Electrochemical Blistering

Other processes have been developed in which the impregnation is accompHshed in one or two steps the most promising is electro deposition directiy from nitrate solutions having pH controlled at 4—5. After electro deposition, the plaques are either cathodicaHy polarized in sodium hydroxide solution or electrochemically formed in sodium hydroxide to eliminate all traces of nitrate. The latter steps must proceed at low current densities to avoid blistering and shedding of the loaded plaques. 

Additional detectors currently available use other technologies such as electrochemical detectors for blister, nerve, blood, and choking agents, and infrared spectroscopy detectors or photo ionization detectors for the detection of blister and nerve... 

Some 100 years after Cavendish s discovery of hydrogen, and only 3 years after it was realized that hydrogen sorbed from chemical or electrochemical sources causes blistering and embrittlement to steel vessels, Graham [29] observed the ability of palladium to absorb hydrogen and wrote in Philosophical Transactions of the Royal Society of London ... 

Coated specimens were placed in an electrochemical cell. After 4 hours of temperature, open-circuit potentials were measurements were made on duplicate samples, in a salt spray test cabinet (ASTM B117-73) for 1, 17 and 96 hours respectively and their surfaces photographed in order to calculate the percentage of surface covered by corroded spots and blisters (ASTM D610-68). 

Melting defects must be held to a minimum. Solid inclusions (stones) in the form of refractory particles, unmelted batch, or devitrification, affect the strength as well as optical integrity. Gaseous inclusions (seeds and blisters) caused by improper fining or electrochemical reboil, have the same effect as striae (cords) from improper homogenization. 

Figure 7.1 Electrochemical sensor with (1) plastic spacer, (2) spike for opening ISF-filled blister, (3) ISF, (4.1) working electrode, (4.2) encapsulation of electrical leads, (4.3) reference electrode, (5) connection to vacuum, (6) ISF-filled blister, (7) fluidic pathway, (8.1) stratum comeum, (8.2) epidermis, and (8.3) dermis. Reprinted with permission from Ref. 36. Copyright 2002 Verlag Walter de Gruyter GmbH Co. KG.

The pressurized blister test is an excellent method to combine electrochemical reactions at polymer/metal interfaces with a mechanical load. It allows the application of a mechanical stress from a homogeneously pressurized electrolyte on the adhesive/metal interface in a sample geometry that is accessible for the HR-SKP [28]. Depending on the adjusted conditions, information on the synergy of mechanical stresses, elastic or inelastic deformations of the adhesive, transport processes, and corrosive reactions could be obtained with this method. 

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