Catalytic oxidation of CO on metals involving an ionic process in the presence of H2O: the role of promoting materials

A new catalytic oxidation of CO is enhanced by H2O molecule on the Pt and Au with specific promoting materials where the rate-determining reaction of HCOO(a) + OH → CO2 + H2O is promoted by repeated contribution of OH− anion via messenger molecule H2O.

Abrasion Under Humide Condition for Tool Steels H-13 and AISI D-2

In the present work, is developed the tribologic characterization of steels AISI H-13 and D-2, submitted to nitruration ionic process to determine wear resistance in aqueous conditions. Wear test are realized with an abrasion wear tool in an aqueous environment, designed and constructed by SEPI, ESIME, IPN, according to the norm ASTM G105-89. The aim of this investigation is to use a new material at lower prize which has an excellent wear resistance properties for high abrasion in aqueous environments, as occurs in several cases as mining industry equipments.

Solubility in the CuCl2-NaCl-H2O System and Hydration Analysis in the Case of Complexation

The solubility diagram in the title system was studied at 25 °C. The results were compared with contradictional isotherms of other authors and one isotherm being in error was localized and rejected. The reliable solubility branches were treated with hydration analysis, which brings information on ionic processes in saturated solutions. Formation of coordination anions such as [CuCl3]- and [CuCl4]2- was found to be the main ionic process in saturated solutions in spite of the non-existence of the corresponding solid phase. The information obtained by this method for systems where hydration of components and complex formation take place simultaneously is demonstrated and discussed for the first time. A possibility of calculation of activity coefficients of the solute on both crystallization branches is discussed.

Analysis and lattice imaging of a transitional event on garnets

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.

Reciprocity failure of photographic materials at short exposure times

Recent work in which photographic materials were exposed at low temperatures (Berg and Mendelssohn 1938; Webb and Evans 1938; Berg 1939 a ; Evans and Hirschlaff 1939) has given results which can be explained by the assumption that an electronic and an ionic process occur in the formation of the latent image (Trivelli 1928; Gurney and Mott 1938). At low enough temperatures these two processes are separated because the ionic mobility is reduced to zero and the ionic process is postponed until the emulsion is warmed up prior to development, whereas the electronic mobility is but little affected. It should be possible to separate these two processes even at room temperature, because the electrons are much more mobile than the ions, and thus for sufficiently brief exposures the electronic process should be over before the heavier ions have moved appreciably. If this were correct, no difference would be found between exposures sufficiently short to make certain of this separation, and shorter exposures still. In other words, reciprocity failure, the occurrence of which has been accounted for by the electronic and ionic processes taking place side by side (Gurney and Mott 1938), should disappear. The shape of the reciprocity curve is well represented by a catenary over the range hitherto investigated (Webb 1935). According to the present argument the catenary-like curve would be ex­pected to bend over and become horizontal at its short exposure end. The longest exposure on the horizontal part of the curve should then bear some relation to the mobility and concentration of movable silver ions, and, in so far as these properties depend on temperature, the position of the “bend-over point” should depend on temperature also. Experiments on these lines are reported below.