Wire beam electrode

This section aims to provide an overview of major laboratory techniques that can be used in REM-based inhibitor research. Particular focus is on the analysis and understanding of difficulties and limitations in major inhibitor testing methods. Attempts are also made to discuss recently developed techniques such as the scanning probe techniques that have already been used or are expected to be useful, in REM inhibitor research. Non-scanning probe techniques that can be used in localized corrosion inhibition research such as electrochemical noise analysis and the wire beam electrode are also briefly introduced. 

Variously designed weight-loss coupon, electrochemical and surface analytical techniques have been utilized in REM-based corrosion inhibitors and conversion coatings research. In particular, electrochemical techniques including EIS and polarization measurements have been widely used to evaluate corrosion inhibition by REM compounds under various environmental conditions. Relatively less attention has been paid to the evaluation of localized corrosion inhibition by REM-based compounds, probably because of methodological difficulties and complexities in making accurate localized corrosion rate measurements. Recently developed techniques such as the scanning probe techniques, electrochemical noise analysis and the wire beam electrode are expected to be useful tools in further REM inhibitor research. 

Y. J. Tan, Y. Fwu and K. Bhardwaj, Electrochemical evaluation of under-deposit corrosion and its inhibition using the wire beam electrode method , Corros. Sci, 53, 1254(2011). 

Y. J. Tan, Monitoring Localized Corrosion Processes and Estimating Localized Corrosion Rates Using a Wire-Beam Electrode , Corrosion, 54,403 (1998). 

Fig. 1. Schematic diagram of the multimass ion imaging detection system. (1) Pulsed nozzle (2) skimmers (3) molecular beam (4) photolysis laser beam (5) VUV laser beam, which is perpendicular to the plane of this figure (6) ion extraction plate floated on V0 with pulsed voltage variable from 3000 to 4600 V (7) ion extraction plate with voltage Va (8) outer concentric cylindrical electrode (9) inner concentric cylindrical electrode (10) simulation ion trajectory of m/e = 16 (11) simulation ion trajectory of rri/e = 14 (12) simulation ion trajectory of m/e = 12 (13) 30 (im diameter tungsten wire (14) 8 x 10cm metal mesh with voltage V0] (15) sstack multichannel plates and phosphor screen. In the two-dimensional detector, the V-axis is the mass axis, and V-axis (perpendicular to the plane of this figure) is the velocity axis (16) CCD camera.

Nanosensors for electrochemical detection have been made for years using more traditional fabrication methods, e.g., pulled platinum strings and carbon fibers. Carbon fibers can be purchased with diameters in the low /am range. These can subsequently be etched in an Ar beam until conically shaped tips are produced with tip diameters between 100 and 500 nm [61]. Similarly, a platinum wire can be heated and pulled in order to create tips of similar diameters. Thick film electrodes made by screen printing [62] have also been shown to find application as transducer in microchaimel systems [63]. 

Fig. 8. Images of LEI ions and electrons, obtained by taking the LEI signal from a thin rod translated across the front of the normal collecting plate at the indicated high voltages 49). The experiment apparatus is shown in the inset 1 high voltage repelling plate, 2 laser beam, 3 flame reaction zone, 4 burner head, 5 low voltage electrode plate, 6 vertically movable signal pick-off wire...

In the second approach, the required localization of metal dissolution is achieved by other means. Some of them were considered in the previous sections. Here, TEs of several types are used [92-97] (1) An electrode with the shape and dimensions corresponding to the required cavity in the WP (2) a TE in the form of a wire or needle, which penetrates into the WP at the expense of its local anodic dissolution and moves according to a certain program, in order to obtain a given contour and (3) a high-speed jet beam of electrolyte from a micronozzle. 

Figure 5.1 Disassembled view of the spectroelectrochemical cell. (1) Tightening brass cap (threaded inside). (2) Brass ring required to tighten the cell. (3) Working electrode (brass rod with platinum soldered to the base). (4) Auxiliary electrode platinum wire with the tip made flush to the teflon base of the cell. (5) Pseudoreference electrode silver wire, also made flush to the teflon. (6,7) Luer-lock-type injection ports. (8) Cell body, top part aluminium, lower part teflon. (All three electrodes and both filling ports are press fitted into the cell body, so that they can be replaced if needed.) (9) Teflon spacer, determines the pathlength of the cell and masks the reference and counter electrodes from the incident beam. (10) Calcium fluoride window (Wilmad, standard 38.5 x 19.5 x 4mm). (11) Rubber gasket. (12) Hollow brass cell body with threaded inlet and outlet ports (Swagelock) for connection to circulating bath. (13) Two-mirror reflectance accessory (Thermo-SpectraTech FT-30). (14,15) Mirrors.

---