Generation of ammonia during wear processes in adhesive wear of titanium

Abstract

We report a short note of preliminary and new experimental results that the generation of ammonia (i.e. nitrogen fixation) can occur on tribologically activated surfaces formed as a result of the frictional sliding of pure titanium when this is performed in a mixed gaseous environment of dinitrogen and dihydrogen at a total pressure of 6 × 10 -4 Pa. Gaseous ammonia, synthesized at the tribologically activated surface on the actual area of contact and/or on fine debris of wear elements with a size of the order of ten or a few tens of nanometers, was detected by analyzing the partial pressures for each species between amu 1 and amu 50 present in the environmental gases during the sliding friction: this analysis was performed using a quadrupole mass spectrometer (QMS). This process, however, depends on the mode of wear, i.e. it is expected to occur only under mild conditions of wear.