Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis
For rapid surface engineering of Cr-containing alloys by low-temperature nitrocarburization, we introduce a process based on pyrolysis of solid reagents, e.g., urea, performed in an evacuated closed vessel. Upon heating to temperatures high enough for rapid diffusion of interstitial solute, but low...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-11-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/11/11/1764 |
| _version_ | 1797509396575551488 |
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| author | Cyprian Illing Zhe Ren Anna Agaponova Arthur Heuer Frank Ernst |
| author_facet | Cyprian Illing Zhe Ren Anna Agaponova Arthur Heuer Frank Ernst |
| author_sort | Cyprian Illing |
| collection | DOAJ |
| description | For rapid surface engineering of Cr-containing alloys by low-temperature nitrocarburization, we introduce a process based on pyrolysis of solid reagents, e.g., urea, performed in an evacuated closed vessel. Upon heating to temperatures high enough for rapid diffusion of interstitial solute, but low enough to avoid second-phase precipitation, the reagent is pyrolyzed to a gas atmosphere containing molecules that (i) activate the alloy surface by stripping away the passivating Cr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula>O<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>-rich surface film (diffusion barrier) and (ii) rapidly infuse carbon and nitrogen into the alloy. We demonstrate quantitatively that this method can generate a subsurface zone with concentrated carbon and nitrogen comparable to what can be accomplished by established (e.g., gas-phase- or plasma-based) methods, but with significantly reduced processing time. As another important difference to established gas-phase processing, the interaction of gas molecules with the alloy surface can have auto-catalytic effects by altering the gas composition in a way that accelerates solute infusion by providing a high activity of HNCO. The new method lends itself to rapid experimentation with a minimum of laboratory equipment. |
| first_indexed | 2024-03-10T05:17:06Z |
| format | Article |
| id | doaj.art-c4fe61e3102242838383225892eaf962 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T05:17:06Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-c4fe61e3102242838383225892eaf9622023-11-23T00:23:13ZengMDPI AGMetals2075-47012021-11-011111176410.3390/met11111764Rapid Alloy Surface Engineering through Closed-Vessel Reagent PyrolysisCyprian Illing0Zhe Ren1Anna Agaponova2Arthur Heuer3Frank Ernst4Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USADepartment of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USADepartment of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USADepartment of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USADepartment of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USAFor rapid surface engineering of Cr-containing alloys by low-temperature nitrocarburization, we introduce a process based on pyrolysis of solid reagents, e.g., urea, performed in an evacuated closed vessel. Upon heating to temperatures high enough for rapid diffusion of interstitial solute, but low enough to avoid second-phase precipitation, the reagent is pyrolyzed to a gas atmosphere containing molecules that (i) activate the alloy surface by stripping away the passivating Cr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula>O<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>-rich surface film (diffusion barrier) and (ii) rapidly infuse carbon and nitrogen into the alloy. We demonstrate quantitatively that this method can generate a subsurface zone with concentrated carbon and nitrogen comparable to what can be accomplished by established (e.g., gas-phase- or plasma-based) methods, but with significantly reduced processing time. As another important difference to established gas-phase processing, the interaction of gas molecules with the alloy surface can have auto-catalytic effects by altering the gas composition in a way that accelerates solute infusion by providing a high activity of HNCO. The new method lends itself to rapid experimentation with a minimum of laboratory equipment.https://www.mdpi.com/2075-4701/11/11/1764alloy surface engineeringcolossal supersaturationnitrocarburizationreagent pyrolysisauto-catalytic effect |
| spellingShingle | Cyprian Illing Zhe Ren Anna Agaponova Arthur Heuer Frank Ernst Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis Metals alloy surface engineering colossal supersaturation nitrocarburization reagent pyrolysis auto-catalytic effect |
| title | Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis |
| title_full | Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis |
| title_fullStr | Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis |
| title_full_unstemmed | Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis |
| title_short | Rapid Alloy Surface Engineering through Closed-Vessel Reagent Pyrolysis |
| title_sort | rapid alloy surface engineering through closed vessel reagent pyrolysis |
| topic | alloy surface engineering colossal supersaturation nitrocarburization reagent pyrolysis auto-catalytic effect |
| url | https://www.mdpi.com/2075-4701/11/11/1764 |
| work_keys_str_mv | AT cyprianilling rapidalloysurfaceengineeringthroughclosedvesselreagentpyrolysis AT zheren rapidalloysurfaceengineeringthroughclosedvesselreagentpyrolysis AT annaagaponova rapidalloysurfaceengineeringthroughclosedvesselreagentpyrolysis AT arthurheuer rapidalloysurfaceengineeringthroughclosedvesselreagentpyrolysis AT frankernst rapidalloysurfaceengineeringthroughclosedvesselreagentpyrolysis |