| 摘要 |
Dull, black Cr can be electrodeposited at pref. 10-30 A/sq. dm. and 17-30 degrees C from sulphate-free acid baths containing Cr (VI) cpds. and 3-100 g/1 phosphoric acids or their salts (concn. calc. as free acids). Surfaces coated include bright Ni-plated objects. Process is useful in car and instrument prodn. - Pref. bath additives include: HF,HBF4 or H2SiF6; (in) organic N cpds., mono- and/or polycarboxylic acids; lanthanides, BaCO3, Cr(III) cpds. and wetting agents.
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