| 摘要 |
PURPOSE:To provide an iron-phosphorus electroplating bath which yields a crack-free film having excellent mechanical characteristics by consisting essentially the bath of bivalent ion iron and phosphorous acid and/or phosphite. CONSTITUTION:An iron-phosphorus electroplating bath contains 20-80g bivalent iron ion for which ferrous sulfate or the like is used as a supply source and 0.01-20g, more particularly 0.1-10g phosphorous acid and/or phosphite (in the form of NaH2PO3.2H2O) for each 1l of the plating bath. The iron-phosphorus plating film having usually 0.05-10% phosphorus content is obtd. by changing the content of phosphorous acid or phosphite in such plating bath. Ammonium sulfate, etc. may be further added as electrical conductivity salt to the plating bath at 0-200g/l, boric acid, etc. as a pH buffer at 0-60g/l, acidic ammonium fluoride, etc. as a complexing agent for tri-valent iron ion at 0-20g/l. The bath temp. in the stage of using the plating bath is made room temp. -80 deg.C, pH 0.5-3.5 and cathode current density 0.5-30A/dm<2>.
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