A low-power nitriding technique utilizing a microwave-excited radical flow

Abstract

We report a novel low-power nitriding technique by utilizing a 2.45 GHz microwave-excited nitrogen radical flow system. Nitrogen plasma was produced at the nozzle with dimensions of 50 × 0.5 mm2 and blown onto the surface of a target substrate. A titanium substrate has been used as a target plate since it is easy to visualize a nitriding effect. The titanium substrate was treated under the conditions of 60 W microwave power, 20 Torr of nitrogen gas pressure, and a plate temperature of ∼800 °C. As a result, we have succeeded in nitriding of the titanium substrate in a quasi-atmospheric region of 20 Torr and of a very low power of 60 W with the hardness kept high, which is almost the same as the hardness processed by conventional nitriding methods.