Titanium nitride coatings to inner wall of narrow tube

Abstract

Titanium nitride (TiN) shows considerable hydrogen impermeability and is expected as a hydrogen-impermeable coating of cladding tubes for metal hydride fission fuel. The TiN coating production by the plasma process is very complicated because the cladding tube is not wide enough to create stable plasma. In this study, a simple reactive evaporation process was employed for the coating process of TiN films on the inner wall of a narrow tube. The films were thermally deposited on stainless steel sheets as the substrate and were coiled around the inner wall of silica glass tubes. A Ti wire twisted with a Mo filament was used for the evaporant. As a result, thin films with gold color were obtained. From the XRD measurement of the films, distinct diffraction patterns of TiN phase were observed. A reactivity of N2 gas molecules with Ti atoms in Ti-N film formation was measured quantitatively. The reaction probability of N2 molecules rN2 is defined as the ratio of the N2 absorption rate AN2 on Ti to the rate of N2 impingement ZN2. Reactive evaporation process showed 013 . 0 2 ≅ N r . It was 1/5