CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

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Chapter 6 C H A P T E R 6 ! The chapter deals with the investigation on the corrosion performance of sputter deposited Ti, TiO 2 , and duplex Ti-TiO 2 coated AISI 304L SS in nitric acid medium using electrochemical, and surface morphological studies. The results revealed that, titanium coated 304L SS showed moderate to marginal improvement in corrosion resistance in 1 M, and 8 M nitric acid, respectively. TiO 2 coated 304L SS specimens showed good corrosion resistance in both low (1 M), and high concentration (8 M), however towards higher concentration uniform dissolution of the coated surface was observed. Duplex Ti-TiO 2 coated 304L SS specimens showed improved corrosion resistance as compared to both Ti and TiO 2 coated 304L SS from dilute to concentrated medium. The percentage of protection efficiency for base material increases significantly for duplex Ti-TiO 2 coating as compared to single layer Ti and TiO 2 coatings. 6.1 Introduction Top surface modification using protective coating is the easiest method for improving surface properties as well as corrosion resistance of the base material. The tailoring of the surface properties such as minimizing the surface irregularities and roughness on the surface, impeding the current flow between the microscopic anodic and cathodic regions on the surface, enhancing barrier layer strength thereby improving the passivation property are the essential coating properties which imparts greater resistance to the base material from corrosive environments [172- 175]. Thus, protective coatings are unique, and are most widely used in varying forms in a broad
Chapter 6 range of corrosive environments to increase the performance of engineering materials. Moreover, the basis for wide spread use of coatings as well as development and advancement in coating technology is because of increasing corrosion problems, tighter economic situations, and optimal performance of technologically important materials in various industries. The expanding use of coatings has generated the need to understand the coating-solution interaction in order to access their performance in corrosive environments. The basic approach of corrosion protection using protective coating is to cut-off the interaction between substrate and electrochemical environment by forming barrier over the surface [176-178]. The coating-solution interaction is a complex phenomenon, and involves various factors such as barrier property, topographical features, surface chemistry, and solution chemistry etc. The primary factor responsible for corrosion resistance is the barrier property of the coating which is determined by the lattice energy, bond energy, heat of formation, and band gap etc of the coated material [176,179]. Topographical features have greater influence on the corrosion resistance. The coating topography is largely anisotropic, and the presences of pores, pinholes, flaws on the coated surface are detrimental from corrosion point of view [180,181]. The surface chemistry of coating such as chemical composition of coating has its effect on the electrochemical properties at the coatingsolution interface as well as coating-substrate interface [182,183]. Similarly, the solution composition also has effect on electrochemical corrosion properties such as corrosion potential, passivation tendency and corrosion current from the coated surface etc [184,185]. All the above properties decide the life time of the coating in corrosive medium. Metallic and ceramic coatings with good passivity, low electronic conductance or insulating properties, and good tribological properties are known to protect the metals, and alloys from corrosive environments [186-189]. Titanium (Ti), and titanium dioxide (TiO 2 ) are widely used as coating materials for corrosion protection in a wide range of corrosive environments [190-
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2.3 Effect of alloying elements on
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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
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Chapter 1 1.3 Challenges in spent n
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Chapter 1 corrosion resistance. The
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Chapter 1 choice of zirconium is du
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C H A P T E R2
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Chapter 2 temperature, (c) higher i
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Chapter 2 Chromium in excess of 12
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Chapter 2 2. 3 Effect of alloying e
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Chapter 2 The twins are identified
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Chapter 2 and at temperature around
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Chapter 2 of adsorption of oxygen o
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Chapter 2 transpassive dissolution
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Chapter 2 healing chromium oxide fi
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Chapter 2 their segregation to the
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Chapter 2 is intimately related to
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Chapter 2 in nature because the dis
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C H A P T E R3
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Chapter 3 3.1.1.2 Specimen preparat
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Chapter 3 ionized. However, differe
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Chapter 3 various industrial applic
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Chapter 3 In the present investigat
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Chapter 3 3.1.3.2 Atomic force micr
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Chapter 3 present on the surface fo
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Chapter 3 necessary condition is th
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Chapter 3 Y m is the sputter yield.
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Chapter 3 Fig. 3.7: Schematic of X-
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Chapter 3 rate of 10Å/min using 5
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Chapter 3 different doses of nitrog
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Chapter 3 The modulus of electroche
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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 88 and 89: C H A P T E R4
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 112 and 113: C H A P T E R5
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
Page 126 and 127: Chapter 5 N + Dose E corr (mV vs. A
Page 128 and 129: Chapter 5 layer capacitance (C dl )
Page 130 and 131: Chapter 5 correlation between surfa
Page 132 and 133: Chapter 5 boundary dissolution was
Page 136 and 137: Chapter 6 193]. As a single phase c
Page 138 and 139: Chapter 6 particles range from 8×1
Page 140 and 141: Chapter 6 Results revealed that in
Page 142 and 143: Chapter 6 The change over from capa
Page 144 and 145: Chapter 6 The impedance parameters
Page 146 and 147: Chapter 6 Conc. Substrate condition
Page 148 and 149: Chapter 6 6.6a-d. The uncoated spec
Page 150 and 151: Chapter 6 (55.18°) respectively, w
Page 152 and 153: Chapter 6 OCP shifted in noble dire
Page 154 and 155: Chapter 6 The high phase angle over
Page 156 and 157: Chapter 6 Fig. 6.10d: Log f vs. Log
Page 158 and 159: Chapter 6 Fig. 6.11b: Polarization
Page 160 and 161: Chapter 6 Covalent aspect of lattic
Page 162 and 163: Chapter 6 As compared to uncoated s
Page 164 and 165: Chapter 6 6.2.3.2 Open circuit pote
Page 166 and 167: Chapter 6 Similarly, the plots for
Page 168 and 169: Chapter 6 for the duplex coating, a
Page 170 and 171: Chapter 6 Fig.6.16b: Polarization s
Page 172 and 173: Chapter 6 6.2.3.5 Morphological exa
Page 174 and 175: Chapter 7 C H A P T E R 7 The cha
Page 176 and 177: Chapter 7 1. Surface morphology exa
Page 178 and 179: Chapter 7 6 Duplex Ti-TiO 2 coated
Page 180 and 181: Chapter 7 EC-SPM study on effect
Page 183 and 184: [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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