Abstract This paper presents the experimental investigation of corrosion occurring at elevated te... more Abstract This paper presents the experimental investigation of corrosion occurring at elevated temperatures in various critical constructional components of husk-fired boiler. In order to reduce the impact of high operating temperatures on boiler components, some protection, in the form of high temperature resistant coating becomes necessary. The critical components of a boiler are generally made of stainless steel. In this work an attempt has been made to determine experimentally the corrosion resistance performance of 347H SS components coated with 75Ni25Cr. Specimens of 75Ni25Cr coated 347H SS and bare 347H SS were hung in an actual husk fired boiler near superheater region through soot blower dummy points. The temperature recorded by an industrial pyrometer near superheater region was about 750 ± 50 °C. These samples were hung for about 150 h in the above-mentioned environment and it was found that 75Ni25Cr coating offers substantial protection as the bare metal underwent severe corrosion.
Corrosion occurring at elevated temperatures is a serious problem in areas such as gas turbine ap... more Corrosion occurring at elevated temperatures is a serious problem in areas such as gas turbine applications and power plants that use high temperature boilers. In this paper, we carry out experimental investigation for reducing corrosion rate so as to enhance the corrosion and wear characteristics of 347HSS and quantify the effect of 75Ni25Cr on 347HSS in terms of improved corrosion resistance. A coating of 75Ni25Cr was deposited on 347HSS boiler tube by the process of Detonation Gun. Corrosion studies were conducted on bare as well as D-Gun coated 347H stainless steel specimens in air and simulated husk fired boiler atmosphere at 800°C under cyclic conditions. Each cycle consisted one hour of heating in the tubular furnace and 20 min of cooling at room temperature. Fifty such cycles were completed to observe performance of these specimens. The weight change measurements were performed after each cycle to establish the kinetics of corrosion using weighing balance. Scanning Electron ...
Fossil fuels like coal, oil and natural gas are continuously being used for electricity generatio... more Fossil fuels like coal, oil and natural gas are continuously being used for electricity generation. However, combustion of fossil fuels has raised environmental concerns which have forced the world to search for alternative sources of energy like geothermal, solar and biomass energy. Biomass is a carbon-based fuel, readily available in many parts of the world, highly volatile with less sulphur and nitrogen content, its ash possesses the property of absorbing carbon dioxide emissions, co-firing of biomass and coal increases thermal efficiency, it creates employment opportunities and provides a better way of utilization of agricultural waste. However, chlorine species from biomass combustion results in corrosion of boiler tubes at high temperature. In this review, challenges like fouling, agglomeration, gaseous emissions, emission of heavy metals, low heating value, storage and transportation problems and high temperature corrosion have been discussed, which can limit the flexibility,...
Corrosion in incinerators, power plants, and chemical industries are frequently encountered due t... more Corrosion in incinerators, power plants, and chemical industries are frequently encountered due to the presence of salts containing sodium, sulphur, and chlorine. To obviate this problem, bare and coated alloys were tested under environments simulating the conditions present inside incinerators and power plants. 0.2 wt.% zirconium powder was incorporated in the Cr 3 C 2 -(NiCr) coating powder. The original powder and Zr containing powder was sprayed on Superni 718 alloy by D-gun technique. The bare and coated alloys were tested under Na 2 SO 4 + K 2 SO 4 + NaCl + KCl and Na 2 SO 4 + NaCl environment. The corrosion rate of specimens was monitored using weight change measurements. Characterization of the corrosion products has been done using FE-SEM/EDS and XRD techniques. Bare and coated alloys showed very good corrosion resistance under given molten salt environments. Addition of 0.2wt.%Zr in Cr 3 C 2 -25%(NiCr) coating further greatly reduced the oxidation rate as well as improved the adherence of oxide scale to the coating surface during the time of corrosion.
Degradation by high temperature oxidation and hot corrosion is the main failure mode of component... more Degradation by high temperature oxidation and hot corrosion is the main failure mode of components in the hot section of gas turbines, boilers, industrial waste incinerators, metallurgical furnaces and petrochemical installations. Corrosive environment is because of the usage of wide range of fuel containing large amount of Cl and S together with the volatile alkali metals such as K and Na which leads to the degradation of material. To obviate this problem, superalloy Superco 605 has been studied in air as well as in molten salt environment at 900˚C for 100 cycles. Weight change measurements were taken by a digital electronic weighing balance having accuracy of 1 mg after each cycle (heating at 900°C for 1 hour. and subsequently cooling in air for 20 min.) which was used to determine the kinetics of corrosion. The oxide scales formed on the surface of the superalloy were characterized by various techniques such as FESEM, EDAX and XRD. It was found that superco 605 shows good oxidation resistance in air at 900°C but poor corrosion resistance in simulated incinerator environment.
Superalloys are widely used for high-temperature applications. But these alloys also suffered fro... more Superalloys are widely used for high-temperature applications. But these alloys also suffered from severe degradation where corrosion problem frequently encountered due to the presence of molten salt deposits. To obviate this problem, three nickel-and cobalt-based superalloys had been exposed to (Na 2 SO 4 -25%NaCl) at 900°C for 100 cycles. The resulting corrosion products were characterized using scanning electron microscopy and energy dispersive spectroscopy. It was observed that both Ni-based alloys exhibited improved corrosion resistance over the Co-based alloy in this aggressive environment. In Ni-based alloys, the scale contained oxides such as NiO, Cr 2 O 3 , Fe 2 O 3 , and spinel NiCr 2 O 4 , whereas in case of Co-based alloy, the scale contained CoO and CoNiO 2 .
Journal of Materials Engineering and Performance, 2014
Incinerators are being used to burn solid waste of all types. This burning of waste creates a ver... more Incinerators are being used to burn solid waste of all types. This burning of waste creates a very aggressive environment at extremely high temperature. This environment attacks the various components of the incinerators. Some studies have been reported regarding behavior of steels in simulated incinerator environment at 550°C. In present work superalloys Superco 605, Superni 600, and Superni 718 have been subjected to cyclic oxidation in 40 wt.% K 2 SO 4 + 40 wt.% Na 2 SO 4 + 10 wt.% KCl + 10 wt.% NaCl environment at 900°C under cyclic condition. Weight change measurements have been done and weight change has been plotted against the numbers of cycles. The oxide scales formed on the surface of the corroded superalloys have been characterize by FESEM, EDS, XRD, cross-sectional analysis, and x-ray mapping. The nickel-based superalloys Superni 600 and Superni 718 indicated better resistance to corrosion in the above environment whereas Superco 605 lead to massive weight gain.
Cr 3 C 2 -25(NiCr) and Cr 3 C 2 -25(NiCr)+0.4%CeO 2 coatings were deposited on nickel-based super... more Cr 3 C 2 -25(NiCr) and Cr 3 C 2 -25(NiCr)+0.4%CeO 2 coatings were deposited on nickel-based superalloy Superni 600 by Detonation-gun technique. Studies were conducted on bare and coated alloys in molten salt environment (Na 2 SO 4 -25%NaCl) at 900°C under cyclic condition. Characterization of the corrosion product was done using field emission scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction techniques. The bare Superni 600 shows penetration of corrosion beneath the metal layer thereby indicating internal oxidation. The coating of Cr 3 C 2 -25(NiCr) with 0.4%CeO 2 leads to the formation of adherent scale.
Cr 3 C 2 -NiCr coating has been widely used in the application of wear and corrosion resistance a... more Cr 3 C 2 -NiCr coating has been widely used in the application of wear and corrosion resistance at high temperature. Rare earth elements are generally added to enhance the corrosion resistance of coatings. In this study the oxidation behaviour of Cr 3 C 2 -NiCr coating was investigated at 900°C with & without the addition of CeO 2 by 0.4% by weight under cyclic conditions. Coating was sprayed on Superni 600 substrate by D-gun technique. Oxidation rate was determined by weight change/area vs. number of cycles plot. Scale formed on the surface of samples was examined using FESEM/EDAX, XRD, cross-sectional and X-ray mapping analysis. It was found that addition of CeO 2 in small amount has increased the oxidation resistance. The parabolic rate constant of Cr 3 C 2 -NiCr coated and Cr 3 C 2 -NiCr+0.4wt.%CeO 2 coated Superni 600 was found to be about 28 times and 60 times less than that of bare Superni 600.
Abstract This paper presents the experimental investigation of corrosion occurring at elevated te... more Abstract This paper presents the experimental investigation of corrosion occurring at elevated temperatures in various critical constructional components of husk-fired boiler. In order to reduce the impact of high operating temperatures on boiler components, some protection, in the form of high temperature resistant coating becomes necessary. The critical components of a boiler are generally made of stainless steel. In this work an attempt has been made to determine experimentally the corrosion resistance performance of 347H SS components coated with 75Ni25Cr. Specimens of 75Ni25Cr coated 347H SS and bare 347H SS were hung in an actual husk fired boiler near superheater region through soot blower dummy points. The temperature recorded by an industrial pyrometer near superheater region was about 750 ± 50 °C. These samples were hung for about 150 h in the above-mentioned environment and it was found that 75Ni25Cr coating offers substantial protection as the bare metal underwent severe corrosion.
Corrosion occurring at elevated temperatures is a serious problem in areas such as gas turbine ap... more Corrosion occurring at elevated temperatures is a serious problem in areas such as gas turbine applications and power plants that use high temperature boilers. In this paper, we carry out experimental investigation for reducing corrosion rate so as to enhance the corrosion and wear characteristics of 347HSS and quantify the effect of 75Ni25Cr on 347HSS in terms of improved corrosion resistance. A coating of 75Ni25Cr was deposited on 347HSS boiler tube by the process of Detonation Gun. Corrosion studies were conducted on bare as well as D-Gun coated 347H stainless steel specimens in air and simulated husk fired boiler atmosphere at 800°C under cyclic conditions. Each cycle consisted one hour of heating in the tubular furnace and 20 min of cooling at room temperature. Fifty such cycles were completed to observe performance of these specimens. The weight change measurements were performed after each cycle to establish the kinetics of corrosion using weighing balance. Scanning Electron ...
Fossil fuels like coal, oil and natural gas are continuously being used for electricity generatio... more Fossil fuels like coal, oil and natural gas are continuously being used for electricity generation. However, combustion of fossil fuels has raised environmental concerns which have forced the world to search for alternative sources of energy like geothermal, solar and biomass energy. Biomass is a carbon-based fuel, readily available in many parts of the world, highly volatile with less sulphur and nitrogen content, its ash possesses the property of absorbing carbon dioxide emissions, co-firing of biomass and coal increases thermal efficiency, it creates employment opportunities and provides a better way of utilization of agricultural waste. However, chlorine species from biomass combustion results in corrosion of boiler tubes at high temperature. In this review, challenges like fouling, agglomeration, gaseous emissions, emission of heavy metals, low heating value, storage and transportation problems and high temperature corrosion have been discussed, which can limit the flexibility,...
Corrosion in incinerators, power plants, and chemical industries are frequently encountered due t... more Corrosion in incinerators, power plants, and chemical industries are frequently encountered due to the presence of salts containing sodium, sulphur, and chlorine. To obviate this problem, bare and coated alloys were tested under environments simulating the conditions present inside incinerators and power plants. 0.2 wt.% zirconium powder was incorporated in the Cr 3 C 2 -(NiCr) coating powder. The original powder and Zr containing powder was sprayed on Superni 718 alloy by D-gun technique. The bare and coated alloys were tested under Na 2 SO 4 + K 2 SO 4 + NaCl + KCl and Na 2 SO 4 + NaCl environment. The corrosion rate of specimens was monitored using weight change measurements. Characterization of the corrosion products has been done using FE-SEM/EDS and XRD techniques. Bare and coated alloys showed very good corrosion resistance under given molten salt environments. Addition of 0.2wt.%Zr in Cr 3 C 2 -25%(NiCr) coating further greatly reduced the oxidation rate as well as improved the adherence of oxide scale to the coating surface during the time of corrosion.
Degradation by high temperature oxidation and hot corrosion is the main failure mode of component... more Degradation by high temperature oxidation and hot corrosion is the main failure mode of components in the hot section of gas turbines, boilers, industrial waste incinerators, metallurgical furnaces and petrochemical installations. Corrosive environment is because of the usage of wide range of fuel containing large amount of Cl and S together with the volatile alkali metals such as K and Na which leads to the degradation of material. To obviate this problem, superalloy Superco 605 has been studied in air as well as in molten salt environment at 900˚C for 100 cycles. Weight change measurements were taken by a digital electronic weighing balance having accuracy of 1 mg after each cycle (heating at 900°C for 1 hour. and subsequently cooling in air for 20 min.) which was used to determine the kinetics of corrosion. The oxide scales formed on the surface of the superalloy were characterized by various techniques such as FESEM, EDAX and XRD. It was found that superco 605 shows good oxidation resistance in air at 900°C but poor corrosion resistance in simulated incinerator environment.
Superalloys are widely used for high-temperature applications. But these alloys also suffered fro... more Superalloys are widely used for high-temperature applications. But these alloys also suffered from severe degradation where corrosion problem frequently encountered due to the presence of molten salt deposits. To obviate this problem, three nickel-and cobalt-based superalloys had been exposed to (Na 2 SO 4 -25%NaCl) at 900°C for 100 cycles. The resulting corrosion products were characterized using scanning electron microscopy and energy dispersive spectroscopy. It was observed that both Ni-based alloys exhibited improved corrosion resistance over the Co-based alloy in this aggressive environment. In Ni-based alloys, the scale contained oxides such as NiO, Cr 2 O 3 , Fe 2 O 3 , and spinel NiCr 2 O 4 , whereas in case of Co-based alloy, the scale contained CoO and CoNiO 2 .
Journal of Materials Engineering and Performance, 2014
Incinerators are being used to burn solid waste of all types. This burning of waste creates a ver... more Incinerators are being used to burn solid waste of all types. This burning of waste creates a very aggressive environment at extremely high temperature. This environment attacks the various components of the incinerators. Some studies have been reported regarding behavior of steels in simulated incinerator environment at 550°C. In present work superalloys Superco 605, Superni 600, and Superni 718 have been subjected to cyclic oxidation in 40 wt.% K 2 SO 4 + 40 wt.% Na 2 SO 4 + 10 wt.% KCl + 10 wt.% NaCl environment at 900°C under cyclic condition. Weight change measurements have been done and weight change has been plotted against the numbers of cycles. The oxide scales formed on the surface of the corroded superalloys have been characterize by FESEM, EDS, XRD, cross-sectional analysis, and x-ray mapping. The nickel-based superalloys Superni 600 and Superni 718 indicated better resistance to corrosion in the above environment whereas Superco 605 lead to massive weight gain.
Cr 3 C 2 -25(NiCr) and Cr 3 C 2 -25(NiCr)+0.4%CeO 2 coatings were deposited on nickel-based super... more Cr 3 C 2 -25(NiCr) and Cr 3 C 2 -25(NiCr)+0.4%CeO 2 coatings were deposited on nickel-based superalloy Superni 600 by Detonation-gun technique. Studies were conducted on bare and coated alloys in molten salt environment (Na 2 SO 4 -25%NaCl) at 900°C under cyclic condition. Characterization of the corrosion product was done using field emission scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction techniques. The bare Superni 600 shows penetration of corrosion beneath the metal layer thereby indicating internal oxidation. The coating of Cr 3 C 2 -25(NiCr) with 0.4%CeO 2 leads to the formation of adherent scale.
Cr 3 C 2 -NiCr coating has been widely used in the application of wear and corrosion resistance a... more Cr 3 C 2 -NiCr coating has been widely used in the application of wear and corrosion resistance at high temperature. Rare earth elements are generally added to enhance the corrosion resistance of coatings. In this study the oxidation behaviour of Cr 3 C 2 -NiCr coating was investigated at 900°C with & without the addition of CeO 2 by 0.4% by weight under cyclic conditions. Coating was sprayed on Superni 600 substrate by D-gun technique. Oxidation rate was determined by weight change/area vs. number of cycles plot. Scale formed on the surface of samples was examined using FESEM/EDAX, XRD, cross-sectional and X-ray mapping analysis. It was found that addition of CeO 2 in small amount has increased the oxidation resistance. The parabolic rate constant of Cr 3 C 2 -NiCr coated and Cr 3 C 2 -NiCr+0.4wt.%CeO 2 coated Superni 600 was found to be about 28 times and 60 times less than that of bare Superni 600.
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Papers by Deepa Mudgal