The influence of micro plasma oxidation (MPO) process conditions on creation of the Al2O3 coatings on aluminum alloy D16 was studied using EPR technique. Aluminum alloy D16 contains alloyed transition metals such as Cu, Mn, Fe, Ni, Ti, being incorporated into the coatings structure during MPO processes. EPR data on transition metal ions allow estimating an appearance of a high temperature phase of Al2O3 due to difference in incorporation coefficients and in the EPR parameters of transition metal ions in low and high temperature Al2O3 phases of MPO coatings. These data show that no high temperature Al2O3 phases were created during anodic MPO process.
The binding energy of Cooper pairs has been calculated for the case of d-wave symmetry of the superconducting gap in layered cuprate superconductors. We assume that Cooper pairs are formed by the short range potential and then derive the binding energy in the form Δ𝒌𝒒 =Δ𝑥(𝒒)cos𝑘𝑥 𝑎 +Δ𝑦 (𝒒)cos𝑘𝑦 𝑎 +Ω𝑥(𝒒)sin𝑘𝑥𝑎 +Ω𝑦(𝒒)sin𝑘𝑦𝑎 , where 𝒒 is a total momentum of the pair. Numerical solutions of the self-consistent system of the integral equations for quantities Δ𝑥 (𝒒) , Δ𝑦 (𝒒) and Ω𝑥(𝒒), Ω𝑦 (𝒒) along different lines in 𝑞𝑥, 𝑞𝑦 plane have been obtained. Anisotropy of the depairing total momentum (or depairing current) has been calculated.
Anthraquinone paramagnetic complexes have been used to study electron-acceptor centers on the surface of alumina modified with alkali metal ions (Li+, Na+, K+). Complexes have been characterized by CW EPR, ENDOR and pulse EPR (HYSCORE) techniques. It has been shown that alkali metal ions decreased the strength of electron-acceptor centers due to the inductive effect. As a result the concentration of anthraquinone complex with two Lewis acid sites (LAS) decreased, but the concentration of complex with one LAS increased with the increasing of alkali metal content. At large alkali metal concentration other kinds of anthraquinone paramagnetic complexes are formed, that are anthrasemiquinone weakly bound with LAS as well as anthrasemiquinone ion pair with alkali metal cation (lithium).
