A study on rf plasma nitriding at a constant power in different H2–N2 mixtures at different temperatures

Austenitic stainless steel AISI 304 has been nitrided by radio frequency (rf) plasma containing various nitrogen–hydrogen gas mixtures, in order to study the effect of hydrogen on structure and magnetic properties of the formed compound layer. The thermal temperature has been measured at the vicinity of the samples. The compound layer thus produced has been characterized using, X-ray diffractometer and vibration sample magnetometer. Providing the total pressure of nitrogen and hydrogen is held constant, the addition of hydrogen up to 50% gives new structural phases. The magnetization values of the plasma treated samples are strongly dependent on the percentage of H2 in the gas phase. An excessive amount of hydrogen (∼75%) on the other hand, retards the nitriding process. The surface temperature of the sample and plasma condition is crucial factors for nitriding process.