Studying localized corrosion using liquid cell transmission electron microscopy

Chee, See Wee; Pratt, Sarah Hoppe; Hattar, Khalid Mikhiel; Duquette, D. J.; Ross, Frances M.; Hull, R.

doi:10.1039/c4cc06443g

Cited by 70 publications

(54 citation statements)

References 28 publications

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“…Recent studies have also identified alternative factors that may also affect the liquid during in situ aqueous experiments; these studies have primarily concentrated on the electron beam/liquid interaction such as the reported generation of H 2 bubbles (Grogan et al, 2013). In other studies investigators were primarily concerned with nanoparticles, nanowires, or sputtered thin films located between two SiN x windows, resulting in the creation of partially or fully filled chamber of aqueous solution, all of which differ from the specimens used in this work (de Jonge et al, 2010;Woehl et al, 2012Woehl et al, , 2013Chee et al, 2015;Schilling et al, 2015). In these cases, the volume ratio of nanoparticles and electrolyte is small compared with a conventional bulk electrochemical experimental cell, which is comprised of a larger metal specimen and surrounding electrolyte.…”

Section: In Situ Aqueous Studies: Corrosion Basicsmentioning

confidence: 99%

“…Chee et al (2015) deposited a thin Al layer with Au on an electrochemical SiN x window, to measure the galvanic corrosion in a 0.01 mol NaCl electrolyte. Their study demonstrated that it was possible to measure the electrochemical behavior of the interface between sputtered Al and the electrolyte for pit initiation and galvanic corrosion.…”

Section: In Situ Aqueous Studies: Previous Workmentioning

confidence: 99%

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Practical Aspects of Electrochemical Corrosion Measurements During In Situ Analytical Transmission Electron Microscopy (TEM) of Austenitic Stainless Steel in Aqueous Media

et al. 2017

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The capability to perform liquid in situ transmission electron microscopy (TEM) experiments provides an unprecedented opportunity to examine the real-time processes of physical and chemical/ electrochemical reactions during the interaction between metal surfaces and liquid environments. This work describes the requisite steps to make the technique fully analytical, from sample preparation, through modifications of the electrodes, characterization of electrolytes, and finally to electrochemical corrosion experiments comparing in situ TEM to conventional bulk cell and microcell configurations.

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Section: In Situ Aqueous Studies: Corrosion Basicsmentioning

confidence: 99%

Section: In Situ Aqueous Studies: Previous Workmentioning

confidence: 99%

Practical Aspects of Electrochemical Corrosion Measurements During In Situ Analytical Transmission Electron Microscopy (TEM) of Austenitic Stainless Steel in Aqueous Media

et al. 2017

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“…Metals in contact with aqueous solutions, depending on their surface morphology, undergo different modes of corrosion [2]: general, pitting, crevice, inter-granular, galvanic, and erosion corrosion, environmentally induced fracture, and dealloying. In spite of its importance, many aspects of localized corrosion of metals are not well understood [3], probably because it is often difficult to monitor the corrosion processes at high spatial resolution under a liquid layer. Liquid cell transmission electron microscopy (LC-TEM), coupled with electrochemical control and analytic functions, enables the observation of structural changes and chemical processes in liquid phases.…”

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confidence: 99%

“…Liquid cell transmission electron microscopy (LC-TEM), coupled with electrochemical control and analytic functions, enables the observation of structural changes and chemical processes in liquid phases. It provides a combination of temporal and spatial resolution that is difficult to achieve using other characterization techniques [4], and has yielded detailed information on corrosion kinetics in liquid solutions [3,4].…”

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confidence: 99%

In Situ LC-TEM Studies of Corrosion of Metal Thin Films in Aqueous Solutions

et al. 2015

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Chemical reactions with the environment result in corrosion or degradation of the properties of materials [1]. Metals in contact with aqueous solutions, depending on their surface morphology, undergo different modes of corrosion [2]: general, pitting, crevice, inter-granular, galvanic, and erosion corrosion, environmentally induced fracture, and dealloying. In spite of its importance, many aspects of localized corrosion of metals are not well understood [3], probably because it is often difficult to monitor the corrosion processes at high spatial resolution under a liquid layer. Liquid cell transmission electron microscopy (LC-TEM), coupled with electrochemical control and analytic functions, enables the observation of structural changes and chemical processes in liquid phases. It provides a combination of temporal and spatial resolution that is difficult to achieve using other characterization techniques [4], and has yielded detailed information on corrosion kinetics in liquid solutions [3,4].In this work, we studied corrosion of metal films in aqueous solutions using in situ LC-TEM. We examined general, pitting, and galvanic corrosion in several metals (Au, Al, Ni, Cu, and Zn) under different aqueous solutions. The samples are 20 -50 nm thick metal films deposited by electron beam evaporation over a 50 nm thick silicon nitride membrane of liquid cell window chips. The experiments were carried out in a FEI CM30 TEM, operated at 300 kV, using a continuous flow Hummingbird Scientific LC-TEM holder. Deionized water was first introduced into the liquid cell to completely remove air bubbles inside the cell. Then the liquid, either deionized water or a solution containing HCl, H 2 SO 4 , CuSO 4 , PbSO 4 , NaCl, ZnCl 2 , and ZnSO 4 , was introduced. We used low dose imaging protocol and verified that these solutions can be examined for long periods (many hours) without visible beam effects in the liquid. Figure 1 presents corrosion morphologies of a Ni film in deionized water (pH = 7). This corrosion process took place under a constant electron beam illumination and a flow rate of 5 µl/min. Bright field TEM images showed that dissolution of Ni films occurs via the general corrosion mode in which chemical or electrochemical reactions proceed over the entire exposed surface at approximately the same rate of dissolution. The electron beam accelerates the process, presumably via reactive species created by beam-induced radiolysis of water [5,6]. Figure 2 shows corrosion morphologies of an Au film in 0.1M HCl (pH = 1.26). This corrosion took place during linear sweep voltammetry. Image analysis showed that the corrosion of Au films occurs via dissolution of individual grains.We will describe how measurements of the local dissolution kinetics -morphology, composition, and the etching rate of these metal films as a function of solution composition, pH, and metal thicknessprovide insights into corrosion processes with good spatial and temporal resolutions.

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“…Precise engineering of the final morphology relies on a deep understanding of the reaction pathways involved. Although ex situ microscopies provide critical information, the ability to record the process as it takes place is expected to contribute to a deeper understanding [4]. Liquid cell TEM, especially when coupled with electrochemical control and analytical capabilities, provides the needed tool for measuring structural and chemical changes in liquids [4][5][6].…”

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confidence: 99%

Liquid Cell TEM Studies of Galvanic Displacement Reactions in Aqueous Solutions

Park¹,

Steingart

Deligianni³

et al. 2016

Microsc Microanal

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Galvanic displacement reactions are a versatile approach to achieving sophisticated nanostructure engineering. One key application is the formation of nanopatterned surfaces, such as Ni decorated with Pd nanoparticles, which act as highly catalytic substrates for subsequent electroless deposition [1]. Another application is the formation of magnetic nanoparticles with axial or radial compositional modulation [2] and a variety of applications [3]. Precise engineering of the final morphology relies on a deep understanding of the reaction pathways involved. Although ex situ microscopies provide critical information, the ability to record the process as it takes place is expected to contribute to a deeper understanding [4]. Liquid cell TEM, especially when coupled with electrochemical control and analytical capabilities, provides the needed tool for measuring structural and chemical changes in liquids [4][5][6]. Here, we use in situ liquid cell TEM to examine a model system, galvanic deposition of Pd nanoparticles on Ni in an acidic solution, and extend our materials system toward other metal films.We examined galvanic displacement reactions in samples consisting of 20-50 nm thick Ni films deposited by electron beam evaporation onto a 50 nm thick silicon nitride membrane that makes up one viewing window of the liquid cell. These films were imaged in a FEI CM30 TEM, operated at 300 kV [7], in a continuous flow Hummingbird Scientific LC-TEM holder [8,9]. Deionized water was introduced into the liquid cell to remove air bubbles, after which a solution was introduced containing 0.1M HCl or H2SO4 with ppm levels of PdSO4. We used low dose imaging protocols and verified that the solutions can be examined for long periods (hours) without visible beam effects. We observe two different reactions. At long times, we see corrosion of the Ni film under the beam, presumably due to reactive species produced by radiolysis. Figure 1 presents slow Ni corrosion in deionized water (pH = 7) under irradiation, in an example where PdSO4 is not introduced. This process took place at a flow rate of 5 µl/min and zero voltage applied to the electrode. The electron beam causes dissolution by creating reactive radiolytic species in water, i.e. hydrated electrons and radicals, which convert Ni to ions [5,6,9]. Dissolution appears to take place via the general corrosion mode (Fig. 1a). To obtain quantitative reaction kinetics, the average image brightness was analyzed as a function of irradiation time (Fig. 1b), showing an induction time (Fig. 1c). The second reaction observed is the galvanic displacement reaction itself (Figure 2). Here, nucleation and growth of Pd particles tens of nm in diameter is visible when 0.1M H2SO4 (pH = 1) with ppm levels of PdSO4 is flowed (Fig. 2c). Simultaneously, Ni dissolution takes place. Compared to the reaction without the Pd additive, Ni dissolution is accelerated in the presence of Pd; this is as expected since Ni goes into solution as Pd precipitates (Fig. 2a). In the example shown, preferential dissolution ...

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Studying localized corrosion using liquid cell transmission electron microscopy

Cited by 70 publications

References 28 publications

Practical Aspects of Electrochemical Corrosion Measurements During In Situ Analytical Transmission Electron Microscopy (TEM) of Austenitic Stainless Steel in Aqueous Media

Practical Aspects of Electrochemical Corrosion Measurements During In Situ Analytical Transmission Electron Microscopy (TEM) of Austenitic Stainless Steel in Aqueous Media

In Situ LC-TEM Studies of Corrosion of Metal Thin Films in Aqueous Solutions

Liquid Cell TEM Studies of Galvanic Displacement Reactions in Aqueous Solutions

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