Overvoltage of hydrogen release on zirconium, titanium, and tantalum nitrides in 1N H$sub 2$SO$sub 4$

Nitride samples were obtained by high-temperature surface nitridation of Ti at 1400 deg , Zr at 1700 deg , and Ta at 1900 deg for 4 h. Nitridation on one side of the sample occurred at depths of 50 to 70 mu . The overvoltage of H/sub 2/ release was studied by plotting the polarization curves using the potentiostatic methed. It was established that the stationary potential of TiN and TaN oscillates in the limits of plus or minus 150 mV. For stabilization of the surface of electrodes from these materials, a preliminary etching for 2 to 3 s in 5% Hf proved effective. Tests show that short-time processing in HF does not affect the pattern of the cathode polarization curves. Samples of ZrN were etched in 20% H/sub 2/SO/sub 4/ for 1 to 1.5 min and a part was subjected to a preliminary cathode polarization. (tr-auth)