Electrodeposition of Metallic Boride Coatings.
McCawley-FX; Wyche-C; Schlain-D
U S Pat 3 697 390 1972 Oct; :
Borides of group IVA metals were deposited as smooth adherent electroplates of controllable thickness on conditioned substrate materials. A fused salt electrolyte mixture was prepared with the following composition: nabo2 39.1, Libo2 58.6, Na titanate 1.0, Li titanate 0.76, and tio2 0.55 pct. The ti content of this composition is 1.0 pct. The mixture was melted under an ar atmosphere to 850 deg. C after which a ti anode and mo cathode were inserted into the bath. A current density of 0.32 A/in2 was impressed for 2 h across the electrodes. The bath was agitated continuously by rotation of the cathode. The electrodes were raised from the bath and the cell was brought to room temperature. A deposit of finely divided dark powder was loosely attached to the cathode. This powder was identified as tib2 by x-ray diffraction analysis. The bath was heated to 900 deg. C under an ar atmosphere and a ti anode and inconel cathode were immersed in the bath with a C.D. of 0.41 A/in2 impressed for 2 h. Voltage across the electrodes was 0.31 V. The deposit was a bright adherent electroplate 1.5 Mils thick. Metallographic samples could be cut only with a diamond saw, indicating an extremely hard crystalline coating.
U.S. Pat. 3,697,390; Oct. 10, 1972; Chem. Abstr. 77:171,974Q