（節(jié)選）外文翻譯--再生水處理過(guò)程中不銹鋼輸水管道腐蝕垢特征研究（原文）

1、Characterization of corrosion scale formed on stainless steel delivery pipe for reclaimed water treatmentYong Cui a, Shuming Liu a, *, Kate Smith a, Kanghua Yu a, Hongying Hu a, Wei Jiang b, Yuhong Li ba School of Enviro

2、nment, Tsinghua University, 100084, Beijing, China b Tianjin Water Recycling Company Limited, 300381, Tianjin, Chinaa r t i c l e i n f oArticle history:Received 23 May 2015Received in revised form2 November 2015Accepted

3、 7 November 2015Available online 12 November 2015Keywords:Reclaimed waterStainless steelLocalized corrosionCorrosion scalePodiform chromite depositWater quality parametersa b s t r a c tTo reveal corrosion behavior of st

4、ainless steel delivery pipe used in reclaimed water treatment, thisresearch focused on the morphological, mineralogical and chemical characteristics of stainless steelcorrosion scale and corroded passive film. Corrosion

5、scale and coupon samples were taken from a type304 pipe delivering reclaimed water to a clear well in service for more than 12 years. Stainless steelcorrosion scales and four representative pipe coupons were investigated

6、 using mineralogy and materialscience research methods. The results showed corrosion scale was predominantly composed of goethite,lepidocrocite, hematite, magnetite, ferrous oxide, siderite, chrome green and chromite, th

7、e same as thatof corroded pipe coupons. Hence, corrosion scale can be identified as podiform chromite deposit. The lossof chromium in passive film is a critical phenomenon when stainless steel passive film is damaged byl

8、ocalized corrosion. This may provide key insights toward improving a better comprehension of theformation of stainless steel corrosion scale and the process of localized corrosion. The localized corrosionbehavior of stai

9、nless steel is directly connected with reclaimed water quality parameters such as residualchlorine, DO, Cl? and SO4 2?. In particular, when a certain amount of residual chlorine in reclaimed water ispresent as an oxidant

10、, ferric iron is the main chemical state of iron minerals.© 2015 Elsevier Ltd. All rights reserved.1. IntroductionStainless steels are widely applied to processes for producing reclaimed water in water treatment pla

11、nts throughout the world. They are used in diverse applications, such as delivery pipes, valves and water treatment equipment due to their corrosion resistance and durability (Ryan et al., 2002). Iron alloys contain a mi

12、nimum of approximately 11% chromium which prevents the formation of rust in aqueous conditions (Sedriks,1979). In general, AISI type 304 steel is the most commonly used austenitic stainless steel. It is commonly produced

13、 by standard cutting and turning processes for a cost-effective solution. These processes can cause strain-induced martensite to form at the machined surface of stainless steel, and improve their corrosion resistance (Ma

14、rtin et al., 2011). Although stainless steels have extremely good corrosion resistance, which is provided by a very thin surface FeeCr alloy oxide film, they can benevertheless susceptible to major modes of corrosion, in

15、cluding pitting corrosion, crevice corrosion, intergranular corrosion and stress corrosion cracking (Frankel, 1998; Hu et al., 2011; Laitinen, 2000; Lott and Alkire, 1989; Punckt et al., 2004; Zhang et al., 2015). When s

16、tainless steels are used in aggressive aqueous envi- ronments, pitting and crevice corrosion of stainless steels caused by chloride ions are common phenomena (Laitinen, 2000; Tian et al., 2014). Passive film is damaged a

17、nd corrosion products form on the surface of iron alloy by electrochemical corrosion and oxidation reactions in the processes of pitting and crevice corrosion (Olsson and Landolt, 2001). Massive corrosion scales have occ

18、urred as a result of long-term accumulation of corrosion products. These lead to the failure of stainless steels, problems with equipment, water contamination and increased pumping costs (Sander et al., 1996). It is a cr

19、ucial issue for water utilities. Inter-granular corrosion and stress corrosion cracking are serious problems for 304 stainless steels. These forms of corrosion are due to grain boundary sensi- tization when the material

20、is exposed to nitric acid fluid or high temperature. The exposure results in the precipitation of chromium carbides at the grain boundary and the formation of chromium * Corresponding author.E-mail address: shumingliu@ts

21、inghua.edu.cn (S. Liu).Contents lists available at ScienceDirectWater Researchjournal homepage: www.elsevier.com/locate/watreshttp://dx.doi.org/10.1016/j.watres.2015.11.0210043-1354/© 2015 Elsevier Ltd. All rights r

22、eserved.Water Research 88 (2016) 816e825size was 0.02?and each step was separated by a 0.5 s count time. Stainless steel coupons were measured in continuous-scan with the 2q range of 10e90?. Step size was 0.02? at scanni

23、ng speed 8? per 2q min?1. The Jade 5.0 software was used to retrieve information on the crystalline phase.2.5. Raman spectroscopy (RMS)Information about molecular vibrations of scale powders and pipe coupons was obtained

24、 using a laser micro-Raman spectros- copy (Renishaw inVia, Britain) with a CCD detector, coupled to a microscope. The samples were excited with a 25 mW argon-ion 532 nm laser light and the spectrum acquisition time was 3

25、0 s (Cano et al., 2014). A 100? lens was employed to focus the laser on the samples and to capture the diffusion light. The Raman spectra of the stainless steel corrosion scale and pipe coupon were in the range of 100e12

26、00 cm?1 band for wavelengths. The RMS is cali- brated by a pure alumina silicon wafer.2.6. X-ray photoelectron spectroscopy (XPS)The chemical states analysis of scales and coupons were carried out using XPS (Thermo ESCAL

27、AB 250xi, Britain) with Al-Ka X-ra- diation source. The vacuum in the analysis chamber was 3.4 ? 10?6 Pa. The sputtering area of samples was 2 ? 2 mm under conditions of 3 kV and 2 mA. After a survey spectrum of samples

28、was scanned, the high-resolution energy spectra of C 1s, O 1s, Fe 2p, Cr 2p and Ni 2p were recorded. Thermo Avantange software was used to collect and treat all experimental data. XPS Peak 4.1 software was used to analyz

29、e and fit samples data.2.7. X-ray fluorescence spectrometer (XRF)The major elemental composition of corrosion scales and pipe coupons was measured using an X-Ray Fluorescence Spectrometer (Shimadzu XRF-1800 SEQUENTIAL, J

30、apan). The percent concentra- tion (by weight) of elemental composition was presented on the basis of the protocol (Gerke et al., 2010).3. Results and discussion3.1. Microstructures of stainless steel pipe couponsThe mic

31、rostructures electrochemically etched in Practice A, A262, ASTM, are shown in Fig. 1. The polished surface of stainless steel specimen has no grain boundary (Fig. 1(a)). The sample of non-sensitized stainless steel is pr

32、esented in the ‘step’ micro- structure (steps between grains, no ditches at grain boundaries) in Fig. 1(b). The sample of sensitized stainless steel was similar to ‘dual’ microstructure (some ditches at grain boundaries

33、in addition to steps, but no one grain completely surrounded) as shown in Fig. 1(c). These tested results indicate the 304 stainless steel pipe has a very low degree of sensitization. It also confirms the 304 stainless s

34、teel may not be susceptible to inter-granular corrosion (Arutunow et al., 2011; Jian et al., 2013).3.2. Morphology of stainless steel corrosion scales and pipe couponsRepresentative corrosion scales and pipe coupons obta

35、ined from the stainless steel delivery pipeline was shown in Fig. 2. The podiform corrosion scales had formed in the chlorinated reclaimed water and were distributed non-uniformly on the stainless steel pipeline (Fig. 2(

36、a)). They were easily taken down from the innerFig. 1. Optical photomicrographs showing electrochemically etched microstructures of stainless steel pipe coupons: (a) polished surface specimen, (b) non-sensitizedspecimen,

37、 (c) sensitized specimen.Table 1Average water quality parameters and reclaimed water treatment processes.Parameters Water source Reclaimed water Water treatment processpH 7.12 7.15 PrechlorinationTDS 1069 mg/L 807 mg/L C

38、oagulationTotal nitrogen 17.4 mg/L 12.4 mg/L SedimentationTotal phosphorus 0.28 (mg/L as P) 0.13 (mg/L as P) Continuous microfiltrationHardness 338.6 (mg/L as CaCO3) 259.8 (mg/L as P) Reverse osmosis (RO)Alkalinity 195.1

39、 (mg/L as CaCO3) 140.6 (mg/L as P) OzonationCODCr 26.5 mg/L 13.2 mg/L DisinfectionDO 4.89 mg/L 7.59 mg/LNH3? N 5.82 mg/L 3.8 mg/LCl? 261.1 mg/L 195.4 mg/LSO4 2? 234.2 mg/L 190.2 mg/LSiO2 8.38 mg/L 6.5 mg/LFe 0.09 mg/L 0.