| 摘要 |
PURPOSE:To obtain an etching liquid which can remove only the magnetic layer without roughening an underlying Ni-P film by incorporating prescribed ratios of EDTA, hydrogen peroxide water, caustic alkali and water therein. CONSTITUTION:The EDTA, hydrogen peroxide water, caustic alkali and water are incorporated into the etching liquid. The volumetric concn. of the EDTA is 0.01-20%, the hydrogen peroxide 0.1-20% and the caustic alkali >=0.001M/l. The underlying Ni-P is roughened when the concn. of the EDTA is <=0.01. There is a problem in solubility if the concn. is >=20%. The effect of an etching characteristic decreases if the concn. of the hydrogen peroxide is 0.1% and a problem arises in workability at >=20%. There is not so much problem with the concn. of the caustic alkali and <0.01M/l is enough.
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