Thesis (Ph.D.)--Chulalongkorn University, 2010

RF-ICP plasma nitriding is used to improve surface property by producing a nitride layer on the specimen. The main aim of this work is to form the nitride layer on the surface of Al alloy and AISI H13 by RF-ICP plasma nitriding with the treatment temperature lower than 350 oC. The specimens were plasma nitrided at different treatment times while the rf-power, working pressure and treatment temperature were kept constant. After plasma nitriding, the nitride layers including AlN, FeN were present in the aluminium alloy sample and H13 sample, respectively, as detected by X-ray diffraction analysis. In the case of the Al alloy, the hardness of the nitrided sample is difficult to measure because of the thin layer of nitride on the sample surface and high roughness. Moreover, the thick AlN did not form when we varied the parameters including the type of gas sputtering, treatment time, and gas pressure. Therefore, we can conclude that rf plasma nitriding is not suitable for aluminium alloys. On the contrary, in the rf plasma nitriding of H13, the thickness of the nitride layer reaching more than 150 µm was achieved for 20 hours with the hardness as high as 1072 HV.