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Analysis of MgO Nano Particles and Its Deposition on Steel by Cold Spray Process
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 5 (2018) 19262–19269
www.materialstoday.com/proceedings
ICMPC_2018
Analysis of MgO Nano Particles and Its Deposition on Steel by Cold Spray Process Pulla Sammaiaha, B. Vineetha a1, A. Suresh b, Ch.Sushanthc, N.Sudheer Kumar c* a1
M.Tech (15K41D301), Department of Mechanical Engineering, SR Engineering Collage, Warangal, Telangana-560371. a Research Dean, Department of Mechanical Engineering, SR Engineering Collage, Warangal, Telangana-560371. b Research scholar, Department of Mechanical Engineering, JNTUH, Hyderabad, Telangana-560001. c* Assistant Professor, Department of Mechanical Engineering, SVS Group of Institutions, Warangal, Telangana-560371.
Abstract In the present scenario, steel has become an important part of industry due to its extensive applications in automotive, household appliances, business machine and heavy construction such as marine and chemical industries. Magnesium oxide nano particles are odourless and nontoxic. They possess high hardness, high purity and a high melting point. It is the popular material used in the applications automotive, aerospace, sports equipment, and electronics industries. Heat treated mild steel at 800˚C shows rough surface roughness and shows fine surface when compared with 600˚C. Surface roughness is higher after deposition of MgO nano particles on mild steel at 800˚C when compared with 600˚C. Surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal. The hardness of the base metal is low when compared with heat treated mild steel at 600˚C. Heat treated mild steel at 800˚C shows high hardness when compared with base metal. The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚C. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization. Keywords: Airbrush device, Rockwell hardness, surface roughness, XRD and SEM..
1. Introduction Now a day’s stainless steel is widely known to have superior mechanical, tribological and corrosion properties and it has become an important part of our life due to its extensive applications in automotive and heavy constructions such as marine and chemical industries [1]. Mild steel is selected for construction because of its mechanical properties and machine-ability at a low price [2]. * Corresponding author. Tel:
E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization.
Pulla Sammaiah et al./ Materials Today: Proceedings 5 (2018) 19262–19269
19263
While at the same time; they have to be resisted against corrosion phenomena [3]. For the better protection of stainless steel, the metallic coatings such as MgO nano particles are coated at different heat treated conditions [4].For this study, MgO nano particles were done by solution combustion process and size was found to be 38 nm from X-Ray Diffraction (XRD). Plate samples (10X15X2 mm) are heat treated at 600˚C and 800˚C in muffle furnace, prepared nano particles are coated on mild steel plate by using Airbrush device. At 800˚C the samples shows better surface roughness because of uniform deposition of nano particles and coated samples are characterized by Scanning Electron Microscopy (SEM), Rockwell hardness. 2. Experimental Details 2.1 Material Used: MgO nano particles Mild steel plate (10 x 15 x 2 mm) Magnesium Nitrate (Mg(NO3)2 Ascorbic acid (C6H8O6) 2.2 Synthesis of Al2O3 Nano particles: Magnesium Oxide is prepared by Solution combustion process. Stoichiometric amounts of Magnesium Nitrate and L-Ascorbic acid are taken into beaker and stirred it for 30 minutes on a magnetic stirrer and place it on a hot plate (~1000°c). + 2 C H O 2mgO 4H O 6CO 2N Heating rapidly the solution containing the redox mixture boils, frothing, smouldering, flaming, fumes and catches fire and burns with an in candescent flame to yield MgO with evolution of large amount of gases like carbon dioxide, Hydrogen Oxide in the form of flames. This procedure was done in open air instead of doing it in closed vessel.
Figure: 1(a) Magnesium nitrate, 1(b) Ascorbic acid, 1(c) hot plate, 1(d) Combustion stage 1(e) Muffle furnace for calcinations, 1(f) After calcinations of nano particles
2.3Scanning Electron Microscopy: The grain size, shape and surface properties like morphology were observed by the SEM(HITACHI S3400NS) machine at different magnifications. The SEM images of MgO nanoparticles are prepared by solution combustion process as shown in the figure 1. 2.4 Energy Dispersive X-ray Spectroscopy: The EDX of MgO nano particles was done by the SEM (HITACHI S3400NS) machine. It reveals that the composition present in the sample. 2.5 Surface Roughness: After heat treatment the samples at different temperatures the surface roughness of the base metals are tested by using SJ-310 Portable Surface Roughness Tester. And after spraying MgO nano particles on metals again the samples are tested for surface roughness Table 1.
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Pulla Sammaiah et al./ Materials Today: Proceedings 5 (2018) 19262–19269 Table 1: Surface Roughness at different temperatures of the samples Surfance Roughness, Micro Meters S.NO
Base Metal
After Tratment at
After Heat
Deposition of Mgo
Deposition of Mgo
600 0C
Treatment at 800 0C
nano Particles at
nano Particles at
600 0C
800 0C
1
1.355
1.054
1.154
0.797
0.856
2
1.764
1.659
1.854
1.044
1.035
Avg.
3.119
2.713
3.008
1.841
1.891
2.5 Rockwell hardness: After heat treating the samples at different temperatures, the base metal and heat treated samples are tested for Rockwell hardness. After spraying MgO nano particles on the mild steel again the samples are tested for hardness as shown in the table 2. Table 2: hardness values at different conditions
S.NO
Base Metal
After Tratment at 0
After Heat 0
600 C
Treatment at 800 C
Deposition of Mgo
Deposition of Mgo
nano Particles at
nano Particles at 800 0C 70
1
66
66
69
600 0C 68
2
55
59
62
64
66
3
67
66
69
69
68
4
68
69
68
67
67
5
62
64
66
68
68
Avg
63.6
64.8
66.8
67.2
67.8
2.7 Coating Technique by Airbrush: An air brush of model NX-A&NX-B NEW YORK was used for coating MgO nano particles on mild steel at different temperatures as shown in the figure 2. Prepared nano particles are taken into the air brush reservoir, hose connector is connected to compressor and the air brush uses a pressure of 2 to 2.4 bars. As the force applied on the trigger a stream of fast moving air through a venture, which creates a local reduction air pressure, that allows the particles to pull up from an interconnected reservoir at normal atmospheric pressure. The high velocity of the air carries the MgO nano particles and impinges on the mild steel.
Figure 2: Spraying Process
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3. Results and Discuss: 3.1 X-Ray Diffraction: In the XRD pattern of the MgO nano particles, the peaks are observed at 37.062, 43.060 and 62.529 (h k l) values of the peaks are (1 1 1), (2 0 0) and (2 2 0)respectively. These results are coincided with JCPDS card number 75-1525, and it shows that the MgO nano particles consists the cubic structure. The average crystalline size is measured using Debye-Scherer’s formula [5].
Figure 3: XRD pattern of MgO nano particles
According to the Debye-Scherer’s equation: D
0.9λ nm βcosθ
Where D – Average size of the particle [nm] --Wavelength of the radiation [A°] θ –Diffraction angle [degree] B – Full width half maximum (FWHM) of the peak [radians] From the above formula obtained average crystalline size is 38 nm. The lattice parameter a = b = 4.760 A°, c = 12.994 A°. 3.2 Scanning Electron Microscopy: The grain size, shape and surface properties like morphology were observed by the SEM with different magnifications. Grain size of MgO nano particles were nearly 233 nm and the particles exhibit agglomeration like structure due to some excess elements present in it. As shown in below Fig 4.
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Figure 4: SEM image of MgO nano particle
3.3 EDX of MgO nano particles: The EDX of the MgO sample was done by the SEM (HITACHI S3400NS) machine. The Energy dispersive X-ray spectroscopy reveals that the required phase has present. Magnesium (Mg) and Oxygen (O) elements are present in the sample as shown below Table 3 and Fig 5.
Figure 5: EDX image of MgO nano particle
Table 3: Composition of MgO nano particle S.NO
Elememnts
Weight%
1
Magnesium
51.42
2
Oxygen
48.58
3.4 SEM Images of coated MgO nano particles on mild steel: SEM images of coated MgO nano particles on mild steel at different temperatures 600˚ C and 800˚ C were shown in the figure 6 (a) & (b). The grain size, shape and surface properties like morphology were observed by the SEM with different magnification. Coated nano particles on mild steel at 800˚ C, shows respectable morphology when compared with coated nano particles on mild steel at 600˚ C. Grain size of coated samples were nearly 204 nm and 440 nm for 600˚ C and 800˚ C temperatures and the shapes of the coated samples at 600˚ C and 800˚ C was spherical and regular manner.
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Figure 6(a) &(b): SEM images of coated MgO nano particles on mild steel at 600˚ C &800˚ C
3.5 EDX of coated MgO nano particles: The elemental composition of coated samples at different temperatures as shown in the figure 7 (a) & (b). The EDX pattern shows that the coated sample at 600˚ C shows less Magnesium percentage along with Iron, Carbon and Oxygen whereas for coated samples at 800˚ C shows more Magnesium percentage along with Iron, Carbon and Oxygen. Its shows the deposition rate of Magnesium is high at 800˚ C when compared with 600˚ C as shown in the table 4.
Figure 7 (a) & (b): EDX images of coated MgO nano particles
Table 4: Elemental Composition of coated samples at different temperatures: 600 0C
Compositio
8000C
S.NO
Element
Weight
Element
1
C
11.27
C
Weight 5.45
2
0
10.98
0
10.98
3
Mg
38.04
Mg
47.08
4
Fe
36.54
Fe
30.67
5
Total
100
Total
100
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3.6 Surface Roughness: Initially the surface roughness of the base metal is high when compared with heat treated sample at 600˚C due to the heat treatment the surface roughness of the sample is smooth. Heat treated sample at 800˚C shows fine surface roughness when compared with base metal due to the recrystallization temperature at 723˚C (i.e. new grains starts forming) and shows rough surface compared to 600˚C due to scale formation and high rate of deformation. Surface roughness is high after deposition of MgO nano particles on mild steel at 800˚C, due to high bond generated between MgO and mild steel at recrystallization temperature (i.e. 723˚C) when compared with deposition of nano particles on mild steel at 600˚C (Figure 7). Surface roughness is lower after deposition of nano particles on mild steel at 800˚ C (Figure 7)when compared with untreated metal because of the bond generated during coating process. Surface roughness is lower after deposition of MgO nano particles on mild steel at 600˚C when compared with base metal because of uniform deposition of MgO nano particles. During coating process surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal because of uniform deposition of MgO nano particles during coating process. 3.7 Rockwell Hardness: The behaviour of the hardness variation with different temperatures conditions (i.e. before coating and after coating). The hardness of the base metal is low when compared with heat treated sample at 600˚ C, due to the heat treatment process as shown in Figure 8.Heat treated sample at 800˚ C shows high hardness when compared with base metal due to the formation of new grains at recrystallation temperature (Figure 6). The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚C due to high friction generated which results good reaction between MgO nano particles and Mild steel. The same trend happened after coating nano particles on mild steel at 600˚C due to microstructure shows particle size 38nm as shown in Figure 6. But before coating, the hardness is moderate when compared with coated samples and base metal.
Figure 8: Hardness variations with heat treated and spraying process
4. Conclusions: The mild steel at 800˚C shows fine surface roughness when compared with base metal and shows rough surface compared to 600˚C. Surface roughness is high after deposition of MgO nano particles on mild steel at 800˚C, due to high bond generated between MgO and mild steel at recrystallization temperature (i.e. 723˚C) when compared with deposition of nano particles on mild steel at 600˚C . Surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal because of uniform deposition of nano particles during coating process.
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The hardness of the base metal is low when compared with heat treated sample at 600˚ C, due to the heat treatment process. Heat treated mild steel at 800˚ C shows high hardness when compared with base metal due to the formation of new grains at recrystallization temperature. The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚ C due to high friction generated which results good reaction between MgO nano particles and Mild steel. 5. References: [1] Sadiq, I. M., Chowdhury, B., Chandrasekaran, N. and Mukherjee, A.,"Antimicrobial sensitivity of Escherichia coli to alumina nanoparticles", Nanomedicine: Nanotechnology, Biology and Medicine, Vol. 5, No. 3, pp. 282-286 [2] E. Bardel, Corrosion and Protection, Springer-Verlag, London, 2003. [3] P.R. Roberge, Handbook of Corrosion Engineering, McGraw-Hill, New York,1999. [4] Gupta, M., Lai, M.O. and Saravanaranganathan, D. (2000). Synthesis, Microstructure and Properties Characterization of Disintegrated Melt Deposited Mg/SiC Composites, J. Mater. Sci., 35: 2155–2165. [5] N. Sudheerkumar, P. Sammaiah, K. Venkateswara Rao, M. Sneha and CH. Ashok, Influence of nano solid lubricant emulsions on surface roughness of mild steel when on lathe machine, ELSEVIER, (www.sciencedirect.com) Materials Today: Proceedings 2(2015) 4413-4420, DOI: 10.1016/j.matpr.2015.10.042.
ScienceDirect Materials Today: Proceedings 5 (2018) 19262–19269
www.materialstoday.com/proceedings
ICMPC_2018
Analysis of MgO Nano Particles and Its Deposition on Steel by Cold Spray Process Pulla Sammaiaha, B. Vineetha a1, A. Suresh b, Ch.Sushanthc, N.Sudheer Kumar c* a1
M.Tech (15K41D301), Department of Mechanical Engineering, SR Engineering Collage, Warangal, Telangana-560371. a Research Dean, Department of Mechanical Engineering, SR Engineering Collage, Warangal, Telangana-560371. b Research scholar, Department of Mechanical Engineering, JNTUH, Hyderabad, Telangana-560001. c* Assistant Professor, Department of Mechanical Engineering, SVS Group of Institutions, Warangal, Telangana-560371.
Abstract In the present scenario, steel has become an important part of industry due to its extensive applications in automotive, household appliances, business machine and heavy construction such as marine and chemical industries. Magnesium oxide nano particles are odourless and nontoxic. They possess high hardness, high purity and a high melting point. It is the popular material used in the applications automotive, aerospace, sports equipment, and electronics industries. Heat treated mild steel at 800˚C shows rough surface roughness and shows fine surface when compared with 600˚C. Surface roughness is higher after deposition of MgO nano particles on mild steel at 800˚C when compared with 600˚C. Surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal. The hardness of the base metal is low when compared with heat treated mild steel at 600˚C. Heat treated mild steel at 800˚C shows high hardness when compared with base metal. The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚C. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization. Keywords: Airbrush device, Rockwell hardness, surface roughness, XRD and SEM..
1. Introduction Now a day’s stainless steel is widely known to have superior mechanical, tribological and corrosion properties and it has become an important part of our life due to its extensive applications in automotive and heavy constructions such as marine and chemical industries [1]. Mild steel is selected for construction because of its mechanical properties and machine-ability at a low price [2]. * Corresponding author. Tel:
E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization.
Pulla Sammaiah et al./ Materials Today: Proceedings 5 (2018) 19262–19269
19263
While at the same time; they have to be resisted against corrosion phenomena [3]. For the better protection of stainless steel, the metallic coatings such as MgO nano particles are coated at different heat treated conditions [4].For this study, MgO nano particles were done by solution combustion process and size was found to be 38 nm from X-Ray Diffraction (XRD). Plate samples (10X15X2 mm) are heat treated at 600˚C and 800˚C in muffle furnace, prepared nano particles are coated on mild steel plate by using Airbrush device. At 800˚C the samples shows better surface roughness because of uniform deposition of nano particles and coated samples are characterized by Scanning Electron Microscopy (SEM), Rockwell hardness. 2. Experimental Details 2.1 Material Used: MgO nano particles Mild steel plate (10 x 15 x 2 mm) Magnesium Nitrate (Mg(NO3)2 Ascorbic acid (C6H8O6) 2.2 Synthesis of Al2O3 Nano particles: Magnesium Oxide is prepared by Solution combustion process. Stoichiometric amounts of Magnesium Nitrate and L-Ascorbic acid are taken into beaker and stirred it for 30 minutes on a magnetic stirrer and place it on a hot plate (~1000°c). + 2 C H O 2mgO 4H O 6CO 2N Heating rapidly the solution containing the redox mixture boils, frothing, smouldering, flaming, fumes and catches fire and burns with an in candescent flame to yield MgO with evolution of large amount of gases like carbon dioxide, Hydrogen Oxide in the form of flames. This procedure was done in open air instead of doing it in closed vessel.
Figure: 1(a) Magnesium nitrate, 1(b) Ascorbic acid, 1(c) hot plate, 1(d) Combustion stage 1(e) Muffle furnace for calcinations, 1(f) After calcinations of nano particles
2.3Scanning Electron Microscopy: The grain size, shape and surface properties like morphology were observed by the SEM(HITACHI S3400NS) machine at different magnifications. The SEM images of MgO nanoparticles are prepared by solution combustion process as shown in the figure 1. 2.4 Energy Dispersive X-ray Spectroscopy: The EDX of MgO nano particles was done by the SEM (HITACHI S3400NS) machine. It reveals that the composition present in the sample. 2.5 Surface Roughness: After heat treatment the samples at different temperatures the surface roughness of the base metals are tested by using SJ-310 Portable Surface Roughness Tester. And after spraying MgO nano particles on metals again the samples are tested for surface roughness Table 1.
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Pulla Sammaiah et al./ Materials Today: Proceedings 5 (2018) 19262–19269 Table 1: Surface Roughness at different temperatures of the samples Surfance Roughness, Micro Meters S.NO
Base Metal
After Tratment at
After Heat
Deposition of Mgo
Deposition of Mgo
600 0C
Treatment at 800 0C
nano Particles at
nano Particles at
600 0C
800 0C
1
1.355
1.054
1.154
0.797
0.856
2
1.764
1.659
1.854
1.044
1.035
Avg.
3.119
2.713
3.008
1.841
1.891
2.5 Rockwell hardness: After heat treating the samples at different temperatures, the base metal and heat treated samples are tested for Rockwell hardness. After spraying MgO nano particles on the mild steel again the samples are tested for hardness as shown in the table 2. Table 2: hardness values at different conditions
S.NO
Base Metal
After Tratment at 0
After Heat 0
600 C
Treatment at 800 C
Deposition of Mgo
Deposition of Mgo
nano Particles at
nano Particles at 800 0C 70
1
66
66
69
600 0C 68
2
55
59
62
64
66
3
67
66
69
69
68
4
68
69
68
67
67
5
62
64
66
68
68
Avg
63.6
64.8
66.8
67.2
67.8
2.7 Coating Technique by Airbrush: An air brush of model NX-A&NX-B NEW YORK was used for coating MgO nano particles on mild steel at different temperatures as shown in the figure 2. Prepared nano particles are taken into the air brush reservoir, hose connector is connected to compressor and the air brush uses a pressure of 2 to 2.4 bars. As the force applied on the trigger a stream of fast moving air through a venture, which creates a local reduction air pressure, that allows the particles to pull up from an interconnected reservoir at normal atmospheric pressure. The high velocity of the air carries the MgO nano particles and impinges on the mild steel.
Figure 2: Spraying Process
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3. Results and Discuss: 3.1 X-Ray Diffraction: In the XRD pattern of the MgO nano particles, the peaks are observed at 37.062, 43.060 and 62.529 (h k l) values of the peaks are (1 1 1), (2 0 0) and (2 2 0)respectively. These results are coincided with JCPDS card number 75-1525, and it shows that the MgO nano particles consists the cubic structure. The average crystalline size is measured using Debye-Scherer’s formula [5].
Figure 3: XRD pattern of MgO nano particles
According to the Debye-Scherer’s equation: D
0.9λ nm βcosθ
Where D – Average size of the particle [nm] --Wavelength of the radiation [A°] θ –Diffraction angle [degree] B – Full width half maximum (FWHM) of the peak [radians] From the above formula obtained average crystalline size is 38 nm. The lattice parameter a = b = 4.760 A°, c = 12.994 A°. 3.2 Scanning Electron Microscopy: The grain size, shape and surface properties like morphology were observed by the SEM with different magnifications. Grain size of MgO nano particles were nearly 233 nm and the particles exhibit agglomeration like structure due to some excess elements present in it. As shown in below Fig 4.
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Figure 4: SEM image of MgO nano particle
3.3 EDX of MgO nano particles: The EDX of the MgO sample was done by the SEM (HITACHI S3400NS) machine. The Energy dispersive X-ray spectroscopy reveals that the required phase has present. Magnesium (Mg) and Oxygen (O) elements are present in the sample as shown below Table 3 and Fig 5.
Figure 5: EDX image of MgO nano particle
Table 3: Composition of MgO nano particle S.NO
Elememnts
Weight%
1
Magnesium
51.42
2
Oxygen
48.58
3.4 SEM Images of coated MgO nano particles on mild steel: SEM images of coated MgO nano particles on mild steel at different temperatures 600˚ C and 800˚ C were shown in the figure 6 (a) & (b). The grain size, shape and surface properties like morphology were observed by the SEM with different magnification. Coated nano particles on mild steel at 800˚ C, shows respectable morphology when compared with coated nano particles on mild steel at 600˚ C. Grain size of coated samples were nearly 204 nm and 440 nm for 600˚ C and 800˚ C temperatures and the shapes of the coated samples at 600˚ C and 800˚ C was spherical and regular manner.
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Figure 6(a) &(b): SEM images of coated MgO nano particles on mild steel at 600˚ C &800˚ C
3.5 EDX of coated MgO nano particles: The elemental composition of coated samples at different temperatures as shown in the figure 7 (a) & (b). The EDX pattern shows that the coated sample at 600˚ C shows less Magnesium percentage along with Iron, Carbon and Oxygen whereas for coated samples at 800˚ C shows more Magnesium percentage along with Iron, Carbon and Oxygen. Its shows the deposition rate of Magnesium is high at 800˚ C when compared with 600˚ C as shown in the table 4.
Figure 7 (a) & (b): EDX images of coated MgO nano particles
Table 4: Elemental Composition of coated samples at different temperatures: 600 0C
Compositio
8000C
S.NO
Element
Weight
Element
1
C
11.27
C
Weight 5.45
2
0
10.98
0
10.98
3
Mg
38.04
Mg
47.08
4
Fe
36.54
Fe
30.67
5
Total
100
Total
100
19268
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3.6 Surface Roughness: Initially the surface roughness of the base metal is high when compared with heat treated sample at 600˚C due to the heat treatment the surface roughness of the sample is smooth. Heat treated sample at 800˚C shows fine surface roughness when compared with base metal due to the recrystallization temperature at 723˚C (i.e. new grains starts forming) and shows rough surface compared to 600˚C due to scale formation and high rate of deformation. Surface roughness is high after deposition of MgO nano particles on mild steel at 800˚C, due to high bond generated between MgO and mild steel at recrystallization temperature (i.e. 723˚C) when compared with deposition of nano particles on mild steel at 600˚C (Figure 7). Surface roughness is lower after deposition of nano particles on mild steel at 800˚ C (Figure 7)when compared with untreated metal because of the bond generated during coating process. Surface roughness is lower after deposition of MgO nano particles on mild steel at 600˚C when compared with base metal because of uniform deposition of MgO nano particles. During coating process surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal because of uniform deposition of MgO nano particles during coating process. 3.7 Rockwell Hardness: The behaviour of the hardness variation with different temperatures conditions (i.e. before coating and after coating). The hardness of the base metal is low when compared with heat treated sample at 600˚ C, due to the heat treatment process as shown in Figure 8.Heat treated sample at 800˚ C shows high hardness when compared with base metal due to the formation of new grains at recrystallation temperature (Figure 6). The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚C due to high friction generated which results good reaction between MgO nano particles and Mild steel. The same trend happened after coating nano particles on mild steel at 600˚C due to microstructure shows particle size 38nm as shown in Figure 6. But before coating, the hardness is moderate when compared with coated samples and base metal.
Figure 8: Hardness variations with heat treated and spraying process
4. Conclusions: The mild steel at 800˚C shows fine surface roughness when compared with base metal and shows rough surface compared to 600˚C. Surface roughness is high after deposition of MgO nano particles on mild steel at 800˚C, due to high bond generated between MgO and mild steel at recrystallization temperature (i.e. 723˚C) when compared with deposition of nano particles on mild steel at 600˚C . Surface roughness is low after deposition of MgO nano particles on mild steel at 600˚ C when compared with base metal because of uniform deposition of nano particles during coating process.
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The hardness of the base metal is low when compared with heat treated sample at 600˚ C, due to the heat treatment process. Heat treated mild steel at 800˚ C shows high hardness when compared with base metal due to the formation of new grains at recrystallization temperature. The hardness of the coated sample at 600˚C is moderate when compared with base metal due to deposition of MgO nano particles on mild steel. When compared with base metal the coated sample at 800˚C shows high hardness because of maximum deposition of MgO nano particles on mild steel. The hardness is high after coating nano particles on mild steel at 800˚ C due to high friction generated which results good reaction between MgO nano particles and Mild steel. 5. References: [1] Sadiq, I. M., Chowdhury, B., Chandrasekaran, N. and Mukherjee, A.,"Antimicrobial sensitivity of Escherichia coli to alumina nanoparticles", Nanomedicine: Nanotechnology, Biology and Medicine, Vol. 5, No. 3, pp. 282-286 [2] E. Bardel, Corrosion and Protection, Springer-Verlag, London, 2003. [3] P.R. Roberge, Handbook of Corrosion Engineering, McGraw-Hill, New York,1999. [4] Gupta, M., Lai, M.O. and Saravanaranganathan, D. (2000). Synthesis, Microstructure and Properties Characterization of Disintegrated Melt Deposited Mg/SiC Composites, J. Mater. Sci., 35: 2155–2165. [5] N. Sudheerkumar, P. Sammaiah, K. Venkateswara Rao, M. Sneha and CH. Ashok, Influence of nano solid lubricant emulsions on surface roughness of mild steel when on lathe machine, ELSEVIER, (www.sciencedirect.com) Materials Today: Proceedings 2(2015) 4413-4420, DOI: 10.1016/j.matpr.2015.10.042.