US2064307A - Zinc plating anode - Google Patents

Description

9 anode films and sludge.

Patented Dec. 15, 1936 zmo PLATING ANODE George B. Hogaboom, New Britain, Conn, assigner to Hanson-Van Winkle-Manning Company, Matawan, N. Jersey J., a corporation of New No Drawing. Application February 29, 1936, Serial No. 66,447

8 Claims.

This invention relates to anodes for the electrodeposition of zinc from either acid or alkali cyanide solutions, and has for its object to improve the action of the anode, the operation of the bath,

and the character of the deposit.

I have discovered that the addition of a small quantity of nickel to a zinc anode results in a marked improvement in the features above mentioned, and in other respects as well. Such improvement is noted when nickel is added to either a straight zinc anode or one which contains'mercury or aluminum or both mercury and aluminum. Anodes of these respective ingredients are well-known in the art. Certain difliculties have occasionally arisen in the use of zinc anodes containing mercury or mercury and aluminum, and in these cases the addition of a small quantityof nickel to the zinc anode offers the important advantage of eliminating certain objections to the inclusion of mercury in the alloy.

The desirable amount of nickel to include in the anode is quite variable but need not be high. For example, from .1 to 1.0% nickel constitutes a satisfactory range in most respects in combination with from 99.90 to 99.00 zinc. This same percentage of nickel is satisfactory with .5 to 1.0% aluminum and the balance zinc, or with .5 to 1.0% aluminum, .1 to .3% mercury, and the balance zmc. In making the anodes, any approved metallurg'ical operation may be followed, and as an example I may mention the fusion of the nickel and zinc or nickel aluminum and zinc in proper proportions followed by casting, to produce a zinc nickel or zinc aluminum nickel anode. To produce a zinc mercury nickel or a zinc aluminum mercury nickel anode, the zinc and nickel or zinc aluminum andnickel may be fused together in a suitable furnace and then removed and allowed to cool to a temperature still above the freezing point of the alloy, when the mercury may then be added and the mixture or alloy cast in molds. This procedure is preferred to reduce the loss of mercury by evaporation.

Anodes thus produced possess a very fine grained structure, and will operate at high current density in either acid or alkali cyanide plating baths of standard practice without being subject to serious polarization or the production of insoluble I The deposits obtained are of exceptionally fine grained structure and are free from treeing and pitting, and do not contain loosely adhering particles.

' The usual baths may be satisfactorily operated at cathode current densities up to 80 amperes per square foot at from room temperature to 140 F. Successful and satisfactory performance has been noted at much higher cathode current densities than 80 amperes per square foot, and with con cipal component stant temperature and agitation of the work and the solution, such as in electroplating moving wire or strip, or in barrel plating, cathode current densities as high as 500 amperes per square foot have been perfectly feasible and practical.

While I have mentioned the use of these anodes in the standard electroplating baths or solutions, I wish further to point out that zinc anodes containing nickel, of the types described, are found to be very satisfactory for use in a number of socalled bright plating solutions, and. particularly the bright plating solutions set forth and described in the U. S. application of Vincent Mattacotti, filed September 28, 1935, Serial No. 42,671. The fact that the anodes show a surprising freedom from serious anode polarization at very high current densities renders them especially advantageous for use in connection with the modern developments in electrogalvanizing ferrous metal wire and strip moving at high speed through the plating apparatus.

I do not wish to be confined to any exact proportions of the ingredients employed in the anode, as these proportions are not really critical and may be departed from to a reasonable extent without sacrificing the benefits obtained by the inclusion of nickel in the anodes.

I claim:-

1. A zinc plating anode containing as a principal component zinc and in addition thereto a small percentage of nickel.

2. A zinc plating anode containing as a principal component zinc and in addition thereto small percentages of nickel and mercury.

3. A zinc plating anode containing as a prinzinc and in addition thereto small percentages of nickel and aluminum.

4. A zinc plating anode containing as a principal component zinc and in addition thereto small percentages of nickel, mercury and alumi num.

5. A zinc plating anode cipal component zinc and in addition thereto from .1 to approxi ately 1.0% nickel.

6. A zinc plating anode containing as a principal component zinc and in addition thereto from .1 to approximately 1.0% nickel, and from .5 to approximately 1% aluminum.

'7. A zinc plating anode containing as a principal component zinc and in addition thereto from .1 to approximately 1.0% nickel, and from .1 to approximately .3% mercury.

, 8. A zinc plating anode containing as a principal component zinc and in addition thereto from .1 to approximately 1.0% nickel, from .1 to approximately .3% mercury, and from .5 to approximately 1% aluminum.

GEORGE B. HOGABOOM.

containing as a prin-.