Alumina corrosion current

CMP potentiodynamic measurements. Their work showed a large decrease in the corrosion current at 1 wt % of the oxidizer concentration, indicating the formation of a passivating film. AES measurements confirmed the formation of a high oxygen content film with a thickness of 1.5 nm. The addition of 3 wt % alumina to the slurry showed a twofold increase in the removal of copper when compared to the abrasive-free systems. The material removal rate peaked when using 2 wt % oxidizer. 

Hydrolysis is a significant threat to phosphate ester stabiHty as moisture tends to cause reversion first to a monoacid of the phosphate ester ia an autocatalytic reaction. In turn, the fluid acidity can lead to corrosion, fluid gelation, and clogged filters. Moisture control and filtration with Fuller s earth, activated alumina, and ion-exchange resias are commonly used to minimise hydrolysis. Toxicity questions have been minimised ia current fluids by avoiding triorthocresyl phosphate which was present ia earlier natural fluids (38). 

Ni0-NiFe204-Cu cermet material, and of tin oxide anode material, is that of Xiao and coworkers [102], Figure 31 is taken from their work and shows the corrosion rate of the former material at cell current/temperature as a function of alumina content. The densities of these materials were 6.0-6.3 g cm-3. Consequently a corrosion rate of... 

These processes essentially indude the Alkar technology, industrialized in 1958 by UOP, which displays the special feature of being able to use cracked gases with a low ethylene content (8 to 10 per cent volume), and another of using bantu trifluoride deposited on alumina as the catalyst system, thus minimizing corrosion. It currently accounts for nearly 1 million t/year of capacity. 

A cell for the Hall—H roult process is shown in Fig. 4.1, and a block diagram of the whole process is shown in Fig. 4.2. Cell design is determined largely by the need to contain molten cryolite at high temperatures and to withstand attack by molten aluminium and also by sodium and fluorine formed as minor products at the cathode and anode respectively. Hence the cell is a strong steel box lined first with alumina to act as a refractory, thermal insulator and then with carbon. In fact the base of the tank is lined with prebaked carbon blocks which are inlaid with steel bars to reduce their electrical resistance and which act as current carriers to the molten aluminium cathode. The sides are lined with partially graphitized anthracite in coal tar pitch. The process is then run so that there remains a layer of solid cryolite and alumina at the sides of the cell and a soHd crust on the surface. This acts as a further barrier to corrosion and also to reduce the heat loss from the cell. The cell also has facilities for the periodic addition of alumina through the crust and for the removal of aluminium metal by suction. It is hooded with an extractor... 

The interest in the uptake of phosphate by metal oxides such as iron, alumina, and titania arises from current problems found in the study of soils, corrosion, and biomimetic materials. Phosphate reactions with iron and aluminum oxides and hydroxides have been extensively studied by soil chemists because these soil conq)onents are the most abundant of the naturally occurring metal oxides (7, 2) and are the inorganic soil constituents primarily responsible for phosphate reactions in... 

Evolution of (a) the mean coefficient of friction and (b) current of an AISI 316L SS disc (20 mm diameter and 6 mm height) after subjecting it to corrosion wear against an alumina ball (6 mm 0) in an acetate buffer.The AljOj nanoparticles (150 nm) were added as a 20 vol.% suspension (1 1 mixture of deionized water and acetate buffer) (conditions -0.5V/MSE load 6N frequency 2 Hz configuration standard ball-on-flat) alumina ball-on-316L flat) (Radice, 2006). 

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