ORIGINAL PAPER
K. Suresh Kumar Danadurai á T.M. Sridhar
S.V. Narasimhan á S. Rajeswari
Surface characterisation and crevice corrosion behaviourof nickel-based alloys in the paper industry
Received: 22 February 1999 / Accepted: 6 June 1999
Abstract Recycled water in the paper industry acts as astronger electrolyte as its concentration and temperatureare quite high. The 帮写英语论文lower pH that exists in these solu-tions enhances the corrosion and the high concentrationof solids leads to leaching of metal ions from surface.Crevice corrosion is a form of localised attack, whichcan quickly induce metal perforation even with highgrade stainless steels like 316L when the protectivechromium oxide ®lm is damaged. A specially designedcrevice cell assembly was used to study the electro-chemical www.51lunwen.org 无忧论文网提供毕业论文，硕士论文，英语论文，博士论文 www.51lunwen.org qq1422600067
aspects of nickel-based alloys with the com-monly used 316L SS. The mounted specimen with itsmedium, which is normally encountered in the papermachine section. The nickel-based alloys show remark-able crevice corrosion resistance. X-ray photoelectronspectroscopy studies revealed that the enhanced corro-sion resistance of these alloys is due to the contributingnature of the individual elements Cr, Ni and Mo andtheir presence in the form of various oxidised species onthe passive ®lms.
Key words Nickel-based alloys á Crevice corrosion áWhite water á Passive ®lms á X-ray photoelectron
spectroscopy
Introduction
Corrosion problems in the pulp and paper industrieshave caused huge losses in terms of repair and replace-ment. Proper selection of material of construction is veryimportant and serious considerations have to be given inselecting the materials [1]. Crevice corrosion has beenobserved on a variety of passive ®lm-forming metalsexposed to a number of di€erent environments rangingfrom high purity water to the human body [2]. Crevicecorrosion is considered by many to be the most delete-rious form of corrosion as it occurs on the shielded areasof a metal surface where it is dicult to examine theunderlying metal visually and hence results in unpre-dicted catastrophic failures [3]. It is the intense localisedattack frequency that occurs within crevices or other
shielded areas, associated with small volumes of stag-nant solution caused by holes, gasket surfaces lap joints,surface deposits and crevices under holes. The corrosionat the wet metal interface is in¯uenced by a number offactors like the composition of the backwater, surfacemetal and stagnation time. Crevice corrosion is one of
the most detrimental forms for stainless steel corrosionin a white water medium [4].
Chloride ions are the most aggressive anions com-monly present in a white water system, which replacesthe oxygen associated with the passive surface [5]. Theconcentration of chloride present in white water is also
important and varies considerably, depending upon thelocation of the environment. The practice of closure ofthe white water system [6, 7] and closed loop operationconditions promotes the accumulation of chloride ionsin the suction press roll section and headbox section of
the paper mills to alarming proportions, which leads todepletion of oxygen or a reduction in pH within thecorroding crevice. Hence, the present study was under-taken to evaluate the crevice corrosion resistance of thenickel-based alloys along with the reference type 316Lstainless steel. The nature and composition of the pas-sive ®lms formed on the alloys, which contributed to theenhanced corrosion resistance, were analysed by X-rayphotoelectron spectroscopy (XPS).
J Solid State Electrochem (2000) 4: 159±167 Ó Springer-Verlag 2000
K. Suresh Kumar Danadurai á T.M. Sridhar á S. Rajeswari (&)
Department of Analytical Chemistry,
University of Madras, Guindy Campus,
Chennai ± 600 025, India
e-mail: [email protected]
S.V. Narasimhan
Water and Steam Chemistry Laboratory,
BARC Facilities, Kalpakkam ± 603 102, India
E
