A comparative study of the surface recombination of nitrogen atoms on various materials at atmospheric pressure

The surface recombination of nitrogen atoms on various materials was investigated at atmospheric pressure. The afterglows of pure nitrogen discharge are injected into a surface loss test unit, whose path wall is composed of the materials to be examined. Measurement of the nitrogen atom densities at several points in the flowing afterglows reveals the temporal decay characteristics. The results are compared with two-dimensional numerical simulations to obtain the surface loss probability γ. Among the seven materials we studied (stainless steel, aluminium, titanium, alumina, Pyrex glass, aluminium nitride and boron nitride), stainless steel was found to have the highest γ value: 1.8 × 10 −3 ; the lowest was for boron nitride: 4.8 × 10 −5 . The dependence of γ on surface roughness and temperature was also examined.