NEW WEAR-RESISTANT COBALT-BASED ALLOY: EFFECT OF SILICON AND CARBON ON STRUCTURE AND TRIBOTECHNICAL CHARACTERISTICS. Part 1

The paper examines the influence of the increased content of silicon and carbon on the tribotechnical characteristics, structure and phase composition of a new Co–Cr–W–C system wear-resistant alloy. It was found that a joint increase in the content of silicon and carbon (despite the increase in the friction coefficient) leads to a significant decrease in the values of the wear intensity and linear wear. This is associated with the formation of a dense homogeneous oxide film. It is shown that joint doping with silicon and carbon to the upper doping limit provides a slight decrease in weight gain at temperature of 1100 °C.

Влияние гамма-облучения на фазовые переходы в политетрафторэтилене, допированном диоксидом кремния растительного происхождения

The effect of gamma irradiation and doping with silicon dioxide on the first-order solid-state phase transition in polytetrafluoroethylene is studied by the differential scanning calorimetry method. A quantitative analysis of the profiles of the heat capacity peaks is carried out on the basis of the theory of diffuse phase transitions. It is shown that the elementary volume of the phase transformation depends on the γ irradiation and the concentration of silicon dioxide.

Atomistic Modeling of an MFM ferroelectric capacitor made of HfO2:Si

ABSTRACT:Using ab initio simulation, we study a ferroelectric layer of a few nanometers made of hafnia (HfO2) under the influence of Si doping with TiN electrodes. We evaluate the orthorhombic phase of Pca21 symmetry, its ferroelectric switching and the incidence of doping with silicon. We show that the ferroelectric switching can involve a 90° characteristic angle with corresponding activation energy which is lowered by a factor three due to Si doping at 3% at. A full MFM (Metal-Ferroelectric-Metal) model is derived in order to simulate finite-size effects. This model is compatible with a reversal of a polar HfO2:Si with a (111) preferential orientation. Validity and usefulness of such a model are discussed for ferroelectric devices optimization.

Photoelectrochemical Characterization of Sprayedα-Fe2O3Thin Films: Influence of Si Doping andSnO2Interfacial Layer

α-Fe2O3thin film photoanodes for solar water splitting were prepared by spray pyrolysis ofFe(AcAc)3. The donor density in theFe2O3films could be tuned between1017–1020 cm-3by doping with silicon. By depositing a 5 nmSnO2interfacial layer between theFe2O3films and the transparent conducting substrates, both the reproducibility and the photocurrent can be enhanced. The effects of Si doping and the presence of theSnO2interfacial layer were systematically studied. The highest photoresponse is obtained forFe2O3doped with 0.2% Si, resulting in a photocurrent of 0.37 mA/cm2at 1.23 VRHEin a 1.0 M KOH solution under 80 mW/cm2AM1.5 illumination.