, organic phosphoric acid and the ammonium salts thereof; one or more fluoric acid compounds comprising at least one of Zr, Ti, Si and Ha; one or more silane coupling agents comprising at least one of vinyl silane coupling agent, amino silane coupling agent, epoxy silane coupling agent and acryloxy silane coupling agent; a silica sol having a particle diameter less than 100 nm; one or more surfactants comprising at least one of carboxylate, sulfuric acid ester salt, sulfonate and phosphoric acid ester sa wherein the total solid content in the inorganic aqueous surface treatment agent is 2 wt %-20 wt % of the surface treatment agent. The process for preparing the single-face electrogalvanized chromium-free surface treated steel plate used for fuel tanks comprises the steps of coating the plated surface of the single-face electrogalvanized steel plate with the above surface treatment agent, solidifying at a temperature of 70-100° C., and finally oil finishing on the surface to produce a skin film resulting from the surface treatment with a weight of 100-600 mg/m².