Methods for forming an electrolytic deposit containing molybdenum on a support and the products obtained thereby

Claim 1

An electrolytic method for producing, on an electrically conductive support, a codeposit layer of molybdenum and at least one transition metal selected from the group consisting of Ni, and Co, in which the support to be protected is at the cathode and the bath in which this cathode is immersed contains at least one compound of molybdenum and at least one compound of said transition metal, said method comprising, providing in the bath an aqueous soluton of: an alkali metal molybdate at a concentration from 0.008 M/l to 0.05 M/l, a salt of said transition metal and an alkali-metal salt of an organic acid with mixed acid-alcohol functional groups, said salt being capable of giving complexes with the molybdenum and transition metal ions of the other constituents, adjusting the pH of the bath between 9 and 11 and maintaining the temperature of the bath at a temperature above 20°C compatible with the stability requirements of said complexes, using a cathodic current density greater than 5 A/dm 2 , pursuing the electro-deposition treatment for a duration which is less than a threshold, called "scaling duration", above which there is produced a scaling of the deposit formed, said threshold being a decreasing function of the thickness of said layer, and subjecting said layer of alloy and the sub-adjacent support to a thermal treatment conducted in a non-oxidizing medium, at a temperature between 700°C and 1200°C and compatible with the preservation of the properties of said support, the duration of this thermal treatment being between 2 and 24 hours.