Alteration of the Acid-Base Properties of the Oxidized Surface of Disperse Aluminum during the Adsorption of Ammonium Compounds and the Antifriction Effect
| Autor: | N. N. Rozhkova, M. M. Sychev, M. O. Silivanov, A. G. Syrkov |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Base (chemistry) 010405 organic chemistry Inorganic chemistry chemistry.chemical_element 010402 general chemistry Condensed Matter Physics 01 natural sciences Acid dissociation constant Ammonium compounds 0104 chemical sciences Gas phase Adsorption chemistry Aluminium Materials Chemistry Ceramics and Composites Lewis acids and bases Lubricant |
| Zdroj: | Glass Physics and Chemistry. 44:474-479 |
| ISSN: | 1608-313X 1087-6596 |
| DOI: | 10.1134/s1087659618050206 |
| Popis: | The number of active centers of disperse aluminum powder is determined by the spectrophotometric method using the Hammett indicators in the range of pKa values of 0.3 to 14.2; alteration of the distribution of the donor-acceptor sites on the surface as a result of the adsorption of quaternary ammonium compounds (QACs) from the gas phase is studied. The curves of the distribution of adsorption sites of aluminum-based powders are built depending on the ionization constant pKa of the indicators. A sharp decrease in the number of active sites in the Lewis acid sites region is detected for Al/(A + T) sample, where alkamon (A) and triamon (T) are jointly adsorbed. The number of sites is halved at pKa =–0.3, 5, and 9.5. We reveal that the antifriction effect of a lubricant is enhanced as the acidity of the surface of the powder with the adsorbed quaternary ammonium compounds is decreased. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink