Corrosion is one of the main causes of metal material failure. In corrosion research, it is difficult to obtain accurate information on the corrosion evolution. The development of spatial-resolution technology enables the in-situ observation of metal corrosion processes to be realized. By combining the spatial-resolution technology and electrochemical techniques, more microscopic metal corrosion information can be obtained, which facilitates more accurate acquisition of corrosion information and provides reliable support for the illustration of corrosion mechanism. This paper reviews several classical spatial-resolution techniques in the field of corrosion in terms their working principle, advantages and disadvantages etc. The industrial CCD camera, digital holographic surface imaging technology, X-ray computed tomography, optical microscope, scanning electron microscope, atomic force microscope and transmission electron microscope are introduced. The application status and development prospects of each technology in the field of in-situ monitoring of metal corrosion are discussed. Finally, these spatial-resolution techniques are compared and corresponding recommendations for use are proposed in the review.
ZHAO Pengxiong, WU Wei, DAN Yong. Application of Spatial-resolution Technology for In-situ Monitoring of Metal Corrosion. Journal of Chinese Society for Corrosion and Protection[J], 2020, 40(6): 495-507 DOI:10.11902/1005.4537.2019.120
Fig.2
CCD images (a~c) and DIC analysis (d~f) of Alloy 600 during SCC test in a tetrathionate solution for 630 min (a, d), 830 min (b, e) and 1130 min (c, f)[19]
Fig.4
Holograms and corresponding phase maps of 304 stainless steel electrode during potentiostatic measurement at different times in 0.1 mol·L-1 FeCl3 solution at 0.30 VSCE[23]
Fig.5
Photo of the miniature electrochemical cell with the capability to apply strain to a type 304L stainless steel wire sample in in-situ X-ray tomography experiment (a) and in-situ cell used in X-ray CT experiment (b)[31]
Fig.6
Reconstructed X-ray CT images of the wire sample after the 1st electrochemical polarization scan (a) and the 2nd potentio-dynamic polarization scan (b) and SEM image of the sample with three pits (c)[31]
Fig.8
Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)[40]
Fig.11
AFM topographic maps showing GB corrosion process of sensitised AISI 304 stainless steel in 1%NaCl solution: before (a) and after (b) the formation of intergranular pit, and the full intergranular pit formed (c)[58]
Correlations of electrochemical noise, acoustic emission and complementary monitoring techniques during intergranular stress-corrosion cracking of austenitic stainless steel
An experimental protocol (workflow) has been developed for time-lapse x-ray nanotomography (nano-CT) imaging of environmentally driven morphological changes to materials. Two case studies are presented. First, the leaching of nanoparticle corrosion inhibitor pigment from a polymer coating was followed over 14 days, while in the second case the corrosion damage to an AA2099 aluminium alloy was imaged over 12 hours. The protocol includes several novel aspects relevant to nano-CT with the use of a combination of x-ray absorption and phase contrast data to provide enhanced morphological and composition information, and hence reveal the best information to provide new insights into the changes of different phases over time. For the pigmented polymer coating containing nominally strontium aluminium polyphosphate, the strontium-rich components within the materials are observed to leach extensively whereas the aluminium-rich components are more resistant to dissolution. In the case of AA2099 it is found that the initial grain boundary corrosion is driven by the presence of copper-rich phases and is then followed by the corrosion of grains of specific orientation.
ShiJ J, MingJ, ZhangY M, et al.
Corrosion products and corrosion-induced cracks of low-alloy steel and low-carbon steel in concrete
The corrosion behaviours of the welded joints between steels Cr5Mo andA302 (Cr25Ni13) in the H2S containing solution (NACE TM--01--77standard) were studied. In situ SEM observations revealed that comparedwith other zones thefusion boundary is the worst region for corrosion resistance due to thehydrogen induced disbonding, the corrosion resistance of the post--weldheat--treated jointis worse than that of the as--welded one and the fusion boundary with abroad scale has a stronger resistance for the hydrogen induced disbondingthan the narrow one. These variations are related to the inhomogeneousmicrostructures, carbon diffusion, hydrogen--enrichment and stressconcentration around the fusion boundary.
Practical aspects of electrochemical corrosion measurements during in situ analytical transmission electron microscopy (TEM) of austenitic stainless steel in aqueous media
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.
ZhangB, MaX L.
A review-pitting corrosion initiation investigated by TEM
Correlations of electrochemical noise, acoustic emission and complementary monitoring techniques during intergranular stress-corrosion cracking of austenitic stainless steel
CCD images (a~c) and DIC analysis (d~f) of Alloy 600 during SCC test in a tetrathionate solution for 630 min (a, d), 830 min (b, e) and 1130 min (c, f)<sup>[<xref ref-type="bibr" rid="R19">19</xref>]</sup>Fig.2
CCD images (a~c) and DIC analysis (d~f) of Alloy 600 during SCC test in a tetrathionate solution for 630 min (a, d), 830 min (b, e) and 1130 min (c, f)<sup>[<xref ref-type="bibr" rid="R19">19</xref>]</sup>Fig.2
... [19]CCD images (a~c) and DIC analysis (d~f) of Alloy 600 during SCC test in a tetrathionate solution for 630 min (a, d), 830 min (b, e) and 1130 min (c, f)<sup>[<xref ref-type="bibr" rid="R19">19</xref>]</sup>Fig.2
Holograms and corresponding phase maps of 304 stainless steel electrode during potentiostatic measurement at different times in 0.1 mol·L<sup>-1</sup> FeCl<sub>3</sub> solution at 0.30 V<sub>SCE</sub><sup>[<xref ref-type="bibr" rid="R23">23</xref>]</sup>Fig.4
Holograms and corresponding phase maps of 304 stainless steel electrode during potentiostatic measurement at different times in 0.1 mol·L<sup>-1</sup> FeCl<sub>3</sub> solution at 0.30 V<sub>SCE</sub><sup>[<xref ref-type="bibr" rid="R23">23</xref>]</sup>Fig.4
... [23]Holograms and corresponding phase maps of 304 stainless steel electrode during potentiostatic measurement at different times in 0.1 mol·L<sup>-1</sup> FeCl<sub>3</sub> solution at 0.30 V<sub>SCE</sub><sup>[<xref ref-type="bibr" rid="R23">23</xref>]</sup>Fig.4
... [31]Photo of the miniature electrochemical cell with the capability to apply strain to a type 304L stainless steel wire sample in <i>in</i>-<i>situ</i> X-ray tomography experiment (a) and <i>in</i>-<i>situ</i> cell used in X-ray CT experiment (b)<sup>[<xref ref-type="bibr" rid="R31">31</xref>]</sup>Fig.5
Reconstructed X-ray CT images of the wire sample after the 1st electrochemical polarization scan (a) and the 2nd potentio-dynamic polarization scan (b) and SEM image of the sample with three pits (c)<sup>[<xref ref-type="bibr" rid="R31">31</xref>]</sup>Fig.6
Reconstructed X-ray CT images of the wire sample after the 1st electrochemical polarization scan (a) and the 2nd potentio-dynamic polarization scan (b) and SEM image of the sample with three pits (c)<sup>[<xref ref-type="bibr" rid="R31">31</xref>]</sup>Fig.6
... [31]Reconstructed X-ray CT images of the wire sample after the 1st electrochemical polarization scan (a) and the 2nd potentio-dynamic polarization scan (b) and SEM image of the sample with three pits (c)<sup>[<xref ref-type="bibr" rid="R31">31</xref>]</sup>Fig.6
... [40]Photograph of the optical microscope used for <i>in</i>-<i>situ</i> observation in stress corrosion experiment<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.7
Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
... [40]Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
... [40]Photograph of the optical microscope used for <i>in</i>-<i>situ</i> observation in stress corrosion experiment<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.7
Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
... [40]Optical microscope photos of 7075 aluminum alloy after SCC test for 1 h (a), 10 h (b), 15 h (c), 20 h (d), 23 h (e), 23.8 h (f) and 24.5 h (g) and corresponding stress-strain curve (h)<sup>[<xref ref-type="bibr" rid="R40">40</xref>]</sup>Fig.8
... [58]Partial enlarged drawing of <i>in</i>-<i>situ</i> experimental set-up of HS-AFM and three-electrode system<sup>[<xref ref-type="bibr" rid="R58">58</xref>]</sup>Fig.10
AFM topographic maps showing GB corrosion process of sensitised AISI 304 stainless steel in 1%NaCl solution: before (a) and after (b) the formation of intergranular pit, and the full intergranular pit formed (c)<sup>[<xref ref-type="bibr" rid="R58">58</xref>]</sup>Fig.11
AFM topographic maps showing GB corrosion process of sensitised AISI 304 stainless steel in 1%NaCl solution: before (a) and after (b) the formation of intergranular pit, and the full intergranular pit formed (c)<sup>[<xref ref-type="bibr" rid="R58">58</xref>]</sup>Fig.11
... [58]AFM topographic maps showing GB corrosion process of sensitised AISI 304 stainless steel in 1%NaCl solution: before (a) and after (b) the formation of intergranular pit, and the full intergranular pit formed (c)<sup>[<xref ref-type="bibr" rid="R58">58</xref>]</sup>Fig.11
Practical aspects of electrochemical corrosion measurements during in situ analytical transmission electron microscopy (TEM) of austenitic stainless steel in aqueous media
... [66]Dynamic potential polarization curve of the sample after polarization measurement (a) and STEM images showing corrosion process (b~f)<sup>[<xref ref-type="bibr" rid="R66">66</xref>]</sup>Fig.12
