Method of forming an electroforming mandrel

A process for making a nickel coated cylindrically shaped hollow core mandrel suitable for chromium coating for use in an electroforming process for the production of endless seamless nickel xerographic belts comprising:

• a. providing a cylindrically shaped hollow core member consisting essentially of a material selected from the group consisting of aluminum and aluminum alloys;
• b. establishing an anodizing zone comprising a metal cathode selected from the group consisting of lead and lead alloys and an anode comprising said core member, said cathode and said core member anode being separated by an anodizing bath maintained at a temperature of 78 to 80.degree. F. and after said core member anode has been exposed to said bath from 1 to 3 minutes without any voltage applied then gradually applying a voltage of 15 to 17 volts over a period of about 10 to 20 minutes to said anodizing bath, while imparting sufficient agitation to said anodizing bath to continuously expose said core member anode to fresh anodizing bath, maintaining said anodizing bath within said zone at a stable equilibrium composition comprising:
• H.sub.3 po.sub.4 at 2.7 to 3.7 parts concentrated H.sub.3 PO.sub.4 to 6.3 to 7.3 parts H.sub.2 O
• c. removing said core member anode from said anodizing bath while said voltage of 15 to 17 volts is being applied to said anodizing bath and then rinsing said core member anode with water sufficiently to remove said anodizing bath solution from said core member anode;
• then
• d. establishing a nickel electroforming zone comprising a metal anode selected from the group consisting of nickel and nickel alloys and a cathode comprising said core member, said core member cathode and said metal anode are separated by a nickel bath maintained at a temperature of 132.degree. to 138.degree. F. and having a ramp current when the core member cathode enters said nickel bath of from 10 to 20 amps per square feet and a voltage of 3 volts and increasing said ramp current over a period of at least 5 seconds to a ramp current of from 75 to 150 amps per square feet while imparting sufficient agitation to said nickel bath to continuously expose said core member cathode to fresh nickel bath, maintaining said nickel bath within said nickel electroforming zone at a stable equilibrium composition comprising:
• total nickel 9 to 11 oz/gal
• halide as NiX.sub.2.6H.sub.2 O -- 1.0 to 1.4 oz/gal wherein X is selected from the group consisting of chlorine, iodine and bromine,
• H.sub.3 bo.sub.3 at 4.8 to 5.2 oz/gal
• continuously maintaining the surface tension of the nickel bath at 33 to 42 dynes per cm;
• e. removing said core member cathode from said nickel bath while still imparting sufficient agitation to said nickel bath to continuously expose said core member cathode to fresh bath and then rinsing said core member cathode with water sufficiently to remove said nickel bath solution from said core member cathode.