CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

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Chapter 3 rate of 10Å/min using 5 keV Ar + ion beam with current of 50 µA/cm 2 at an incidence angle of 45°, and at a pressure of 1×10 -5 Pa. The pressure in the analyzer chamber was of the order 1×10 -7 Pa throughout the measurement. 3.1.5 Electrochemical corrosion studies 3.1.5.1 Open circuit potential vs. time measurement Out of several electrochemical techniques used for the investigation of corrosion, open circuit potential (OCP) measurement over time of immersion is successfully employed over the years for understanding the corrosion process by analyzing the natural fluctuation of the corrosion potential. When a specimen is immersed in corrosive solution both oxidation and reduction reaction takes place, and in general specimen oxidizes and the solution reduces. Thus, open circuit potential or free corrosion potential is defined as the potential of a working electrode in steady state measured with respect to a reference electrode in absence of any perturbation to the working electrode surface [93]. The magnitude of open circuit potential is dependent on the metal/alloy itself, composition of the solution, temperature, and hydrodynamics of the electrolyte. OCP-time measurement provides insight into the instantaneous electrochemical process occurring in the electrode surface, and is important for determining tendency of materials to free corrosion [94]. Moreover, variation in OCP is an indication of the protective power of the passive film building on the surface, and its stability from surface electro-chemical phenomenon occurring in a corrosive environment as a function of time. The change in potential in the anodic direction is termed as noble potential, and indicates the presence of stable passive film whereas the shift of potential in the cathodic direction i.e. active direction indicates the onset of corrosion process. Apart from this, it provides the idea regarding the transient steps in the passive film formation from the signals spontaneously generated from the corroding surface. However, the OCP measurement gives only qualitative information of the corrosion behaviour, and is limited
Chapter 3 regarding kinetics and mechanism of the electrochemical reaction occurring on the surface of an electrode in contact with corrosive reagent. In the present investigations open circuit potential vs. time measurements were carried out using a standard electrochemical cell as shown in Fig. 2.8 [93] in different concentration of nitric acid for unimplanted, nitrogen ion implanted, uncoated, titanium (Ti), titanium dioxide (TiO 2 ), and duplex Ti-TiO 2 coated 304L SS. Fig. 3.8: Schematic of an electrochemical cell for corrosion study [93]. The electrochemical cell comprises of specimen as working electrode, platinised platinum counter electrode and Ag/AgCl reference electrode. The OCP was measured by potentiometric circuit with negligible current generation until the potential remained stable over a reasonable time period. The specimens analyzed are unimplanted, and nitrogen ion implanted 304L SS with
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2.3 Effect of alloying elements on
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4 C H A P T E R 4 73 # $%&' 4.1 In
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6.2.3.2 Open circuit potential vs.
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eprocessing can be recovered, and c
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The ex-situ study of passive film w
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Fig.3.10: Schematic of electrical e
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Fig.6.11: Polarization study of unc
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AISI: American Institute of Steel I
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Chapter 1 C H A P T E R 1 Spent Nuc
Page 26 and 27: Chapter 1 1.3 Challenges in spent n
Page 28 and 29: Chapter 1 corrosion resistance. The
Page 30 and 31: Chapter 1 choice of zirconium is du
Page 32 and 33: C H A P T E R2
Page 34 and 35: Chapter 2 temperature, (c) higher i
Page 36 and 37: Chapter 2 Chromium in excess of 12
Page 38 and 39: Chapter 2 2. 3 Effect of alloying e
Page 40 and 41: Chapter 2 The twins are identified
Page 42 and 43: Chapter 2 and at temperature around
Page 44 and 45: Chapter 2 of adsorption of oxygen o
Page 46 and 47: Chapter 2 transpassive dissolution
Page 48 and 49: Chapter 2 healing chromium oxide fi
Page 50 and 51: Chapter 2 their segregation to the
Page 52 and 53: Chapter 2 is intimately related to
Page 54 and 55: Chapter 2 in nature because the dis
Page 58 and 59: Chapter 3 3.1.1.2 Specimen preparat
Page 60 and 61: Chapter 3 ionized. However, differe
Page 62 and 63: Chapter 3 various industrial applic
Page 64 and 65: Chapter 3 In the present investigat
Page 66 and 67: Chapter 3 3.1.3.2 Atomic force micr
Page 68 and 69: Chapter 3 present on the surface fo
Page 70 and 71: Chapter 3 necessary condition is th
Page 72 and 73: Chapter 3 Y m is the sputter yield.
Page 74 and 75: Chapter 3 Fig. 3.7: Schematic of X-
Page 78 and 79: Chapter 3 different doses of nitrog
Page 80 and 81: Chapter 3 The modulus of electroche
Page 82 and 83: Chapter 3 equivalent circuit as sho
Page 84 and 85: Chapter 3 reference electrode with
Page 86 and 87: Chapter 3 for understanding the pas
Page 90 and 91: Chapter 4 encountered by all materi
Page 92 and 93: Chapter 4 pitting, and intergranula
Page 94 and 95: Chapter 4 The ridged structure, and
Page 96 and 97: Chapter 4 nitric acid is that the b
Page 98 and 99: Chapter 4 Potential (V) Vs Ag/AgCl
Page 100 and 101: Chapter 4 4.2.3 In-situ electrochem
Page 102 and 103: Chapter 4 The surface morphologies
Page 104 and 105: Chapter 4 a b c d Opening up of gra
Page 106 and 107: Chapter 4 Intensity (Arbitrary unit
Page 108 and 109: Chapter 4 The chromium, and oxygen
Page 110 and 111: Chapter 4 Intensity (Arbitrary unit
Page 114 and 115: Chapter 5 elements, and often impar
Page 116 and 117: Chapter 5 5.2 Results and discussi
Page 118 and 119: Chapter 5 Presence of oxygen is due
Page 120 and 121: Chapter 5 was an increase in marten
Page 122 and 123: Chapter 5 formation of Cr 2 N was a
Page 124 and 125: Chapter 5 electrochemical environme
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Chapter 5 N + Dose E corr (mV vs. A
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Chapter 5 layer capacitance (C dl )
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Chapter 5 correlation between surfa
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Chapter 5 boundary dissolution was
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Chapter 6 C H A P T E R 6
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Chapter 6 193]. As a single phase c
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Chapter 6 particles range from 8×1
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Chapter 6 Results revealed that in
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Chapter 6 The change over from capa
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Chapter 6 The impedance parameters
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Chapter 6 Conc. Substrate condition
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Chapter 6 6.6a-d. The uncoated spec
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Chapter 6 (55.18°) respectively, w
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Chapter 6 OCP shifted in noble dire
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Chapter 6 The high phase angle over
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Chapter 6 Fig. 6.10d: Log f vs. Log
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Chapter 6 Fig. 6.11b: Polarization
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Chapter 6 Covalent aspect of lattic
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Chapter 6 As compared to uncoated s
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Chapter 6 6.2.3.2 Open circuit pote
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Chapter 6 Similarly, the plots for
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Chapter 6 for the duplex coating, a
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Chapter 6 Fig.6.16b: Polarization s
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Chapter 6 6.2.3.5 Morphological exa
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Chapter 7 C H A P T E R 7 The cha
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Chapter 7 1. Surface morphology exa
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Chapter 7 6 Duplex Ti-TiO 2 coated
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Chapter 7 EC-SPM study on effect
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[1] Baldev Raj, U. Kamachi Mudali,
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[37] G. Okamoto, T. Shibata, Corros
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[79] M. Moens, M. Van Craen, F.C. A
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[117] R.E.Williford, C.F.Windisch J
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[157] N. Mottu, M. Vayer, R. Erre,
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[197] M. Metikos Hukovic, M. Ceraj
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[19] H. H. Uhlig, Corros Sci, 19 (1
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[57] J. F. Ziegler, J. P. Biersack,
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[97] I. Betova, M. Bojinov, V. Kara
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[139] V. Ashworth, R. P. M. Procter
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[176] G. Frankel, G. Grundmeier, H.
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List of publications 1. Referred
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CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

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