PURPOSE: To make the velocity of dissolution proper and to enable automatic dissolving operation, by adding a compound having a specified phenolic hydroxyl group to a soln. contg. prescribed amounts of hydrogen peroxide and hydrofluoride ions or dihydrofluoride ions to prepare a chemical dissolving soln. for iron and iron alloys.
CONSTITUTION: A soln. contg. 1W350g/l hydrogen peroxide, ≥1g/l hydrofluoride ions or dihydrofluoride ions from acidic ammonium fluoride or the like, and ≥0.1g/l of at least 1 kind of compound having a phenolic hydroxyl group is used as a chemical dissolving soln. for Fe, Fe-Ni and Fe-Ni-Co alloys. Said compound having a phenolic hydroxyl group is represented by formula I (where X is H or -COOH), and phenolsulfonic acid, sulfosalicylic acid or the like is used as the compound. The soln. is treated at 10W80°C for 5secW30min by an immersion method, a spraying method or a rotary barrel method. The velocity of dissolution of Fe and Fe alloys is increased to such a degree that automation is enabled, and the dissolving work efficiency is improved.
IKETANI ITARU
IIDA SADAO
YAMAZAKI TOSHIHIKO
