57 Chapter Chapter Chapter Chapter - III III III III Corrosion Behavio Corrosion Behavio Corrosion Behavio Corrosion Behaviour of Iron r of Iron r of Iron r of Iron- base Alloys in Presence of base Alloys in Presence of base Alloys in Presence of base Alloys in Presence of Dissolved Copper Dissolved Copper Dissolved Copper Dissolved Copper
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
57
Chapter Chapter Chapter Chapter ---- IIIIIIIIIIII
Corrosion BehavioCorrosion BehavioCorrosion BehavioCorrosion Behaviouuuur of Ironr of Ironr of Ironr of Iron----
base Alloys in Presence of base Alloys in Presence of base Alloys in Presence of base Alloys in Presence of
Table 3.13 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for mild steel immersed in distilled
water at pH 4.0
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 24hrs 360hrs 720hrs
Aerated Static Blank - - -
„ 0.01 0.0 0.0 0.0
„ 0.1 0.0 0.0 0.0
„ 1 0.0 0.0 0.0
„ 10 0.0 0.0 0.0
„ 20 2.0 0.1 0.0
„ 30 7.0 0.9 0.0
„ 40 18.0 1.5 0.0
„ 100 13.0 2.4 0.4
Deaerated Static* Blank - - -
„ 0.1 0.0 - -
„ 1 0.0 - -
„ 100 72.0 - -
* 12 hrs.
89
Table 3.14 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for mild steel immersed in distilled water at
pH 6.5
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 24hrs 360hrs 720hrs
Aerated Static Blank - - -
„ 0.01 0.0 0.0 0.0
„ 0.1 0.0 0.0 0.0
„ 1 0.0 0.0 0.0
„ 10 0.0 0.0 0.0
„ 20 6.0 0.4 0.0
„ 30 10.0 1.2 0.0
„ 40 20.0 2.0 0.0
„ 100 30.0 4.9 0.1
Deaerated Static* Blank - - -
„ 0.1 0.0 - -
„ 1 0.0 - -
„ 100 76.0 - -
* 12 hrs.
90
Table 3.15 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for mild steel immersed in distilled
water at pH 8.5
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the test
solutions before
commencement of
immersion (ppm) 24hrs 360hrs 720hrs
Aerated Static Blank - - -
„ 0.01 0.0 0.0 0.0
„ 0.1 0.0 0.0 0.0
„ 1 0.0 0.0 0.0
„ 10 0.0 0.0 0.0
„ 20 5.0 0.0 0.0
„ 30 19.0 1.8 0.0
„ 40 30.0 2.3 0.0
„ 100 50.0 7.0 0.2
Deaerated Static* Blank - - -
„ 0.1 0.0 - -
„ 1 0.0 - -
„ 100 80.0 - -
* 12 hrs.
91
Table 3.16 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for mild steel immersed in artificial
seawater at pH 8.2
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 24hrs 360hrs 720hrs
Aerated Static Blank - - -
„ 0.01 - - -
„ 0.1 - - -
„ 1 0.0 0.0 0.0
„ 10 2.1 0.9 0.0
„ 20 8.9 1.5 0.2
„ 30 12.7 5.3 0.9
„ 40 29.1 10.4 5.3
„ 100 63.5 14.7 3.2
Deaerated Static* Blank - - -
„ 0.1 0.0 - -
„ 1 0.0 - -
„ 100 86.0 - -
* 12 hrs.
92
Table 3.17 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 304L immersed in distilled
water at pH 4.0
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.9 0.9
„ 10 9.0 8.2 8.1
„ 20 18.0 18.0 17.8
„ 30 27.0 26.3 27.0
„ 40 36.0 38.0 36.9
„ 100 57.0 38.0 37.0
Table 3.18 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 304L immersed in distilled
water at pH 6.5
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.7 0.7
„ 10 9.2 9.1 8.8
„ 20 18.0 17.0 17.7
„ 30 28.0 26.3 28.0
„ 40 38.0 37.0 37.5
„ 100 52.0 36.0 35.8
93
Table 3.19 Concentrations of Cu ions as estimated by AAS in the test solutions
completion of immersion for SS 304L immersed in distilled water at
pH 8.5
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320
hrs
8760 hrs
Aerated Static Blank - - -
„ 1 0.7 0.7 0.7
„ 10 8.1 7.9 8.7
„ 20 19.0 18.0 18.2
„ 30 29.0 27.0 28.1
„ 40 38.0 37.0 37.0
„ 100 55.0 47.0 46.9
Table 3.20 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 304L immersed in artificial
seawater at pH 8.2
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions
before
commencement of
immersion (ppm)
720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.8 0.8
„ 10 8.3 8.2 8.7
„ 20 19.0 18.0 18.0
„ 30 28.0 27.0 28.1
„ 40 37.0 36.0 38.6
„ 100 49.0 39.0 38.0
94
Table 3.21 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 316L immersed in distilled
water at pH 4.0
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.0 0.0
„ 10 9.1 8.8 8.6
„ 20 19.1 18.9 18.1
„ 30 29.1 28.7 28.0
„ 40 37.8 37.1 36.4
„ 100 96.7 95.1 93.0
Table 3.22 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 316L immersed in distilled
water at pH 6.5
Cu ions conc. in the test solutions
after completion of immersion
(ppm)
Flow condition
Cu ions conc. in the
test solutions
before
commencement of
immersion (ppm)
720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.0 0.0
„ 10 9.7 9.5 9.1
„ 20 19.7 19.6 19.4
„ 30 29.8 28.9 28.5
„ 40 38.7 38.2 35.9
„ 100 98.1 96.8 91.0
95
Table 3.23 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 316L immersed in distilled
water at pH 8.5
Cu ions conc. in the test
solutions after completion of
immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.8 0.8 0.7
„ 10 9.1 8.9 8.6
„ 20 19.5 18.9 18.4
„ 30 29.0 28.8 28.3
„ 40 39.6 38.8 38.2
„ 100 97.9 97.3 96.0
Table 3.24 Concentrations of Cu ions as estimated by AAS in the test solutions
after completion of immersion for SS 304L immersed in artificial
seawater at pH 8.2
Cu ions conc. in the test
solutions after completion
of immersion (ppm)
Flow condition
Cu ions conc. in the
test solutions before
commencement of
immersion (ppm) 720 hrs 4320 hrs 8760 hrs
Aerated Static Blank - - -
„ 1 0.9 0.9 0.8
„ 10 9.6 9.1 8.9
„ 20 19.7 19.6 18.8
„ 30 29.3 28.6 28.5
„ 40 39.7 39.1 38.6
„ 100 99.1 98.2 94.0
96
Table 3.25 Corrosion parameters for mild steel immersed in distilled water and
artificial seawater as obtained by potentiodynamic polarization
measurements
Aqueous medium pH Cu ions
conc. (ppm) Ecorr (mv) Icorr (A/cm
2)
Blank -610 4.7×10-4
1 -628 2.4×10-4 4.0
100 -584 1.1×10-3
Blank -568 5.5×10-5
1 -552 5.1×10-5 6.5
100 -720 9.4×10-4
Blank -528 1.0×10-4
1 -562 8.3×10-5
Distilled water
8.5
100 -728 2.6×10-5
Blank -849 2.8×10-5
1 -831 1.9×10-5 Artificial seawater 8.2
100 -818 3.2×10-5
Table 3.26 Corrosion parameters for SS 304L immersed in distilled water and
artificial seawater as obtained by potentiodynamic polarization
measurements
Aqueous
medium pH
Cu ions
conc. (ppm) Ecorr (mv) Icorr (A/cm
2)
Blank -102 2.5×10-6
1 -98 2.4×10-6 4.0
100 -13 3.6×10-6
Blank -151 1.0×10-7
1 +29 2.4×10-7 6.5
100 +69 7.9×10-6
Blank -97 1.3×10-7
1 -149 8.7×10-8
Distilled water
8.5
100 +74 1.8×10-7
97
Figure 3.1: pH vs. time plot in absence and presence of varying concentration of Cu ions for mild steel immersed in distilled water at pH 4.0.
Figure 3.2: pH vs. time plot in absence and presence of varying concentration of Cu ions for mild steel immersed in distilled water at pH 6.5.
98
Figure 3.3: pH vs. time plot in absence and presence of varying concentration of
Cu ions for mild steel immersed in distilled water at pH 8.5.
Figure 3.4: pH vs. time plot in absence and presence of varying concentration
of Cu ions for mild steel immersed in artificial seawater at pH 8.2.
99
Figure 3.5: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 304L immersed in distilled water at pH 4.0.
Figure 3.6: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 304L immersed in distilled water at pH 6.5.
100
Figure 3.7: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 304L immersed in distilled water at pH 8.5.
Figure 3.8: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 304L immersed in artificial seawater at pH 8.2.
101
Figure 3.9: pH vs. time plot in absence and presence of varying concentration
of Cu ions for SS 316L immersed in distilled water at pH 4.0.
Figure 3.10: pH vs. time plot in absence and presence of varying concentration
of Cu ions for SS 316L immersed in distilled water at pH 6.5.
102
Figure 3.11: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 316L immersed in distilled water at pH 8.5.
Figure 3.12: pH vs. time plot in absence and presence of varying concentration of Cu ions for SS 316L immersed in artificial seawater at pH 8.2.
103
Figure 3.13: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for mild steel immersed in distilled water at pH 4.0
Figure 3.14: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for mild steel immersed in distilled water at pH 6.5
104
Figure 3.15: Ecorr vs. time plot in absence and presence of varying concentration
of Cu ions for mild steel immersed in distilled water at pH 8.5.
Figure 3.16: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for mild steel immersed in artificial seawater at pH 8.2.
105
Figure 3.17: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 304 L immersed in distilled water at pH 4.0.
Figure 3.18: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 304 L immersed in distilled water at pH 6.5.
106
Figure 3.19: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 304 L immersed in distilled water at pH 8.5.
Figure 3.20: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 304 L immersed in artificial seawater at pH 8.2.
107
Figure 3.21: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 316 L immersed in distilled water at pH 4.0.
Figure 3.22: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 316 L immersed in distilled water at pH 6.5.
108
Figure 3.23: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 316 L immersed in distilled water at pH 8.5.
Figure 3.24: Ecorr vs. time plot in absence and presence of varying concentration of Cu ions for SS 316 L immersed in artificial seawater at pH 8.2.
109
Figure 3.25: Potentiodynamic polarization curves for mild steel in distilled
water (pH=4.0) in absence and presence of Cu (a) Blank (b)1ppm
Cu (c) 100ppm Cu
Figure 3.26: Potentiodynamic polarization curves for mild steel in distilled
water (pH=6.5) in absence and presence of Cu (a) Blank (b)1ppm
Cu (c) 100ppm Cu
110
Figure 3.27: Potentiodynamic polarization curves for mild steel in distilled water
(pH=8.5) in absence and presence of Cu (a) Blank (b)1ppm Cu (c)
100ppm Cu
Figure 3.28: Potentiodynamic polarization curves for mild steel in artificial
seawater (pH=8.2) in absence and presence of Cu (a) Blank
(b)1ppm Cu (c) 100ppm Cu
111
Figure 3.29: Potentiodynamic polarization curves for SS 304L steel in distilled
water (pH=4.0) in absence and presence of Cu (a) Blank (b)1ppm
Cu (c) 100ppm Cu
Fig 3.30: Potentiodynamic polarization curves for SS 304Lsteel in distilled water
(pH=6.5) in absence and presence of Cu (a) Blank (b)1ppm Cu (c)
100ppm Cu
112
Figure 3.31: Potentiodynamic polarization curves for SS 304L in distilled water
(pH=8.5) in absence and presence of Cu (a) Blank (b)1ppm Cu (c)
100ppm Cu
113
(a) (b)
(c)
114
(d)
(e)
Figure 3.32: SEM micrographs of (a) polished mild steel (b) mild steel immersed in distilled water at pH 6.5 (c) mild steel immersed in distilled water containing 100ppm Cu at pH 6.5 (d) mild steel immersed in artificial seawater at pH 8.2 (e) mild steel immersed in artificial seawater containing 100ppm Cu at pH 8.2.
115
(a)
(b)
Figure 3.33: EDAX analysis of (a) mild steel immersed in distilled water at pH 6.5 (b) mild steel immersed in distilled water containing 100ppm