Patent ID: 9612218
Date: 2017-04-04
CPC Classifications: B08B,C23G,G01N

Claim:
1. A method for determining whether an acidic aqueous solution is usable in pickling treatment that peels a coating layer on a surface of a member for a gas turbine, the method comprising: a first detection step of detecting a solution concentration of the acidic aqueous solution after the pickling treatment; a second detection step of detecting a concentration of a specific metal in the acidic aqueous solution after the pickling treatment, the metal being contained in the coating layer; a concentrated-solution addition step of newly adding a concentrated acidic aqueous solution when the solution concentration is equal to or less than a predetermined first threshold; and a determination step of determining that the acidic aqueous solution is unusable when the concentration of the specific metal is equal to or higher than a predetermined second threshold.