This study aimed to address the limitations of traditional plasma nitriding methods by implementing a short-term plasma oxy-nitriding treatment on the surface of AISI 420 martensitic stainless steel. This treatment involved the sequential formation of nitride and oxide layers, to enhance surface hardness and corrosion resistance, respectively. The process resulted in the formation of a 20 μm-thick nitride layer and a 3 μm-thick oxide layer on the steel surface. Initially, the hardness increased by 2.2 times after nitriding, followed by a subsequent decrease of approximately 31 % after oxidation. While the nitriding process reduced corrosion resistance, the subsequent oxidation process led to the formation of a passive oxide film, effectively resolving this issue. The pitting corrosion of the oxide passive film started at 82.6 mVssc, providing better corrosion resistance characteristics than the nitride layer. Consequently, the trade-off between surface hardness and corrosion resistance in plasma oxy-nitrided AISI 420 martensitic stainless steel is anticipated to be recognized as an innovative and comprehensive surface treatment process for biomedical components.

1. 서 론
2. 실험방법
    2.1. AISI 420 시편
    2.2. 용체화 및 템퍼링 처리
    2.3. 플라즈마 산질화 처리
    2.4. 미세조직 및 결정구조 분석
    2.5. 경도 측정
    2.6. 동전위 분극 시험
3. 결과 및 고찰
    3.1. 플라즈마 산질화 처리 공정에 따른 미세조직의변화
    3.2. 플라즈마 산질화 처리 공정에 따른 상변태 거동
    3.3. 플라즈마 산질화 처리 공정에 따른 표면 경도
    3.4. 플라즈마 산질화 처리 공정에 따른 부식 특성변화
5. 결 론

• 김진한(전남대학교 공과대학 신소재공학부) | Jinhan Kim (School of Materials Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea)
• 이광민(전남대학교 공과대학 신소재공학부) | Kwangmin Lee (School of Materials Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea) Corresponding author