| 摘要 |
A bath for plating gold and gold alloys comprises an aqueous solution of a compound of the formula: M (E)m(AU(CN)2)n where M is a metallic element of Group IB, IIB, IIIA, IIIB, IVA or VIII of the Periodic Table, n is a numeral equal to the most stable valence of the metal M in aqueous solution, m is an integer from (n - 1) to (n + 1) and E is an amine of the formula: RR1NCH(R4) (CxH22)N R2R3 or RR1N(CH2CH2NR2)y R3 where x is 1 - 3, y is 1 - 4, R, R1, R2 and R3 are each hydrogen, hydroxymethyl or hydroxyethyl and R4 is hydrogen or straight chain alkyl having 1 - 4 carbon atoms, at least two of R, R1, R2, R3/t and R4 being hydrogen. Preferred aqueous electroplating baths contain about 5 dwt/gal to 30 dwt/gal of metallic gold in the form of one of the above compounds, about 200 - 600 gms/gal of dipotassium phosphate and sufficient ammonium hydroxide to adjust the pH to about 8 - 12. The bath may also contain up to about 200 ml/gal of ethylenediamine. Preferred immersion chemical plating baths contain about 5 - 20 dwt/gal of metallic gold in the form of one of the above compounds, about 10 - 60 gms/gal of dipotassium phosphate, about 50 - 200 gms/gal of a complexing agent such as aminopolycarboxylic acids and their salts, a minor amount of a conducting salt and sufficient ammonia or ammonium hydroxide to adjust the pH to about 8 - 12. The plating baths may also contain other additives. In examples, plating baths comprising the following compounds are described: Ag(NH2CH2CH2NH2) (Au(CN)2), Cu(NH2CH2CH2NH2)2 (Au(CN)2)2, Pd(NH2CH2CH2NH2)2 (Au(CN)2)2, Zn(NH2CH2CH2NH2)3 (Au(CN)2)2.ALSO:The invention comprises compounds of the formula M(E)m(Au(CN)2)n, where M is a metallic element of Group Ib, IIb, IIIa, IIIb, IVa or VIII of the Periodic Table, n is a numeral equal to the most stable valence of the metal M in aqueous solution, m is an integer from (n-1) to (n+1) and E is an amine of the formula RR1NCH(R4)(CxH2x)NR2R3 or RR1N(CH2CH2NR2)yR3 where x is 1-3, y is 1-4, R,R1, R2 and R3 are each hydrogen, hydroxymethyl or hydroxyethyl and R4 is hydrogen or a straight chain alkyl having 1-4 carbon atoms, at least two of R, R1, R2, R3 and R4 being hydrogen. They may be obtained by admixing an amine, E, with potassium or sodium gold dicyanide in an aqueous solution containing cations of a metal, M. In examples the amine used is ethylene diamine, isopropylene diamine or tetraethylene pentamine and the metal, M, is Cu, Cd, Ni, Ag, Au or Pd. |
