What is claimed is:
1. A process for the electrodeposition of a nickel-chromium alloy on a cathodic substrate, comprising:
contacting the substrate with an aqueous electrolyte containing: about 50-125 g/l of CrCl.sub.3.6H.sub.2 O; about 10-125 g/l of NiCl.sub.2.6H.sub.2 O; about 10-115 g/l of formic acid; about 25-50 g/l of boric acid; and about 50-100 g/l of sodium citrate dihydrate;
adjusting the pH of the bath to about 1-5 and the temperature to about 20.degree.-60.degree. C.; and
passing a sufficient current through the solution and to the substrate to effect deposition thereon of a nickel-chromium alloy.
2. The process of claim 1, wherein said electrolyte contains up to about 75 g/l of glycolic acid.
3. The process of claim 1, wherein said electrolyte contains up to about 20 g/l of sodium bromide or ammonium bromide.
4. The process of claim 1, wherein said electrolyte contains up to about 75 g/l of ammonium chloride.
5. The process of claim 1, wherein said temperature is about 35.degree. C.
6. The process of claim 1, wherein said pH is about 3.5.
7. The process of claim 1, wherein said current is direct current.
8. The process of claim 1, wherein said current is a pulsed current.
9. the process of claim 8, wherein the period is 0.05-10 milliseconds; the duty cycle is 20-80%; the base height is -10-+10 A/dm.sup.2 ; and the peak height is 5-100 A/dm.sup.2.
10. The process of claim 1, wherein said nickel-chromium alloy deposit is at least about 75 microns thick.
11. The process of claim 1, wherein the chromium content of said nickel-chromium alloy deposit is at least about 20% by weight.
12. An aqueous electrolyte for electroplating nickel-chromium alloys by electrodeposition, consisting essentially of an aqueous solution containing: about 50-125 g/l of CrCl.sub.3.6H.sub.2 O ; about 10-125 g/l of NiCl.sub.2.6H.sub.2 O; about 10-115 g/l of formic acid; about 25-50 g/l of boric acid; and about 50-100 g/l of sodium citrate; said solution having a pH of 1-5.
13. The electrolyte of claim 12, which further contains up to about 75 g/l of glycolic acid.
14. The electrolyte of claim 12, which further contains up to about 20 g/l of sodium bromide or ammonium bromide.
15. The electrolyte of claim 12, which further contains up to about 75 g/l of ammonium chloride.
16. The electrolyte of claim 12, having a pH of 3.5.