Cathodic cleaning

Many platiag plants use electrocleaners both anodicaHy and cathodicaHy through the use of reversing switches or ia two separate tanks. Not all anionic surfactants do well ia cathodic cleaning. Proprietary electrocleaners are commonly used and highly recommended. 

SERS due to pyridine on Au electrode surfaces appears to arise from the adsorption of pyridine in or on surface carbon present after the oxidation-reduction cycle [25,26], Anodically roughened Ag electrode surfaces, which were subsequently cathodically cleaned, exhibited no SERS from pyridine. This confirms that the SERS-active phase is carbon-pyridine and not pyridine alone. In ultrahigh vacuum, SERS can be induced in pyridine by coadsorbing pyridine with CO [27], The effect depends on the type of silver surface and involves shifts in the peak positions and intensities of some of the vibrational modes. SERS peaks were not observed at 2100 cm 1 at the position of the C O stretching mode of CO. A possible interpretation is that surface complexes are formed between pyridine and CO molecules at the active or hot sites on the silver surface. 

Reisse and co-workers [147-149] were the first to describe a novel device for the production of metal powders using pulsed sonoelectrochemical reduction. This device exposes only the flat circular area at the end of the sonic tip to the electrodeposition solution. The exposed area acts as both cathode and ultrasound emitter, named by Reisse et al. as sonoelectrode . A pulse of electric current produces a high density of fine metal nuclei. This is immediately followed by a burst of ultrasonic energy that removes the metal particles from the cathode, cleans the surface of the cathode, and replenishes the double layer with metal cations by stirring the solution. In [145], a list is given of chemically pure fine crystalline powders, mostly metals or metallic alloys, prepared by this method, with particle sizes varying between 10 and 1000 run depending on deposition conditions. 

The cleaning and activation potentials E5 and E6 originate from the quadruple-potential waveform, which was introduced for the detection of carbohydrates with improved long-term reproducibility [20], This approach utilizes a cathodic cleaning of the electrode at —2V (E5) and activation of the catalytic surface via transient oxide formation at -1-0.6 V. The potential is then returned to the initial value of —0.2 V for the piupose of reducing the gold oxide. 

Cathodic cleaning of high-strength steels in either acid or alkaline baths should be avoided, anodic cleaning is permissible. 

Cathodic cleaning Cleaning in an electrolytic cell where the surface to be cleaned is the cathode. See also Anodic cleaning. 

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