| Abstract |
| The effects of processing parameters on the surface properties of the hardened layers processed by the low temperature plasma nitrocarburizing and the low temperature two-step plama treatment (carburizing+nitriding) were investigated. The nitrogen-enriched expanded austenite structure (γΝ or S phase was formed on all of the treated surface. The surface hardness reached up to 1200 HV0.025, which is about 5 times higher than that of untreated sample (250 HV0.1). The thickness of hardened layer of the low temperature plasma nitrocarburized layer treated at 400℃ for 40 hour was only 15 μm, while the layer thickness in the two-step plama treatment for the 30 hour treatment increased up to about 30 μm. The surface thickness and hardness increased with increasing treatment temperature and time. In addition, the corrosion resistance was enhanced than untreated samples due to a high concentration of N on the surface. However, higher treatment temperature and longer treatment time resulted in the formation of Cr2N precipitates, which causes the degradation of corrosion resistance. |
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| Key Words |
| Low temperature plasma nitrocarburizing, expanded austenite, austenitic satinless steel, Low temperature plasma nitriding |
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