| 摘要 |
PROBLEM TO BE SOLVED: To provide water for removing the oxide film or rust of metal without using highly harmful specified chemical substances, and to provide a method for removing the oxide film or rust of metal using the water. SOLUTION: Acid water obtained by electrolyzing raw water comprising 20 to 20,000mg/L sulfuric acid ions, and having pH of 0.5 to 4.0, a residual chlorine concentration of≤10mg/L, an oxidation-reduction potential of 300 to 1,150mV, a sulfuric ion concentration of 30 to 30,000mg/L and an electrical conductivity of≤10S/m is used. Further, ultrasonic vibration is applied to the acid water, so that the removal of an oxide film can be performed with high quality in a short period of time. COPYRIGHT: (C)2004,JPO
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