Pub Date : 2024-08-01DOI: 10.1007/s11085-024-10276-5
Irina Fedorova, Mikael Kjellen, Saud Saleem, Dennis Karlsson, Fredrik Meurling, Roger Berglund
Additions of titanium nitrides (TiN) can reduce cracking sensitivity of FeCrAl alloys manufactured by laser powder bed fusion through grain refinement. However, the oxidation behavior of TiN-added FeCrAl alloys is not reported up to date. In the present work, high-temperature oxidation of additively manufactured (AM) FeCrAl alloys with Ti additions from 0.5 to 1.1 w% has been studied in air at 1250 °C during 1000 h. The AM Ti-added FeCrAl alloys have shown a higher oxidation rate than their cast reference alloy. The degradation kinetics during high-temperature exposure of the model AM alloy are described and discussed with respect to the microstructural examination. The Ti addition is shown to affect the spallation kinetics. The formation of TiN precipitates at the metal/oxide interface and their growth within the alumina scale during the exposure at 1250 °C were revealed for the first time in FeCrAl material.
添加氮化钛(TiN)可通过细化晶粒降低激光粉末床熔融法制造的铁铬铝合金的开裂敏感性。然而,添加了 TiN 的 FeCrAl 合金的氧化行为迄今尚未见报道。在本研究中,研究了添加 0.5 至 1.1 w% Ti 的添加剂制造(AM)FeCrAl 合金在 1250 °C 空气中 1000 小时的高温氧化情况。AM 添加 Ti 的 FeCrAl 合金显示出比铸造参考合金更高的氧化率。描述了模型 AM 合金在高温暴露期间的降解动力学,并结合微观结构检查进行了讨论。结果表明,钛的添加会影响剥落动力学。在铁铬铝材料中首次发现了金属/氧化物界面上 TiN 沉淀的形成及其在 1250 °C 暴露期间在氧化铝鳞片内的生长。
{"title":"Oxidation Behavior of Additively Manufactured Ti-added FeCrAl Alloys","authors":"Irina Fedorova, Mikael Kjellen, Saud Saleem, Dennis Karlsson, Fredrik Meurling, Roger Berglund","doi":"10.1007/s11085-024-10276-5","DOIUrl":"10.1007/s11085-024-10276-5","url":null,"abstract":"<div><p>Additions of titanium nitrides (TiN) can reduce cracking sensitivity of FeCrAl alloys manufactured by laser powder bed fusion through grain refinement. However, the oxidation behavior of TiN-added FeCrAl alloys is not reported up to date. In the present work, high-temperature oxidation of additively manufactured (AM) FeCrAl alloys with Ti additions from 0.5 to 1.1 w% has been studied in air at 1250 °C during 1000 h. The AM Ti-added FeCrAl alloys have shown a higher oxidation rate than their cast reference alloy. The degradation kinetics during high-temperature exposure of the model AM alloy are described and discussed with respect to the microstructural examination. The Ti addition is shown to affect the spallation kinetics. The formation of TiN precipitates at the metal/oxide interface and their growth within the alumina scale during the exposure at 1250 °C were revealed for the first time in FeCrAl material.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"1155 - 1165"},"PeriodicalIF":2.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141887115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1007/s11085-024-10280-9
Bingtao Li, Lee M. Pike
High-temperature alloys rely on the formation of a protective oxide scale to resist high-temperature oxidation and corrosion attack, and chromia is the most common oxide to provide this function in commercial alloys. However, certain harsh environments require alloys that utilize the formation of even more protective oxide films to provide improved performance and longer lifetime. In these cases, an alumina scale becomes a viable solution to protect high-temperature alloys. This paper summarizes high-temperature oxidation and corrosion behaviors of several high-temperature Ni- and Co-base alloys tested under various high-temperature conditions, including short-term and long-term oxidation, cyclic oxidation, dynamic (burner rig) oxidation, water vapor oxidation, nitridation, and carburization at temperatures ranging from 871 to 1093 °C (1600–2000°F). The oxidation and corrosion behaviors are compared between the alumina-forming and chromia-forming alloys, and the results show that the alumina-forming alloys were significantly superior to the chromia-forming alloys for high-temperature oxidation and corrosion resistance in terms of oxidation and corrosion rate reduction, scale stability and adhesion, mass penetration suppression, etc. Based on the extensive tests, alumina scales were highly effective in resisting oxidation, nitridation, and carburization attacks, especially under severe oxidation and corrosion conditions. To further demonstrate the benefits of an alumina scale, an alumina-forming alloy with pre-oxidation heat-treatment was also studied in the nitridation test.
{"title":"Utilization of Alumina Scale Formation by Ni-Base Alloys for High-Temperature Oxidation and Corrosion Resistance in Harsh Environments","authors":"Bingtao Li, Lee M. Pike","doi":"10.1007/s11085-024-10280-9","DOIUrl":"10.1007/s11085-024-10280-9","url":null,"abstract":"<div><p>High-temperature alloys rely on the formation of a protective oxide scale to resist high-temperature oxidation and corrosion attack, and chromia is the most common oxide to provide this function in commercial alloys. However, certain harsh environments require alloys that utilize the formation of even more protective oxide films to provide improved performance and longer lifetime. In these cases, an alumina scale becomes a viable solution to protect high-temperature alloys. This paper summarizes high-temperature oxidation and corrosion behaviors of several high-temperature Ni- and Co-base alloys tested under various high-temperature conditions, including short-term and long-term oxidation, cyclic oxidation, dynamic (burner rig) oxidation, water vapor oxidation, nitridation, and carburization at temperatures ranging from 871 to 1093 °C (1600–2000°F). The oxidation and corrosion behaviors are compared between the alumina-forming and chromia-forming alloys, and the results show that the alumina-forming alloys were significantly superior to the chromia-forming alloys for high-temperature oxidation and corrosion resistance in terms of oxidation and corrosion rate reduction, scale stability and adhesion, mass penetration suppression, etc. Based on the extensive tests, alumina scales were highly effective in resisting oxidation, nitridation, and carburization attacks, especially under severe oxidation and corrosion conditions. To further demonstrate the benefits of an alumina scale, an alumina-forming alloy with pre-oxidation heat-treatment was also studied in the nitridation test.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 6","pages":"1315 - 1330"},"PeriodicalIF":2.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1007/s11085-024-10275-6
Kevin Gautier, Daniel Monceau, Enrica Epifano, Damien Connétable, Thomas Gheno
The role of nitrogen in the oxidation of Ti-2W, Ti-10Al-2W (at.%) and Ti6242S was investigated using experiments in air and in Ar-20%O2, and two-stage experiments where the reaction gas was switched from one mixture to the other. When switching from Ar-20%O2 to air, the oxidation rates first increased during a short period, then decreased. This surge of mass gain following the introduction of air was attributed to N pickup, forming a nitride layer and a N-enriched zone in the alloy, below the oxide layer. The subsequent decrease of oxidation rate was attributed to the formation of nitride and/or N-rich zone, which both act as diffusion barriers for oxygen. Switching from air to Ar-20%O2 caused an increase in the oxidation rate of the W-containing alloys, which was attributed to the consumption of this barrier. The gas change had no significant effect on the oxidation rate of Ti6242S, which formed a much thinner nitride layer in air. The faster the nitride layer grows, the faster it is consumed when removing N from the reaction gas, probably because of a higher diffusion rate of N in W-doped TiO2 compared to TiO2 formed on Ti6242S.
通过在空气和 Ar-20%O2 中的实验,以及将反应气体从一种混合物切换到另一种混合物的两阶段实验,研究了氮在 Ti-2W、Ti-10Al-2W (at.%) 和 Ti6242S 氧化过程中的作用。当从 Ar-20%O2 切换到空气时,氧化率首先在短时间内上升,然后下降。引入空气后质量增加的激增归因于 N 的拾取,在合金中氧化层以下形成了氮化物层和富含 N 的区域。随后氧化率的下降则归因于氮化物和/或 N 富集区的形成,它们都是氧气的扩散屏障。从空气切换到 Ar-20%O2 会导致含 W 合金的氧化速率增加,这归因于这种屏障的消耗。气体的变化对 Ti6242S 的氧化速率没有明显影响,Ti6242S 在空气中形成的氮化层要薄得多。氮化层的生长速度越快,从反应气体中去除 N 时氮化层的消耗速度也越快,这可能是因为与 Ti6242S 上形成的 TiO2 相比,掺 W 的 TiO2 中 N 的扩散速度更高。
{"title":"Study of the Role of Nitrogen in the Oxidation of Titanium-Based Alloys by Changing the Reaction Gas","authors":"Kevin Gautier, Daniel Monceau, Enrica Epifano, Damien Connétable, Thomas Gheno","doi":"10.1007/s11085-024-10275-6","DOIUrl":"10.1007/s11085-024-10275-6","url":null,"abstract":"<div><p>The role of nitrogen in the oxidation of Ti-2W, Ti-10Al-2W (at.%) and Ti6242S was investigated using experiments in air and in Ar-20%O<sub>2</sub>, and two-stage experiments where the reaction gas was switched from one mixture to the other. When switching from Ar-20%O<sub>2</sub> to air, the oxidation rates first increased during a short period, then decreased. This surge of mass gain following the introduction of air was attributed to N pickup, forming a nitride layer and a N-enriched zone in the alloy, below the oxide layer. The subsequent decrease of oxidation rate was attributed to the formation of nitride and/or N-rich zone, which both act as diffusion barriers for oxygen. Switching from air to Ar-20%O<sub>2</sub> caused an increase in the oxidation rate of the W-containing alloys, which was attributed to the consumption of this barrier. The gas change had no significant effect on the oxidation rate of Ti6242S, which formed a much thinner nitride layer in air. The faster the nitride layer grows, the faster it is consumed when removing N from the reaction gas, probably because of a higher diffusion rate of N in W-doped TiO<sub>2</sub> compared to TiO<sub>2</sub> formed on Ti6242S.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"861 - 872"},"PeriodicalIF":2.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10275-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1007/s11085-024-10256-9
S. Gray, M. Mphahlele, D. M. Collins, C. Jackson, M. C. Hardy, M. P. Taylor
Samples of the Ni-based superalloy, RR1000, were exposed to 98% Na2SO4/2% NaCl salts at 700 °C with a flux of 1.5 µg cm−2 h−1 in flowing air + 300 ppm SO2 for a total of 250 h. Three pre-exposure conditions were studied: a bare reference alloy; fast heating to the test temperature followed by a 100 h hold; heating at a rate of 5 °C min−1 to the test temperature following by a 100 h hold. The surface oxide formed under the latter two conditions were Cr2O3 or NiCr2O4, respectively. The results show corrosion pit formation on the surface of the base, reference sample, and no pits present on the sample with the preformed Cr2O3. Some protection was found for the sample heated at 5 °C min−1 with a delay in the progression to accelerated corrosion attack. Additional testing under moisture containing air was also conducted. This showed no obvious difference in surface oxide morphology under the two tested heating rates for the short-term exposures examined but a difference was noted to be dependent on the moisture content of the air.
{"title":"Comparison of Performance of NiCr2O4 and Cr2O3 Formed on the Ni-Based Superalloy RR1000 Under Corrosive Conditions","authors":"S. Gray, M. Mphahlele, D. M. Collins, C. Jackson, M. C. Hardy, M. P. Taylor","doi":"10.1007/s11085-024-10256-9","DOIUrl":"10.1007/s11085-024-10256-9","url":null,"abstract":"<div><p>Samples of the Ni-based superalloy, RR1000, were exposed to 98% Na<sub>2</sub>SO<sub>4</sub>/2% NaCl salts at 700 °C with a flux of 1.5 µg cm<sup>−2</sup> h<sup>−1</sup> in flowing air + 300 ppm SO<sub>2</sub> for a total of 250 h. Three pre-exposure conditions were studied: a bare reference alloy; fast heating to the test temperature followed by a 100 h hold; heating at a rate of 5 °C min<sup>−1</sup> to the test temperature following by a 100 h hold. The surface oxide formed under the latter two conditions were Cr<sub>2</sub>O<sub>3</sub> or NiCr<sub>2</sub>O<sub>4</sub>, respectively. The results show corrosion pit formation on the surface of the base, reference sample, and no pits present on the sample with the preformed Cr<sub>2</sub>O<sub>3</sub>. Some protection was found for the sample heated at 5 °C min<sup>−1</sup> with a delay in the progression to accelerated corrosion attack. Additional testing under moisture containing air was also conducted. This showed no obvious difference in surface oxide morphology under the two tested heating rates for the short-term exposures examined but a difference was noted to be dependent on the moisture content of the air.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"1091 - 1102"},"PeriodicalIF":2.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10256-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1007/s11085-024-10260-z
Sudhanva Madhusudan, Enrica Epifano, Jérôme Favergeon, Tom Sanviemvongsak, David Maréchal, Daniel Monceau
Intergranular oxidation (IGO) of the Ni-based superalloy Inconel 718 was studied at 650 °C, 700 °C and 900 °C. The oxidized samples were characterized by X-ray diffraction and scanning electron microscopy. For all the studied temperatures, the external scale was mainly composed of Cr2O3, while the oxides along the grain boundaries were rich in Al and, to a minor extent, Ti. This was consistent with thermodynamic computations. The time evolution of the maximum depth of IGO was found to be parabolic with an apparent activation energy of 164 kJ/mol. The results of this study confirm with three temperatures that IGO kinetics can be described using an extension of the Wagner’s theory of internal oxidation, as recently suggested in the literature at 850 °C. According to this description, the mechanisms controlling the IGO kinetics of Inconel 718 are the aluminum diffusion in the alloy matrix and the oxygen diffusion along the interface between the alloy matrix and the oxidized grain boundary.
{"title":"High Temperature Intergranular Oxidation of Nickel Based Superalloy Inconel 718","authors":"Sudhanva Madhusudan, Enrica Epifano, Jérôme Favergeon, Tom Sanviemvongsak, David Maréchal, Daniel Monceau","doi":"10.1007/s11085-024-10260-z","DOIUrl":"10.1007/s11085-024-10260-z","url":null,"abstract":"<div><p>Intergranular oxidation (IGO) of the Ni-based superalloy Inconel 718 was studied at 650 °C, 700 °C and 900 °C. The oxidized samples were characterized by <i>X</i>-ray diffraction and scanning electron microscopy. For all the studied temperatures, the external scale was mainly composed of Cr<sub>2</sub>O<sub>3</sub>, while the oxides along the grain boundaries were rich in Al and, to a minor extent, Ti. This was consistent with thermodynamic computations. The time evolution of the maximum depth of IGO was found to be parabolic with an apparent activation energy of 164 kJ/mol. The results of this study confirm with three temperatures that IGO kinetics can be described using an extension of the Wagner’s theory of internal oxidation, as recently suggested in the literature at 850 °C. According to this description, the mechanisms controlling the IGO kinetics of Inconel 718 are the aluminum diffusion in the alloy matrix and the oxygen diffusion along the interface between the alloy matrix and the oxidized grain boundary.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"873 - 884"},"PeriodicalIF":2.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10260-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.1007/s11085-024-10263-w
Anke S. Ulrich, Sergey Kasatikov, Till König, Andrea Fantin, Johannes T. Margraf, Mathias C. Galetz
Ni-Cu alloys are promising for application at temperatures between 400–900 °C and reducing atmospheres with high C-contents. Typically, under such conditions, metallic materials in contact with the C-rich atmosphere are degraded by a mechanism called metal dusting (MD). Ni-Cu-alloys do not form protective oxide scales, but their resistance is attributed to Cu, which catalytically inhibits the C-deposition on the surface. Adding other alloying elements, such as Mn or Fe, was found to enhance the MD attack of Ni-Cu alloys again. In this study, the effect of the Mn and Fe is divided into two affected areas: the surface and the bulk. The MD attack on binary Ni-Cu alloys, model alloys with Fe and Mn additions, and commercial Monel Alloy 400 is experimentally demonstrated. The surface electronic structure causing the adsorption and dissociation of C-containing molecules is investigated for model alloys. Analytical methods such as scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy, X-ray diffraction analysis, and near-edge X-ray absorption fine structure measurements were used. The results are correlated to CALPHAD calculations and atomistic simulations combining density functional theory calculations and machine learning. It is found that the Cu content plays a significant role in the surface reaction. The effect of Mn and Fe is mainly attributed to oxide formation. A mechanism explaining the enhanced attack by adding both Fe and Mn is proposed.
镍铜合金有望应用于温度介于 400-900 °C、高 C 含量的还原气氛中。通常情况下,在这种条件下,与富含 C 的气氛接触的金属材料会通过一种称为金属粉尘(MD)的机制发生降解。Ni-Cu 合金不会形成保护性氧化物鳞片,但其耐腐蚀性可归因于 Cu,Cu 可催化抑制 C 在表面的沉积。研究发现,添加其他合金元素(如 Mn 或 Fe)会再次增强 Ni-Cu 合金的 MD 攻击。在本研究中,Mn 和 Fe 的影响分为两个受影响区域:表面和主体。实验证明了对二元镍铜合金、添加了铁和锰的模型合金以及商用蒙乃尔合金 400 的 MD 攻击。针对模型合金,研究了导致含 C 分子吸附和解离的表面电子结构。分析方法包括扫描电子显微镜结合能量色散 X 射线光谱法、电子探针显微分析法结合波长色散 X 射线光谱法、X 射线衍射分析法和近边 X 射线吸收精细结构测量法。结果与 CALPHAD 计算以及结合密度泛函理论计算和机器学习的原子模拟相关联。研究发现,铜含量在表面反应中起着重要作用。锰和铁的影响主要归因于氧化物的形成。研究还提出了一种机制来解释添加铁和锰会增强侵蚀作用。
{"title":"Decreased Metal Dusting Resistance of Ni-Cu Alloys by Fe and Mn Additions","authors":"Anke S. Ulrich, Sergey Kasatikov, Till König, Andrea Fantin, Johannes T. Margraf, Mathias C. Galetz","doi":"10.1007/s11085-024-10263-w","DOIUrl":"10.1007/s11085-024-10263-w","url":null,"abstract":"<div><p>Ni-Cu alloys are promising for application at temperatures between 400–900 °C and reducing atmospheres with high C-contents. Typically, under such conditions, metallic materials in contact with the C-rich atmosphere are degraded by a mechanism called metal dusting (MD). Ni-Cu-alloys do not form protective oxide scales, but their resistance is attributed to Cu, which catalytically inhibits the C-deposition on the surface. Adding other alloying elements, such as Mn or Fe, was found to enhance the MD attack of Ni-Cu alloys again. In this study, the effect of the Mn and Fe is divided into two affected areas: the surface and the bulk. The MD attack on binary Ni-Cu alloys, model alloys with Fe and Mn additions, and commercial Monel Alloy 400 is experimentally demonstrated. The surface electronic structure causing the adsorption and dissociation of C-containing molecules is investigated for model alloys. Analytical methods such as scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy, X-ray diffraction analysis, and near-edge X-ray absorption fine structure measurements were used. The results are correlated to CALPHAD calculations and atomistic simulations combining density functional theory calculations and machine learning. It is found that the Cu content plays a significant role in the surface reaction. The effect of Mn and Fe is mainly attributed to oxide formation. A mechanism explaining the enhanced attack by adding both Fe and Mn is proposed.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 6","pages":"1301 - 1314"},"PeriodicalIF":2.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10263-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.1007/s11085-024-10269-4
T. Perez, S. Mathieu, L. Latu-Romain, Y. Wouters, M. Vilasi
A single thin MnCr2O4 spinel layer was synthesized on a Ni–25Cr–1.5Mn alloy by a fine control of oxygen partial pressure using the Rhines-pack method, a technique that utilized an appropriate buffering powder mixture. The spinel was characterized using X-Ray diffraction, Raman spectroscopy and photoelectrochemistry. The cubic spinel MnCr2O4 was formed under the oxygen partial pressure close to 5 × 10–21 atm at 1050 °C controlled by the buffering Ni–25Cr/Cr2O3 powder mixture. Raman MnCr2O4 spectrum is characterized by five vibrational modes, whereas photoelectrochemical characterization revealed the MnCr2O4 band gap measurement at 3.7 eV with an n-type conductivity.
{"title":"Growth of a Single MnCr2O4 Spinel on Ni–25Cr–1.5Mn Alloy by the Rhines Pack Method and Photoelectrochemical and Raman Signatures of MnCr2O4 Spinel","authors":"T. Perez, S. Mathieu, L. Latu-Romain, Y. Wouters, M. Vilasi","doi":"10.1007/s11085-024-10269-4","DOIUrl":"10.1007/s11085-024-10269-4","url":null,"abstract":"<div><p>A single thin MnCr<sub>2</sub>O<sub>4</sub> spinel layer was synthesized on a Ni–25Cr–1.5Mn alloy by a fine control of oxygen partial pressure using the Rhines-pack method, a technique that utilized an appropriate buffering powder mixture. The spinel was characterized using X-Ray diffraction, Raman spectroscopy and photoelectrochemistry. The cubic spinel MnCr<sub>2</sub>O<sub>4</sub> was formed under the oxygen partial pressure close to 5 × 10<sup>–21</sup> atm at 1050 °C controlled by the buffering Ni–25Cr/Cr<sub>2</sub>O<sub>3</sub> powder mixture. Raman MnCr<sub>2</sub>O<sub>4</sub> spectrum is characterized by five vibrational modes, whereas photoelectrochemical characterization revealed the MnCr<sub>2</sub>O<sub>4</sub> band gap measurement at 3.7 eV with an n-type conductivity.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"923 - 933"},"PeriodicalIF":2.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.1007/s11085-024-10287-2
Thuan Dinh Nguyen, Jianqiang Zhang, David J. Young
Model alloy, Fe-20Cr (wt%), was oxidized in two gas mixtures Ar-5H2O-(5H2) (vol%) at 850 °C. The alloy formed Cr2O3 scales in both gases. The Cr2O3 scale developed faster in Ar-5H2O-5H2 and contained fine pores, whilst that grown in Ar-5H2O was dense. Experiments with inert SiO2 marker revealed that the Cr2O3 scale growth in Ar-5H2O-(5H2) was controlled mainly by outward Cr diffusion. When adjusted for grain boundary diffusion effects, Wagner’s theory was successful in describing the hydrogen effect, provided that the Cr2O3 scales are n-type.
{"title":"Microstructure of Cr2O3 Scales Grown in Ar-5H2O-(5H2) at 850 °C","authors":"Thuan Dinh Nguyen, Jianqiang Zhang, David J. Young","doi":"10.1007/s11085-024-10287-2","DOIUrl":"10.1007/s11085-024-10287-2","url":null,"abstract":"<div><p>Model alloy, Fe-20Cr (wt%), was oxidized in two gas mixtures Ar-5H<sub>2</sub>O-(5H<sub>2</sub>) (vol%) at 850 °C. The alloy formed Cr<sub>2</sub>O<sub>3</sub> scales in both gases. The Cr<sub>2</sub>O<sub>3</sub> scale developed faster in Ar-5H<sub>2</sub>O-5H<sub>2</sub> and contained fine pores, whilst that grown in Ar-5H<sub>2</sub>O was dense. Experiments with inert SiO<sub>2</sub> marker revealed that the Cr<sub>2</sub>O<sub>3</sub> scale growth in Ar-5H<sub>2</sub>O-(5H<sub>2</sub>) was controlled mainly by outward Cr diffusion. When adjusted for grain boundary diffusion effects, Wagner’s theory was successful in describing the hydrogen effect, provided that the Cr<sub>2</sub>O<sub>3</sub> scales are <i>n</i>-type.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 6","pages":"1277 - 1286"},"PeriodicalIF":2.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10287-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-28DOI: 10.1007/s11085-024-10255-w
A. Martin, E. Drouelle, J. Rame, J. Cormier, F. Pedraza
Current nickel-based single crystal superalloys (SX) are mainly designed to increase significant mechanical loading at high temperatures. Therefore, the mechanical resistance is greatly dependant on the microstructure and on the potential metallurgical defects. Corrosion and oxidation at high temperatures may further induce a loss of load-bearing section and lower the overall mechanical performance of such single crystals. While the yet complex mechanical and corrosion mechanisms are relatively well established separately, little is known on their combined effects, let alone on as-cast (AC) versus fully heat-treated (FHT) microstructures. This paper shows that the low cycle fatigue (LCF) at 0.5 Hz, Rσ = 0.05 and 950 °C is lowered when the AM1 nickel-based single crystal superalloy is pre-corroded with 1 mg/cm2 Na2SO4 at 950 °C. The degradation increases with increasing pre-corrosion time due to the formation of a porous, brittle corrosion layer that favours the number of crack initiation sites, which are subsequently assisted by hot corrosion and oxidation. In addition, AM1 FHT shows better LCF fatigue resistance than AM1 AC, due to a better creep resistance of the FHT microstructure under these conditions.
{"title":"Low Cycle Fatigue/Corrosion Interactions at 950 °C of AM1 Single Crystal Nickel-Based Superalloy","authors":"A. Martin, E. Drouelle, J. Rame, J. Cormier, F. Pedraza","doi":"10.1007/s11085-024-10255-w","DOIUrl":"10.1007/s11085-024-10255-w","url":null,"abstract":"<div><p>Current nickel-based single crystal superalloys (SX) are mainly designed to increase significant mechanical loading at high temperatures. Therefore, the mechanical resistance is greatly dependant on the microstructure and on the potential metallurgical defects. Corrosion and oxidation at high temperatures may further induce a loss of load-bearing section and lower the overall mechanical performance of such single crystals. While the yet complex mechanical and corrosion mechanisms are relatively well established separately, little is known on their combined effects, let alone on as-cast (AC) versus fully heat-treated (FHT) microstructures. This paper shows that the low cycle fatigue (LCF) at 0.5 Hz, <i>R</i><sub><i>σ</i></sub> = 0.05 and 950 °C is lowered when the AM1 nickel-based single crystal superalloy is pre-corroded with 1 mg/cm<sup>2</sup> Na<sub>2</sub>SO<sub>4</sub> at 950 °C. The degradation increases with increasing pre-corrosion time due to the formation of a porous, brittle corrosion layer that favours the number of crack initiation sites, which are subsequently assisted by hot corrosion and oxidation. In addition, AM1 FHT shows better LCF fatigue resistance than AM1 AC, due to a better creep resistance of the FHT microstructure under these conditions.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"961 - 970"},"PeriodicalIF":2.1,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-27DOI: 10.1007/s11085-024-10261-y
Martin Batiste, Thomas Perez, Tom Sanviemvongsak, Clara Desgranges, Daniel Monceau
The isothermal oxidation of Ni-base single-crystal superalloy AM1 was investigated for up to 3600 h at 850 °C and 900 °C. The aim of the study was to test an existing model of oxidation kinetics that considers transitory oxide growth. The samples were characterized at various intervals to correlate the microstructure of the oxide scale with the oxidation kinetics. Transition alumina (θ) was observed among other transition oxides such as spinel, rutile, and chromia, which helped in understanding the nature and kinetics of the transitory stage. After a sufficiently long duration, all samples formed a continuous α-alumina layer at the metal/oxide interface. The previously published model, based on three kinetic parameters, was validated in the temperature range of 800–1200 °C. The duration of the transient regime characterized in this study at 850 °C and 900 °C was consistent with the kinetics model, with a slight increase in the value of the model parameter describing the lateral growth kinetics of α-alumina. This modification resulted in a slight reduction in the duration of the transient regime at low temperatures.
研究了镍基单晶超级合金 AM1 在 850 °C 和 900 °C 下长达 3600 小时的等温氧化过程。研究的目的是测试考虑了短暂氧化物生长的现有氧化动力学模型。在不同的时间间隔对样品进行了表征,以便将氧化鳞片的微观结构与氧化动力学联系起来。在尖晶石、金红石和铬铁矿等其他过渡氧化物中观察到了过渡氧化铝(θ),这有助于了解过渡阶段的性质和动力学。经过足够长的时间后,所有样品都在金属/氧化物界面形成了连续的 α 氧化铝层。之前公布的基于三个动力学参数的模型在 800-1200 °C 的温度范围内得到了验证。本研究描述的 850 ℃ 和 900 ℃ 下瞬态机制的持续时间与动力学模型一致,只是描述 α- 氧化铝横向生长动力学的模型参数值略有增加。这一修改导致低温下瞬态过程的持续时间略有缩短。
{"title":"Very Long Transient Oxidation of a Nickel-based Single-Crystal Superalloy at 900 °C and 850 °C","authors":"Martin Batiste, Thomas Perez, Tom Sanviemvongsak, Clara Desgranges, Daniel Monceau","doi":"10.1007/s11085-024-10261-y","DOIUrl":"10.1007/s11085-024-10261-y","url":null,"abstract":"<div><p>The isothermal oxidation of Ni-base single-crystal superalloy AM1 was investigated for up to 3600 h at 850 °C and 900 °C. The aim of the study was to test an existing model of oxidation kinetics that considers transitory oxide growth. The samples were characterized at various intervals to correlate the microstructure of the oxide scale with the oxidation kinetics. Transition alumina (<i>θ</i>) was observed among other transition oxides such as spinel, rutile, and chromia, which helped in understanding the nature and kinetics of the transitory stage. After a sufficiently long duration, all samples formed a continuous <i>α</i>-alumina layer at the metal/oxide interface. The previously published model, based on three kinetic parameters, was validated in the temperature range of 800–1200 °C. The duration of the transient regime characterized in this study at 850 °C and 900 °C was consistent with the kinetics model, with a slight increase in the value of the model parameter describing the lateral growth kinetics of <i>α</i>-alumina. This modification resulted in a slight reduction in the duration of the transient regime at low temperatures.</p></div>","PeriodicalId":724,"journal":{"name":"Oxidation of Metals","volume":"101 5","pages":"935 - 948"},"PeriodicalIF":2.1,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11085-024-10261-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}