Wet-chemical process

Modifications and improvements to the basic process have been made to reduce the quantity of waste products (21,22) in the wet chemical process, to recover HF, and to economically process low Ta, high Nb containing raw materials (23). Several alternative extraction media have been reported in the hterature. Most, except for tributylphosphate (TBP) (24) and tri- -octylphosphine oxide (TOPO) (25), have never been used in industry. 

The plated-type impurities are most commonly encountered with semiconductor substrates they originate, for example, from wet chemical processing steps. It is apparent from Figure 1 that a precise control of the angle of incidence is an essential feature of TXRF instrumentation. 

Wet chemical processes A gas-cleaning process that uses certain chemicals to ensure the maximum retention of a given pollutant in the cleaning fluid. 

Mitra, P. Maiti, H. S. 2004. A wet-chemical process to form palladium oxide sensitiser layer on thin film zinc oxide based LPG sensor. Sens. Actuators B 97 49-58. 

The zinc salt of 5-nitroisophthalic acid [60580-61-2] [5.49] is produced as an easily dispersible pigment by a wet chemical process from 5-nitroisophthalic acid and zinc oxide [5.180]. It has the following properties ... 

Figure 15.7. Scanning electron micrographs of a Ti02-mica pigment prepared by the wet chemical process.

Polyimide surface modification by a wet chemical process is described. Poly(pyromellitic dianhydride-oxydianiline) (PMDA-ODA) and poly(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) polyimide film surfaces are initially modified with KOH aqueous solution. These modified surfaces are further treated with aqueous HC1 solution to protonate the ionic molecules. Modified surfaces are identified with X-ray photoelectron spectroscopy (XPS), external reflectance infrared (ER IR) spectroscopy, gravimetric analysis, contact angle and thickness measurement. Initial reaction with KOH transforms the polyimide surface to a potassium polyamate surface. The reaction of the polyamate surface with HC1 yields a polyamic acid surface. Upon curing the modified surface, the starting polyimide surface is produced. The depth of modification, which is measured by a method using an absorbance-thickness relationship established with ellipsometry and ER IR, is controlled by the KOH reaction temperature and the reaction time. Surface topography and film thickness can be maintained while a strong polyimide-polyimide adhesion is achieved. Relationship between surface structure and adhesion is discussed. 

Above all of these requirements, SAIE must produce products that are superior to the conventional products. In other words, low-pressure plasma SAIE is not an alternative process it should be a new approach to create superior composite materials that could not be obtained by other means, which is of utmost importance with respect to the use of LCVD. It is often mentioned that plasma polymerization was successfully used in the surface modification but that a conventional, more economical, wet chemical process later replaced it. Such an attempt to use LCVD process based only on the laboratory curiosity is an absolutely wrong approach. This aspect is explored in Chapter 12. 

In the synthesis of mixed oxides, the co-precipitation method is the most commonly used wet-chemical process. Salts of the several metals are dissolved in the same solvent (water is the most popular one). Ideally, a quantitative and simultaneous precipitation of all the cations occurs without segregation of any particular constituents in the precipitates. This ideal situation is very rare in most cases, especially more than two metal cations are involved. Differences in solubility between several precipitating phases affect the precipitation kinetics of each metal... 

Higher cost Higher proprietary formulations Precoated films Thickness restriction Resolution to Iju Wet Chemical Process High speed (10 3cm2/erg) Poor chemical resistance Poor physical resistance One or two dimensional Images... 

H. Morinaga, M. Suyama, and T. Ohmi, Mechanism of metallic particles growth and metal-induced pittings on Si wafer surface in wet chemical processing, J. Electrochem. Soc. 141, 2834, 1994. 

Sun QH et al (2009) Fabrication of aligned polyaniline nanofiber array via a facile wet chemical process. Macromol Rapid Commun 30(12) 1027-1032... 

Apart from electrochemical oxidation and reduction, the fuUerenes electron affinity can also be used in wet-chemical processes. The formation of alkali-metal fullerides is among the most important reactions with reducing agents. Here, the respective elemental metal and C ) are reacted in solid phase, for example, by heating in a closed ampoule. The stoichiometry of the resulting products is controlled by the ratio of fuUerene and metal ... 

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