Nitriding Technique Research Articles

Condition of titanium and vanadium mononitride particles after nitriding and heat treatment

1. It was established that, in the initial condition, titanium and vanadium mononitride preparations produced by direct nitriding techniques are never in a state of equilibrium. The cross section of each grain has a nitrogen concentration gradient which may reach the limiting composition in the surface layer under certain nitriding conditions. 2. It is shown that, to obtain equilibrium preparations, specimens of the mononitrides must be subjected to additional annealing for several hours at 1200–1400°C under conditions precluding their further nitriding. 3. Using equilibrium specimens, the boundaries of existence of titanium and vanadium mononitrides at temperatures ranging from ∼800 to 1400°C were redefined with greater precision.

Nitride hardening of a molybdenum-titanium alloy by glow discharge

A cathode glow discharge unit has been constructed capable of heating small (3 mm diam.) disk specimens to 1450 °C. An alloy of molybdenum-0.96 wt.% titanium has been ion-nitrided at 1300 °C, and a two and a half times increase in the rate of nitriding has been observed compared with the rate obtained by conventional nitriding techniques. The method had a high penetrative power: nitriding took place equally on the lower surface of the disk in contact with the cathode as on the upper surface. The titanium nitride was observed to have precipitated with plate-like morphology with a {114} Mo habit plane.