The Experts below are selected from a list of 1245 Experts worldwide ranked by ideXlab platform
Tapas Laha - One of the best experts on this subject based on the ideXlab platform.
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Multi-scale mechanical properties of Fe-based amorphous/Nanocrystalline Composite coating synthesized by HVOF spraying
Journal of Alloys and Compounds, 2020Co-Authors: Sapan K. Nayak, Abhishek Pathak, Atanu Banerjee, Anil Kumar, Tapas LahaAbstract:Abstract Fe-based (Fe–Cr–B–P–C) amorphous/Nanocrystalline Composite coatings were synthesized by high velocity oxy-fuel (HVOF) thermal spray method with varying powder feed rates and the multi-scale wear behaviour of the coatings' is reported here. Microstructural characterization of the Composite coating envisaged the presence of embedded Nanocrystalline phases in the amorphous matrix. The porosity content decreased, whereas the amorphicity of the coating increased gradually with increment in the feed rate. The combined effect of (i) splat morphology and (ii) extent of devitrification on the mechanical and tribological properties of the various coatings was investigated. Increasing the powder feed rate resulted in higher hardness of the coating, which was attributed to better inter-splat bonding and reduction in α-Fe content in the amorphous matrix of the coating due to lower extent of devitrification. Nanotribology test on a single-splat revealed increment in wear resistance at elevated feed rate due to the reduction in volume fraction of softer Nanocrystalline α-Fe phases. Besides, dry sliding wear investigated the coating's wear behaviour on a global basis and revealed decreasing trends for both wear rate and coefficient of friction with increasing feed rate. Most importantly, the Fe-based Composite coatings exhibited low wear volume during nanotribology and lower friction coefficient, low wear rate of dry sliding wear study, compared to an SS316L coating, prepared using industrially optimized parameters. The enhanced wear resistance of the Composite coating compared to that of the stainless steel coating makes it an effective method of surface protection for metallic substrates.
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A Study on the Corrosion Inhibition of Fe-Based Amorphous/Nanocrystalline Coating Synthesized by High-Velocity Oxy-Fuel Spraying in an Extreme Environment
Journal of Thermal Spray Technology, 2019Co-Authors: Sapan K. Nayak, Kuntal Sarkar, Abhishek Pathak, Atanu Banerjee, Anil Kumar, Tapas LahaAbstract:In this work, Fe-based (Fe-Cr-B-P-C) amorphous/Nanocrystalline Composite coatings were deposited by high-velocity oxy-fuel thermal spray method with varying powder feed rates and their behavior in saline environment was investigated. An SS316L coating with optimized parameters was also prepared for comparison purpose. The microstructural characterization of the Composite coatings revealed the presence of embedded Nanocrystalline phases in the amorphous matrix. The amorphicity of the coating increased, whereas the porosity content decreased gradually with the increment in feed rate during the spraying process. The combined effect of extent of devitrification and porosity content on the corrosion behavior of the various coatings was analyzed. Potentiodynamic polarization and electrochemical impedance spectroscopy studies revealed that the Fe-based Composite coatings exhibited significantly lower corrosion current density and higher polarization resistance than that of the mild steel substrate as well as SS316L coating. The enhanced corrosion resistance of the Composite coatings is ascribed to the combined effect of lower porosity content and retained amorphous phase. In addition, the formation of chromium hydroxide along with some of the oxides and hydroxides of iron in the post-corroded coating samples aids in impeding the corrosive solution penetration, thereby increasing the corrosion inhibition efficiency of the Composite coatings.Graphic Abstract
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Optimization of mechanical and corrosion properties of plasma sprayed low-chromium containing Fe-based amorphous/Nanocrystalline Composite coating
Surface & Coatings Technology, 2019Co-Authors: Anil Kumar, Sapan K. Nayak, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Tapas LahaAbstract:Abstract In this work, iron (Fe)-based amorphous/Nanocrystalline Composite coatings were synthesized using low-chromium containing amorphous powder (Fe73Cr2Si11B11C3, at. %) via atmospheric plasma spraying (APS) at different plasma spraying parameters. Coatings were deposited with 2 and 3 numbers of torch pass to get different coating thickness, along with the plasma power range was varied from 25 kW to 35 kW to alter the degree of powder melting. Microstructural studies demonstrated that porosity content and fraction of crystalline phase formation in the coatings were highly sensitive to spraying parameters. Increase in both the plasma power and coating thickness led to reduction in the porosity content and higher devitrification. Nanohardness of the coatings increased at elevated plasma power which was ascribed to the formation of denser coatings and precipitation of nano-sized Fe-borides, and therefore wear resistance of the coatings also improved. However, decrease in corrosion resistance was observed in the coatings deposited at the highest spraying power of 35 kW. Corrosion resistance improved with increasing coating thickness because of reduction in pore content, while formation of larger grains in thicker coatings caused decrease in nanohardness. Spraying power of 30 kW with three numbers of torch passes was found to be the optimum spraying parameters, and coating deposited at these parameters showed nanohardness value of 11 GPa, wear resistance coefficient of 49.9 × 1011 Pa and corrosion current density of 16 μA/cm2. This indicates that Fe-based Composite coating synthesized at optimized parameters could be a good alternative for industrial applications due to higher wear and corrosion resistance.
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Mechanical and corrosion properties of plasma-sprayed Fe-based amorphous/Nanocrystalline Composite coating
Advances in Materials and Processing Technologies, 2019Co-Authors: Anil Kumar, Sapan K. Nayak, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Tapas LahaAbstract:In this study, Fe-based amorphous/Nanocrystalline Composite coatings were synthesized with a cost-effective lean composition of Fe−2.5Cr−6.7Si−2.5B−0.7C (wt%) onto mild steel substrates. The effect...
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Fe-based amorphous/Nanocrystalline Composite coating by plasma spraying: Effect of heat input on morphology, phase evolution and mechanical properties
Journal of Alloys and Compounds, 2019Co-Authors: Anil Kumar, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Rahul Kumar, Tapas LahaAbstract:Abstract Fe-based amorphous/Nanocrystalline Composite coatings with a lean composition of Fe−2.5Cr−6.7Si−2.5B−0.7C (wt%) were synthesized by atmospheric plasma spraying (APS) onto a mild steel substrate. The effects of plasma power on the morphology and the phase content of the coatings were systematically investigated. Denser coatings with better inter-splat bonding were obtained at a higher plasma power, which was attributed to higher degree of powder melting. The retention of amorphous phase and formation of various Nanocrystalline Fe-borides in the amorphous matrix was decided by the variation in plasma power, which in turn affected the mechanical properties of the coatings. Increasing plasma power resulted in higher hardness and elastic modulus of the coatings, which is attributed to the compact microstructure of the coatings containing amorphous matrix with Nanocrystalline intermetallics (Fe23B6, Fe2B, and/or Fe3B) distributed. The nanoscratch results indicated that the increased plasma power resulted in uniform scratch profiles. Moreover, dry sliding wear test showed that both coefficient of friction and wear rate decreased with increasing plasma power. An analytical model was used to correlate mechanical and tribological properties of the coatings, which insinuated that the coating prepared at a plasma power of 35.5 kW exhibited significantly high shear strength than other coatings deposited at lower plasma power and approximately 3.6 times greater than that of the mild steel substrate.
Yoshio Sakka - One of the best experts on this subject based on the ideXlab platform.
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synthesis of dense Nanocrystalline zro2 mgal2o4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
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Synthesis of dense Nanocrystalline ZrO2–MgAl2O4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
Anil Kumar - One of the best experts on this subject based on the ideXlab platform.
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Multi-scale mechanical properties of Fe-based amorphous/Nanocrystalline Composite coating synthesized by HVOF spraying
Journal of Alloys and Compounds, 2020Co-Authors: Sapan K. Nayak, Abhishek Pathak, Atanu Banerjee, Anil Kumar, Tapas LahaAbstract:Abstract Fe-based (Fe–Cr–B–P–C) amorphous/Nanocrystalline Composite coatings were synthesized by high velocity oxy-fuel (HVOF) thermal spray method with varying powder feed rates and the multi-scale wear behaviour of the coatings' is reported here. Microstructural characterization of the Composite coating envisaged the presence of embedded Nanocrystalline phases in the amorphous matrix. The porosity content decreased, whereas the amorphicity of the coating increased gradually with increment in the feed rate. The combined effect of (i) splat morphology and (ii) extent of devitrification on the mechanical and tribological properties of the various coatings was investigated. Increasing the powder feed rate resulted in higher hardness of the coating, which was attributed to better inter-splat bonding and reduction in α-Fe content in the amorphous matrix of the coating due to lower extent of devitrification. Nanotribology test on a single-splat revealed increment in wear resistance at elevated feed rate due to the reduction in volume fraction of softer Nanocrystalline α-Fe phases. Besides, dry sliding wear investigated the coating's wear behaviour on a global basis and revealed decreasing trends for both wear rate and coefficient of friction with increasing feed rate. Most importantly, the Fe-based Composite coatings exhibited low wear volume during nanotribology and lower friction coefficient, low wear rate of dry sliding wear study, compared to an SS316L coating, prepared using industrially optimized parameters. The enhanced wear resistance of the Composite coating compared to that of the stainless steel coating makes it an effective method of surface protection for metallic substrates.
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A Study on the Corrosion Inhibition of Fe-Based Amorphous/Nanocrystalline Coating Synthesized by High-Velocity Oxy-Fuel Spraying in an Extreme Environment
Journal of Thermal Spray Technology, 2019Co-Authors: Sapan K. Nayak, Kuntal Sarkar, Abhishek Pathak, Atanu Banerjee, Anil Kumar, Tapas LahaAbstract:In this work, Fe-based (Fe-Cr-B-P-C) amorphous/Nanocrystalline Composite coatings were deposited by high-velocity oxy-fuel thermal spray method with varying powder feed rates and their behavior in saline environment was investigated. An SS316L coating with optimized parameters was also prepared for comparison purpose. The microstructural characterization of the Composite coatings revealed the presence of embedded Nanocrystalline phases in the amorphous matrix. The amorphicity of the coating increased, whereas the porosity content decreased gradually with the increment in feed rate during the spraying process. The combined effect of extent of devitrification and porosity content on the corrosion behavior of the various coatings was analyzed. Potentiodynamic polarization and electrochemical impedance spectroscopy studies revealed that the Fe-based Composite coatings exhibited significantly lower corrosion current density and higher polarization resistance than that of the mild steel substrate as well as SS316L coating. The enhanced corrosion resistance of the Composite coatings is ascribed to the combined effect of lower porosity content and retained amorphous phase. In addition, the formation of chromium hydroxide along with some of the oxides and hydroxides of iron in the post-corroded coating samples aids in impeding the corrosive solution penetration, thereby increasing the corrosion inhibition efficiency of the Composite coatings.Graphic Abstract
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Optimization of mechanical and corrosion properties of plasma sprayed low-chromium containing Fe-based amorphous/Nanocrystalline Composite coating
Surface & Coatings Technology, 2019Co-Authors: Anil Kumar, Sapan K. Nayak, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Tapas LahaAbstract:Abstract In this work, iron (Fe)-based amorphous/Nanocrystalline Composite coatings were synthesized using low-chromium containing amorphous powder (Fe73Cr2Si11B11C3, at. %) via atmospheric plasma spraying (APS) at different plasma spraying parameters. Coatings were deposited with 2 and 3 numbers of torch pass to get different coating thickness, along with the plasma power range was varied from 25 kW to 35 kW to alter the degree of powder melting. Microstructural studies demonstrated that porosity content and fraction of crystalline phase formation in the coatings were highly sensitive to spraying parameters. Increase in both the plasma power and coating thickness led to reduction in the porosity content and higher devitrification. Nanohardness of the coatings increased at elevated plasma power which was ascribed to the formation of denser coatings and precipitation of nano-sized Fe-borides, and therefore wear resistance of the coatings also improved. However, decrease in corrosion resistance was observed in the coatings deposited at the highest spraying power of 35 kW. Corrosion resistance improved with increasing coating thickness because of reduction in pore content, while formation of larger grains in thicker coatings caused decrease in nanohardness. Spraying power of 30 kW with three numbers of torch passes was found to be the optimum spraying parameters, and coating deposited at these parameters showed nanohardness value of 11 GPa, wear resistance coefficient of 49.9 × 1011 Pa and corrosion current density of 16 μA/cm2. This indicates that Fe-based Composite coating synthesized at optimized parameters could be a good alternative for industrial applications due to higher wear and corrosion resistance.
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Mechanical and corrosion properties of plasma-sprayed Fe-based amorphous/Nanocrystalline Composite coating
Advances in Materials and Processing Technologies, 2019Co-Authors: Anil Kumar, Sapan K. Nayak, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Tapas LahaAbstract:In this study, Fe-based amorphous/Nanocrystalline Composite coatings were synthesized with a cost-effective lean composition of Fe−2.5Cr−6.7Si−2.5B−0.7C (wt%) onto mild steel substrates. The effect...
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Fe-based amorphous/Nanocrystalline Composite coating by plasma spraying: Effect of heat input on morphology, phase evolution and mechanical properties
Journal of Alloys and Compounds, 2019Co-Authors: Anil Kumar, Atanu Banerjee, Pavan Bijalwan, Monojit Dutta, Rahul Kumar, Tapas LahaAbstract:Abstract Fe-based amorphous/Nanocrystalline Composite coatings with a lean composition of Fe−2.5Cr−6.7Si−2.5B−0.7C (wt%) were synthesized by atmospheric plasma spraying (APS) onto a mild steel substrate. The effects of plasma power on the morphology and the phase content of the coatings were systematically investigated. Denser coatings with better inter-splat bonding were obtained at a higher plasma power, which was attributed to higher degree of powder melting. The retention of amorphous phase and formation of various Nanocrystalline Fe-borides in the amorphous matrix was decided by the variation in plasma power, which in turn affected the mechanical properties of the coatings. Increasing plasma power resulted in higher hardness and elastic modulus of the coatings, which is attributed to the compact microstructure of the coatings containing amorphous matrix with Nanocrystalline intermetallics (Fe23B6, Fe2B, and/or Fe3B) distributed. The nanoscratch results indicated that the increased plasma power resulted in uniform scratch profiles. Moreover, dry sliding wear test showed that both coefficient of friction and wear rate decreased with increasing plasma power. An analytical model was used to correlate mechanical and tribological properties of the coatings, which insinuated that the coating prepared at a plasma power of 35.5 kW exhibited significantly high shear strength than other coatings deposited at lower plasma power and approximately 3.6 times greater than that of the mild steel substrate.
K Morita - One of the best experts on this subject based on the ideXlab platform.
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synthesis of dense Nanocrystalline zro2 mgal2o4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
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Synthesis of dense Nanocrystalline ZrO2–MgAl2O4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
Hidehiro Yoshida - One of the best experts on this subject based on the ideXlab platform.
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Superplasticity of Nanocrystalline ZrO2-Spinel Composite
Key Engineering Materials, 2007Co-Authors: Koji Morita, Keijiro Hiraga, Hidehiro YoshidaAbstract:The effect of nanocrystalization on superplastic flow was examined in ZrO2-30vol%spinel Composite. The nanocrystalization can increase the strain rate by one order of magnitude or lower the deforming temperature by about 100 K. Irrespective of the lowered flow stress, however, the tensile elongation to failure of Nanocrystalline Composite is lower than that of submicrom-grain Composite. The limited tensile elongation in Nanocrystalline Composite can be ascribed mainly to accelerating cavity damage accumulation.
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synthesis of dense Nanocrystalline zro2 mgal2o4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
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Synthesis of dense Nanocrystalline ZrO2–MgAl2O4 spinel Composite
Scripta Materialia, 2005Co-Authors: K Morita, Keijiro Hiraga, Hidehiro Yoshida, Yoshio SakkaAbstract:Abstract A Nanocrystalline ZrO 2 –spinel Composite with an average grain size of smaller than 100 nm can be synthesized by high-energy ball-milling followed by spark plasma sintering. Nanocrystallization can strengthen the ZrO 2 –spinel Composite by a factor of 2.0–2.5; the maximum flexural strength of the Nanocrystalline Composite reached ≈2200 MPa.
