Etching with acids

Etching with Acids. Acid etching would be applied usually on a small scale, with limited amounts of acid on restricted areas. 

Parrott et al. (PI9) impregnated alite pastes with a resin, and prepared polished surfaces which were etched with acid to dissolve the cement paste before examination by SEM. Correlations were found between the areas of... 

Beryllium metal, previously etched with acid, reacts with phthalonitrile to yield beryllium phthalocyanine, the only square planar derivative of beryllium known (10). Both anhydrous beryllium and magnesium phthalocyanines react readily with moisture to form very stable dihydrates. Dehydration may be effected only by sublimation in vacuo. Sidorov has studied the interaction of sublimed layers of beryllium and magnesium phthalocyanines with water, by infrared spectroscopy (825). Some of the absorption bands arising from the phthalocyanine unit shift when water vapor is introduced. This behavior was not noted with other phthalocyanines (see Section VI,A). 

In a dedicated plant, the surface of packing can be conditioned so that it will be wetted by the product it has to handle. A packing that must handle aqueous material, for instance, should be free from grease or oil and may with advantage be slightly etched with acid. As is likely to happen on a multi-purpose plant, the result of processing solvents of different... 

The growth of copper oxides on surfaces etched with acids is proportional to time as expected for oxidation of metals in the gas phase. The PAni-pretreated surface behaves differently. The formation of CuO is proportional to y/1, whereas CU2O decreases exponentially to a minimum of 0.6 nm. From the slope of a CuO thickness versus t plot, the rate constant for the formation of CuO was calculated. 

In a final step, a golden cheramic including aluminum and titanium compounds is deposed on the surface of the pieces to increase their mechanical resistance. The pieces are marked either by etching with acid and cobalt salts or printed with dye before they are packed or included in tools. 

Although changing the chemistry of the surface undoubtedly has a drastic improvement in antibacterial properties, the downstream approval process becomes more cumbersome with each chemical modification. An alternative approach is to change only the physical features of the surface by etching with acid and studying the resultant... 

Dental composite materials are now used that have several advantages over traditional amalgams. The composites can be made in a wide range of colors, for example, to match the color of the other teeth. The existing healthy portion of the tooth can be etched with acid, moreover, to create pores into which the composite material can bond. With traditional dental amalgam, the dentist must create indentations in the healthy tooth to hold the amalgam in place. Destroying a portion of the healthy tooth is undesirable and can be avoided with the use of the composite. 

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