Pub Date : 2023-02-22DOI: 10.1080/09603409.2023.2175563
Adam Wojcik, Matthew Waitt, Alberto S. Santos, A. Shibli
ABSTRACT To help determine remaining lifetime of pressure vessels suffering creep, the authors have previously developed a method and presented promising results using a combination of AC and DC electrical potential drop (EPD) on-line monitoring, detecting both final cracking as well as incipient creep damage. The latter was tentatively ascribed to the development of cavitation damage, but recent modelling and separate off-line measurements have shown that cavitation is unlikely to provide enough of a change in electrical properties to explain all of the variations previously observed. Here we gather the results obtained to date, and review their likely relationships in an attempt to obtain a greater insight into the mechanisms at play. Whilst changes in both on-line and off-line EPD are largely in accord, the belief now is that the changes seen cannot be fully explained by cavitation development and that EPD is responding to other creep induced phenomena as well.
{"title":"A review of factors affecting the use of Electrical Potential Drop (EPD) for creep life monitoring","authors":"Adam Wojcik, Matthew Waitt, Alberto S. Santos, A. Shibli","doi":"10.1080/09603409.2023.2175563","DOIUrl":"https://doi.org/10.1080/09603409.2023.2175563","url":null,"abstract":"ABSTRACT To help determine remaining lifetime of pressure vessels suffering creep, the authors have previously developed a method and presented promising results using a combination of AC and DC electrical potential drop (EPD) on-line monitoring, detecting both final cracking as well as incipient creep damage. The latter was tentatively ascribed to the development of cavitation damage, but recent modelling and separate off-line measurements have shown that cavitation is unlikely to provide enough of a change in electrical properties to explain all of the variations previously observed. Here we gather the results obtained to date, and review their likely relationships in an attempt to obtain a greater insight into the mechanisms at play. Whilst changes in both on-line and off-line EPD are largely in accord, the belief now is that the changes seen cannot be fully explained by cavitation development and that EPD is responding to other creep induced phenomena as well.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"89 1","pages":"148 - 164"},"PeriodicalIF":1.3,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80234102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-22DOI: 10.1080/09603409.2023.2181569
I. Nonaka
ABSTRACT In Japan, national guidelines of residual life evaluation for aged thermal power equipment were formulated in 1999. Several issues had recently come to light with the increase in ageing systems, including the emergence of unexpected mode of creep damage, the verification of practical applicability of the damage calibration curve generated in the laboratory, how to deal with creep-fatigue damage due to increased numbers of plant starts and stops, occurrence of plastic deformation in the accelerated creep test and the need for the creep damage monitoring method during plant operation. The Working Group to Advance Residual Life Evaluation Techniques was established in 2011 within the Society of Materials Science, Japan, to identify issues and discuss improvement measures. This paper provides an overview of the results of the working group activities.
{"title":"Activities to advance residual life evaluation techniques for highly aged power boiler materials","authors":"I. Nonaka","doi":"10.1080/09603409.2023.2181569","DOIUrl":"https://doi.org/10.1080/09603409.2023.2181569","url":null,"abstract":"ABSTRACT In Japan, national guidelines of residual life evaluation for aged thermal power equipment were formulated in 1999. Several issues had recently come to light with the increase in ageing systems, including the emergence of unexpected mode of creep damage, the verification of practical applicability of the damage calibration curve generated in the laboratory, how to deal with creep-fatigue damage due to increased numbers of plant starts and stops, occurrence of plastic deformation in the accelerated creep test and the need for the creep damage monitoring method during plant operation. The Working Group to Advance Residual Life Evaluation Techniques was established in 2011 within the Society of Materials Science, Japan, to identify issues and discuss improvement measures. This paper provides an overview of the results of the working group activities.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"1 1","pages":"134 - 141"},"PeriodicalIF":1.3,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78933867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-22DOI: 10.1080/09603409.2023.2175154
P. Decoussemaeker, S. Vittal, Shayan I Ahmed
ABSTRACT To ensure a good return on investment, it is important for power plant operators to set up an asset management program that will ensure reliable operation over the commercial life of the plant. General Electric (GE) has been applying a variety of asset management technologies to improve power plant life and performance for our customers. These methods consider various inputs including equipment design knowledge; asset condition assessed from real-time monitoring and inspection data; and lessons learned from repairing, operating and maintaining thousands of assets globally. In this paper, a subset of that information is applied to develop a methodology to perform risk-based health and life assessments for steam turbines and generators. The method has been used on several steam power plants around the world, to help operators of ageing steam plants make the right decisions related to end-of-life management or life extension.
{"title":"Risk-based asset life management for steam turbines and generators","authors":"P. Decoussemaeker, S. Vittal, Shayan I Ahmed","doi":"10.1080/09603409.2023.2175154","DOIUrl":"https://doi.org/10.1080/09603409.2023.2175154","url":null,"abstract":"ABSTRACT To ensure a good return on investment, it is important for power plant operators to set up an asset management program that will ensure reliable operation over the commercial life of the plant. General Electric (GE) has been applying a variety of asset management technologies to improve power plant life and performance for our customers. These methods consider various inputs including equipment design knowledge; asset condition assessed from real-time monitoring and inspection data; and lessons learned from repairing, operating and maintaining thousands of assets globally. In this paper, a subset of that information is applied to develop a methodology to perform risk-based health and life assessments for steam turbines and generators. The method has been used on several steam power plants around the world, to help operators of ageing steam plants make the right decisions related to end-of-life management or life extension.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"109 1","pages":"142 - 147"},"PeriodicalIF":1.3,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84894104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-21DOI: 10.1080/09603409.2023.2175562
F. Abe
ABSTRACT The role of BN, AlN and MnS particles on the degradation in creep life and rupture ductility has been investigated for 9 to 12Cr martensitic steels and 1Cr bainitic steel mainly at 550 to 650 oC. The BN particles form in Gr.92 and Gr.122 during normalising at around 1100 oC. The BN particles have nothing to do with the degradation in creep life. The AlN particles precipitate in the high-Al heats of 12Cr-1Mo-1 W-0.3 V steel during creep, reducing dissolved nitrogen and fine nitrides beneficial for the creep strength and degrading the creep life. The MnS particles have nothing to do with the degradation in creep life of 1Cr-1Mo-0.25 V steel. The BN, AlN and MnS particles are responsible for the degradation in reduction of area of the steels by accelerating the formation of creep voids at interfaces between the particles and alloy matrix.
{"title":"Role of inclusions on degradation in creep life and rupture ductility of ferritic power plant steels","authors":"F. Abe","doi":"10.1080/09603409.2023.2175562","DOIUrl":"https://doi.org/10.1080/09603409.2023.2175562","url":null,"abstract":"ABSTRACT The role of BN, AlN and MnS particles on the degradation in creep life and rupture ductility has been investigated for 9 to 12Cr martensitic steels and 1Cr bainitic steel mainly at 550 to 650 oC. The BN particles form in Gr.92 and Gr.122 during normalising at around 1100 oC. The BN particles have nothing to do with the degradation in creep life. The AlN particles precipitate in the high-Al heats of 12Cr-1Mo-1 W-0.3 V steel during creep, reducing dissolved nitrogen and fine nitrides beneficial for the creep strength and degrading the creep life. The MnS particles have nothing to do with the degradation in creep life of 1Cr-1Mo-0.25 V steel. The BN, AlN and MnS particles are responsible for the degradation in reduction of area of the steels by accelerating the formation of creep voids at interfaces between the particles and alloy matrix.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"41 1","pages":"110 - 124"},"PeriodicalIF":1.3,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72528482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-21DOI: 10.1080/09603409.2023.2177939
Caixia Xia, Xiangyu Liu, Zaiwang Huang
ABSTRACT Isothermal oxidation behaviour of two nickel base superalloys with different Cr contents was investigated in the temperature range of 700–800 °C. Weight–change curves show that weight loss increases with increasing temperature and a relatively lower Cr ratio corresponds to slow weight gain rate. Microscopic observations uncover that oxidation penetration attacks the alloys primarily along grain boundary especially for the lower-Cr alloy, and the penetration depth is strongly dependent on the oxidation temperature. The underlying oxidation mechanisms of the two alloys are explained using energy-dispersive x-ray spectroscopy and X-ray photoelectron spectroscopy.
{"title":"Effect of Cr on the oxidation behaviour of polycrystalline nickel based superalloys","authors":"Caixia Xia, Xiangyu Liu, Zaiwang Huang","doi":"10.1080/09603409.2023.2177939","DOIUrl":"https://doi.org/10.1080/09603409.2023.2177939","url":null,"abstract":"ABSTRACT Isothermal oxidation behaviour of two nickel base superalloys with different Cr contents was investigated in the temperature range of 700–800 °C. Weight–change curves show that weight loss increases with increasing temperature and a relatively lower Cr ratio corresponds to slow weight gain rate. Microscopic observations uncover that oxidation penetration attacks the alloys primarily along grain boundary especially for the lower-Cr alloy, and the penetration depth is strongly dependent on the oxidation temperature. The underlying oxidation mechanisms of the two alloys are explained using energy-dispersive x-ray spectroscopy and X-ray photoelectron spectroscopy.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"4 1","pages":"185 - 191"},"PeriodicalIF":1.3,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76831103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-07DOI: 10.1080/09603409.2023.2175293
Patric de Smet, Koon-ging Tang, Michael Bok
ABSTRACT A test manifold of grade P93 is welded under shop fabrication conditions. Raw materials include pipe and forgings. Welding processes used are GTAW and SMAW. Weld joints involve heavy wall butt welds and branch joints. Welded joints are subjected to different heat treatment cycles to assess the effect on the materials’ properties. Welding experiences and mechanical test results in relation to PWHT and ageing are discussed. Tensile test results comply with the requirements. Achieving impact toughness requirements appears to be challenging, however improvements are expected through further optimisation of heat treatment and welding procedures.
{"title":"Experience of P93 manifold welding under fabrication conditions","authors":"Patric de Smet, Koon-ging Tang, Michael Bok","doi":"10.1080/09603409.2023.2175293","DOIUrl":"https://doi.org/10.1080/09603409.2023.2175293","url":null,"abstract":"ABSTRACT A test manifold of grade P93 is welded under shop fabrication conditions. Raw materials include pipe and forgings. Welding processes used are GTAW and SMAW. Weld joints involve heavy wall butt welds and branch joints. Welded joints are subjected to different heat treatment cycles to assess the effect on the materials’ properties. Welding experiences and mechanical test results in relation to PWHT and ageing are discussed. Tensile test results comply with the requirements. Achieving impact toughness requirements appears to be challenging, however improvements are expected through further optimisation of heat treatment and welding procedures.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"15 1","pages":"125 - 133"},"PeriodicalIF":1.3,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81453129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-06DOI: 10.1080/09603409.2023.2173717
S. Holdsworth
ABSTRACT In recent years, there has increasingly been the requirement for turbine generators to operate more efficiently, and in a more flexible way. Traditionally, the effectiveness of assessment procedures used to predict component integrity has been established on the basis of service experience. As the demand has increased for new materials to be adopted after increasingly shorter development periods, and more efficient and flexible operation to complement the availability of renewable energies has become the norm, it has no longer been possible to evaluate assessment effectiveness on the basis of prior operating experience, since it did not exist. The solution has been to use the results of component-feature specimen tests. Initially, these were full section isothermal benchmark tests conducted at the maximum operating temperature. Now the verification of assessment effectiveness using component-feature specimen, service-cycle TMF testing has become more realistic and economically viable, with (i) component-feature specimens of a more conventional laboratory testing size, but meeting prior defined geometry and damage mechanism requirements, and (ii) service-cycle details based on the results of operation-based non-linear (elastic-plastic-creep) finite element analysis.
{"title":"High temperature component integrity in turbines required for flexible operation – evaluating assessment effectiveness","authors":"S. Holdsworth","doi":"10.1080/09603409.2023.2173717","DOIUrl":"https://doi.org/10.1080/09603409.2023.2173717","url":null,"abstract":"ABSTRACT In recent years, there has increasingly been the requirement for turbine generators to operate more efficiently, and in a more flexible way. Traditionally, the effectiveness of assessment procedures used to predict component integrity has been established on the basis of service experience. As the demand has increased for new materials to be adopted after increasingly shorter development periods, and more efficient and flexible operation to complement the availability of renewable energies has become the norm, it has no longer been possible to evaluate assessment effectiveness on the basis of prior operating experience, since it did not exist. The solution has been to use the results of component-feature specimen tests. Initially, these were full section isothermal benchmark tests conducted at the maximum operating temperature. Now the verification of assessment effectiveness using component-feature specimen, service-cycle TMF testing has become more realistic and economically viable, with (i) component-feature specimens of a more conventional laboratory testing size, but meeting prior defined geometry and damage mechanism requirements, and (ii) service-cycle details based on the results of operation-based non-linear (elastic-plastic-creep) finite element analysis.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"31 1","pages":"165 - 173"},"PeriodicalIF":1.3,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86015975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-01-02DOI: 10.1080/09603409.2022.2160896
M. Banaszkiewicz, J. Badur
ABSTRACT The paper presents a critical analysis of the procedures for defect propagation assessment recommended by British standards and their application to rotating components. The way of applying these procedures was shown by an example of a steam turbine rotor with particular use of a characteristic strain model of high-temperature creep. Calculations of the flaws located at the rotor axis have shown that their growth in the design life is small. The performed analyses have also shown that crack development due to low-cycle fatigue is comparable to that due to creep and cannot be ignored under typical service condition. It was also shown that there is no risk of brittle fracture in the rotor under typical start-up conditions. The presented results prove the usefulness of the methods included in the British standards and guidelines for crack growth assessment in components subject to centrifugal load.
{"title":"Creep-fatigue defect development and risk of brittle fracture in the ultrasupercritical steam turbine rotors","authors":"M. Banaszkiewicz, J. Badur","doi":"10.1080/09603409.2022.2160896","DOIUrl":"https://doi.org/10.1080/09603409.2022.2160896","url":null,"abstract":"ABSTRACT The paper presents a critical analysis of the procedures for defect propagation assessment recommended by British standards and their application to rotating components. The way of applying these procedures was shown by an example of a steam turbine rotor with particular use of a characteristic strain model of high-temperature creep. Calculations of the flaws located at the rotor axis have shown that their growth in the design life is small. The performed analyses have also shown that crack development due to low-cycle fatigue is comparable to that due to creep and cannot be ignored under typical service condition. It was also shown that there is no risk of brittle fracture in the rotor under typical start-up conditions. The presented results prove the usefulness of the methods included in the British standards and guidelines for crack growth assessment in components subject to centrifugal load.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"367 1","pages":"1 - 12"},"PeriodicalIF":1.3,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82582353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-01-02DOI: 10.1080/09603409.2022.2162684
A. Bajwoluk, P. Gutowski
ABSTRACT During the carburising processes, treated elements are transported on a specially designed technological equipment of the furnaces. This equipment works in particularly hard conditions. This is because in each work cycle, apart from the load carried by the charge, it is subjected to harmful effect of many other factors such as the highly carburising technical atmosphere of the furnace and high and rapidly changing temperature. These factors influence fatigue changes in the equipment’s parts, the observable effect of which may be cracks on the surface, propagating deeper into the material in subsequent cycles. A pivotal factor influencing the kinetics of fatigue processes in the carburising furnaces equipment are thermal stresses appearing in each operating cycle, with each temperature change. The thermal stresses in this equipment are caused by the temperature gradient across the section of the heated or cooled element and different thermal expansion of the structural components of the carburised alloy. In the paper, on the developed FEM model of the subsurface layer of a carburised rib of a pallet for transporting the charge in the furnace, analyses of stress distributions during rapid cooling were carried out. These analyses were performed with taking into account the separate impact of the above-mentioned sources of thermal stresses and their simultaneous action. In the analyses which consider the influence of the temperature gradient, the main load factor was the temperature distribution determined on the basis of the heat flow analyses carried out for the analysed section of pallets rib. The conducted analyses made it possible to assess the impact of local stresses caused by different thermal expansion of structural components of the carburised alloy on the change in the distribution of global stresses caused by the temperature gradient formed during rapid cooling. Based on the obtained results, it was assessed how the increased concentration of carbide precipitates, characteristic for the grain boundary of the carburised alloy, favours the formation of cracks observed in real castings, and whether the analysed stress sources have a significant impact on the kinetics of fatigue processes.
{"title":"Analysis of thermal stresses synergy in surface layer of carburised creep-resistant casts during rapid cooling processes","authors":"A. Bajwoluk, P. Gutowski","doi":"10.1080/09603409.2022.2162684","DOIUrl":"https://doi.org/10.1080/09603409.2022.2162684","url":null,"abstract":"ABSTRACT During the carburising processes, treated elements are transported on a specially designed technological equipment of the furnaces. This equipment works in particularly hard conditions. This is because in each work cycle, apart from the load carried by the charge, it is subjected to harmful effect of many other factors such as the highly carburising technical atmosphere of the furnace and high and rapidly changing temperature. These factors influence fatigue changes in the equipment’s parts, the observable effect of which may be cracks on the surface, propagating deeper into the material in subsequent cycles. A pivotal factor influencing the kinetics of fatigue processes in the carburising furnaces equipment are thermal stresses appearing in each operating cycle, with each temperature change. The thermal stresses in this equipment are caused by the temperature gradient across the section of the heated or cooled element and different thermal expansion of the structural components of the carburised alloy. In the paper, on the developed FEM model of the subsurface layer of a carburised rib of a pallet for transporting the charge in the furnace, analyses of stress distributions during rapid cooling were carried out. These analyses were performed with taking into account the separate impact of the above-mentioned sources of thermal stresses and their simultaneous action. In the analyses which consider the influence of the temperature gradient, the main load factor was the temperature distribution determined on the basis of the heat flow analyses carried out for the analysed section of pallets rib. The conducted analyses made it possible to assess the impact of local stresses caused by different thermal expansion of structural components of the carburised alloy on the change in the distribution of global stresses caused by the temperature gradient formed during rapid cooling. Based on the obtained results, it was assessed how the increased concentration of carbide precipitates, characteristic for the grain boundary of the carburised alloy, favours the formation of cracks observed in real castings, and whether the analysed stress sources have a significant impact on the kinetics of fatigue processes.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"39 1","pages":"64 - 76"},"PeriodicalIF":1.3,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79401150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-01-02DOI: 10.1080/09603409.2023.2171546
Gitanjaly Goyal, N. Bala, H. Singh, S. Prakash
ABSTRACT High temperature corrosion of metals and alloys can be controlled by the use of inhibitors and fuel additives. In this work three different types of coatings namely Y2O3, SnO2 and ZrO2 coatings were superficially applied on Ni base superalloy Superni 718. Accelerated corrosion testing of the uncoated as well as the coated superalloy was done in a molten salt environment (Na2SO4-60%V2O5) at 900°C for 50 cycles. Each cycle consisted of 1 hour heating in a Silicon Carbide Tube furnace followed by 20 minutes cooling in ambient air. Weight change measurements after each cycle were taken by an electronic balance having an accuracy of 0.01 mg. XRD, SEM and EPMA analyses of the exposed specimens were carried out to characterise the oxide scales. The bare superalloy showed more overall weight gain, in comparison with all the coated counterparts. It was concluded that ZrO2 was most effective in reducing corrosion rate in alloy A.
{"title":"Comparative study of Y2O3, SnO2 and ZrO2 as inhibitor to control high temperature corrosion of Ni-based superalloy","authors":"Gitanjaly Goyal, N. Bala, H. Singh, S. Prakash","doi":"10.1080/09603409.2023.2171546","DOIUrl":"https://doi.org/10.1080/09603409.2023.2171546","url":null,"abstract":"ABSTRACT High temperature corrosion of metals and alloys can be controlled by the use of inhibitors and fuel additives. In this work three different types of coatings namely Y2O3, SnO2 and ZrO2 coatings were superficially applied on Ni base superalloy Superni 718. Accelerated corrosion testing of the uncoated as well as the coated superalloy was done in a molten salt environment (Na2SO4-60%V2O5) at 900°C for 50 cycles. Each cycle consisted of 1 hour heating in a Silicon Carbide Tube furnace followed by 20 minutes cooling in ambient air. Weight change measurements after each cycle were taken by an electronic balance having an accuracy of 0.01 mg. XRD, SEM and EPMA analyses of the exposed specimens were carried out to characterise the oxide scales. The bare superalloy showed more overall weight gain, in comparison with all the coated counterparts. It was concluded that ZrO2 was most effective in reducing corrosion rate in alloy A.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":"5 1","pages":"13 - 23"},"PeriodicalIF":1.3,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85266939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：