CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

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Chapter 1 choice of zirconium is due to its high corrosion resistance as compared to titanium and austenitic stainless steel with or without the presence of oxidizing species. As compared to austenitic stainless steel, zirconium does not undergo intergranular corrosion, and compared to titanium it does not suffer from vapour and condensate phase corrosion problems in boiling nitric acid. Comparative analysis on the corrosion resistance of 20 Cr-20 Ni austenitic stainless steel, Ti, and Zr in 17-70 % nitric acid concentration in boiling condition in presence of hexavalent chromium (Cr 6+ ) showed high corrosion resistance for zirconium as compared to others [29]. The high corrosion resistance is attributed to natural formation of dense, stable and self healing zirconium oxide (ZrO 2 ) film on the surface which protects the material from corrosive environments [1]. Moreover, it does not form non-adherent oxide with poor corrosion resistance under condensing condition as seen in case of titanium. Recent corrosion study [30] on zirconium, and its welds showed superior corrosion resistance as compared to other candidate material like Ti, Ti-5% Ta, and Ti- 5% Ta-1.8 % Nb. No corrosion attack was observed in liquid, vapor and condensate zones of boiling 11.5 M nitric acid. Due to high corrosion resistance, inspection, and maintenance is also a less concern for zirconium. Even though, zirconium shows outstanding corrosion resistance in nitric acid medium, certain factors require thorough investigation, such as fluoride content in the process medium and stress corrosion cracking. The presence of fluoride ions as complexing agent is detrimental to passive film stability, and increases the dissolution rate of the material even at low concentration of fluoride ion [31]. However, the effect of fluoride ion can be reduced by adding corrosion inhibitor such as zirconium sponge and zirconium nitrate to convert to non-corrosive compound. Stress corrosion cracking (SCC), can occur in Zr exposed to hot boiling nitric acid (> 70 %) [29]. Particularly, heat effected zones of zirconium welds are considered to be sensitive to SCC. However, recent study shows that zirconium has excellent corrosion resistance, and do not show
Chapter 1 susceptibility to SCC in simulated dissolver solution carried out in small-scale mock-up test even after 7 yrs [32]. However, unlike austenitic stainless steel, large scale application of zirconium is restricted to demanding conditions only, because it is seven times expensive and fabrication cost is five times more compared to conventional 304L austenitic stainless steel.
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Page 12 and 13: 6.2.3.2 Open circuit potential vs.
Page 14 and 15: eprocessing can be recovered, and c
Page 16 and 17: The ex-situ study of passive film w
Page 18 and 19: Fig.3.10: Schematic of electrical e
Page 20 and 21: Fig.6.11: Polarization study of unc
Page 22 and 23: AISI: American Institute of Steel I
Page 24 and 25: 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 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 56 and 57: C H A P T E R3
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 76 and 77: Chapter 3 rate of 10Å/min using 5
Page 78 and 79: 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
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Chapter 3 reference electrode with
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Chapter 3 for understanding the pas
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C H A P T E R4
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Chapter 4 encountered by all materi
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Chapter 4 pitting, and intergranula
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Chapter 4 The ridged structure, and
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Chapter 4 nitric acid is that the b
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Chapter 4 Potential (V) Vs Ag/AgCl
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Chapter 4 4.2.3 In-situ electrochem
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Chapter 4 The surface morphologies
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Chapter 4 a b c d Opening up of gra
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Chapter 4 Intensity (Arbitrary unit
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Chapter 4 The chromium, and oxygen
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Chapter 4 Intensity (Arbitrary unit
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C H A P T E R5
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Chapter 5 elements, and often impar
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Chapter 5 5.2 Results and discussi
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Chapter 5 Presence of oxygen is due
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Chapter 5 was an increase in marten
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Chapter 5 formation of Cr 2 N was a
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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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