公开(公告)号：DE2944142A1

公开(公告)日：1980-05-29

申请号：DE2944142

申请日：1979-11-02

Applicant: IBM

Inventor： BARCLAY DONALD JOHN ,  LINFORD JAMES MICHAEL

IPC: C25D3/06

Abstract: The Cr concn. is 0.03M and is sufficiently weak to give a deposit whose colour is at least as bright as that of vapour deposited Cr. Bright Cr coatings can be formed (without the attendant problems of using Cr6+ baths) for decorative applications, and thick, coherent, smooth coatings can be formed for structural and mechanical applications. The ratio of the molar concns. of Cr/thiocyanate is pref. 1 : 2-4. The soln. pref. also contains an amino-acid (pref. aspartic acid) as buffer, in a molar concn. 1.25 times that of Cr. The bath temp. for a bright coating is pref. 40-60 degrees C, the brightest coloured coatings being formed using a current density >50 mA/cm2. The Cr concn. is pref. =0.02M. The pH of the bath is pref. 3.8 - 4.5.

公开(公告)号：MX153195A

公开(公告)日：1986-08-21

申请号：MX17997779

申请日：1979-11-09

Applicant: IBM

Inventor： BARCLAY DONALD JOHN ,  LINFORD JAMES MICHAEL

IPC: C25D3/06 ,  C25D5/14 ,  C25D3/10

Abstract: A very low concentration (below 0.03 M) trivalent chromium plating bath in which the source of chromium is an equilibrated aqueous solution of a chromium (III) - thiocyanate complex gives a deposit of unexpectedly light color. Such a bath is employed to produce thin overcoatings of light colored chromium for decorative applications. The bath and process is also used to plate the initial layer of a thick (greater than 5 micron) deposit for engineering applications, the major part of which is plated from a higher chromium concentration bath. Such thick deposits from a higher concentration bath are more cohesive and smoother when plated over an initial layer from the low concentration bath.