Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel
Nanoflex stainless steel is a promising material for medical applications. However, improvement of its mechanical properties without compromising its corrosion resistance is still a challenge. In order to investigate the effect of the nitriding process on the corrosion and wear resistance of Sandvik...
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| Format: | Article |
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MDPI AG
2022-01-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/15/3/907 |
| _version_ | 1797486718326145024 |
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| author | Paweł Kochmański Marcin Długozima Jolanta Baranowska |
| author_facet | Paweł Kochmański Marcin Długozima Jolanta Baranowska |
| author_sort | Paweł Kochmański |
| collection | DOAJ |
| description | Nanoflex stainless steel is a promising material for medical applications. However, improvement of its mechanical properties without compromising its corrosion resistance is still a challenge. In order to investigate the effect of the nitriding process on the corrosion and wear resistance of Sandvik Nanoflex<sup>TM</sup> steel, a number of processes were carried out in a gas atmosphere with differing ammonia contents in the temperature range of 425–475 °C for 4 h. The mechanical properties and wear resistance of the layers were tested using the nanoindentation and pin-on-disc methods, respectively. In order to assess corrosion resistance, potentiodynamic tests were carried out in Ringer’s artificial body fluid and in a 3% aqueous solution of sodium chloride. The results are discussed herein with respect to the microstructural characteristics of the layers studied using light and scanning electron microscopy, X-ray diffraction phase analysis and wavelength dispersive X-ray microanalysis. The structure of nitrided layers included three zones: the subsurface zone composed of nitrides and the zones composed of metastable phases, i.e., the S phase (γN) and expanded martensite (αN) with possible precipitates of nitrides. The third zone adjacent to the steel core was enriched with carbon. The nitrided samples showed significant improvement in the wear rate while maintaining good corrosion resistance in comparison to the non-treated steel. We concluded that nitriding should be carried out at a temperature below 450 °C and in an atmosphere containing no more than approximately 50% ammonia in order to avoid nitrides precipitation. |
| first_indexed | 2024-03-09T23:37:17Z |
| format | Article |
| id | doaj.art-b4d7dcdfbed941a79b3e77292b7bf9c3 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T23:37:17Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-b4d7dcdfbed941a79b3e77292b7bf9c32023-11-23T16:59:06ZengMDPI AGMaterials1996-19442022-01-0115390710.3390/ma15030907Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless SteelPaweł Kochmański0Marcin Długozima1Jolanta Baranowska2Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology Szczecin, Al. Piastów 19, 70-310 Szczecin, PolandFaculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology Szczecin, Al. Piastów 19, 70-310 Szczecin, PolandFaculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology Szczecin, Al. Piastów 19, 70-310 Szczecin, PolandNanoflex stainless steel is a promising material for medical applications. However, improvement of its mechanical properties without compromising its corrosion resistance is still a challenge. In order to investigate the effect of the nitriding process on the corrosion and wear resistance of Sandvik Nanoflex<sup>TM</sup> steel, a number of processes were carried out in a gas atmosphere with differing ammonia contents in the temperature range of 425–475 °C for 4 h. The mechanical properties and wear resistance of the layers were tested using the nanoindentation and pin-on-disc methods, respectively. In order to assess corrosion resistance, potentiodynamic tests were carried out in Ringer’s artificial body fluid and in a 3% aqueous solution of sodium chloride. The results are discussed herein with respect to the microstructural characteristics of the layers studied using light and scanning electron microscopy, X-ray diffraction phase analysis and wavelength dispersive X-ray microanalysis. The structure of nitrided layers included three zones: the subsurface zone composed of nitrides and the zones composed of metastable phases, i.e., the S phase (γN) and expanded martensite (αN) with possible precipitates of nitrides. The third zone adjacent to the steel core was enriched with carbon. The nitrided samples showed significant improvement in the wear rate while maintaining good corrosion resistance in comparison to the non-treated steel. We concluded that nitriding should be carried out at a temperature below 450 °C and in an atmosphere containing no more than approximately 50% ammonia in order to avoid nitrides precipitation.https://www.mdpi.com/1996-1944/15/3/907low-temperature nitridinggas nitridingprecipitation-hardened stainless steelNanoflex steelS phaseexpanded austenite |
| spellingShingle | Paweł Kochmański Marcin Długozima Jolanta Baranowska Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel Materials low-temperature nitriding gas nitriding precipitation-hardened stainless steel Nanoflex steel S phase expanded austenite |
| title | Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel |
| title_full | Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel |
| title_fullStr | Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel |
| title_full_unstemmed | Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel |
| title_short | Structure and Properties of Gas-Nitrided, Precipitation-Hardened Martensitic Stainless Steel |
| title_sort | structure and properties of gas nitrided precipitation hardened martensitic stainless steel |
| topic | low-temperature nitriding gas nitriding precipitation-hardened stainless steel Nanoflex steel S phase expanded austenite |
| url | https://www.mdpi.com/1996-1944/15/3/907 |
| work_keys_str_mv | AT pawełkochmanski structureandpropertiesofgasnitridedprecipitationhardenedmartensiticstainlesssteel AT marcindługozima structureandpropertiesofgasnitridedprecipitationhardenedmartensiticstainlesssteel AT jolantabaranowska structureandpropertiesofgasnitridedprecipitationhardenedmartensiticstainlesssteel |