The paper considers the physicochemical and physicomechanical aspects of formation of an adhesive contact between the surface of the substrate (copper, nickel, cobalt alloys; iron low-alloy; stainless steel) and a tungsten coating obtained by chemical vapor deposition (CVD) using tungsten hexafluoride WF6 as a precursor of tungsten. The number of possible chemical reactions occurring during the deposition of tungsten-containing layers was limited based on the literature data. A thermodynamic analysis of feasibility of these reactions was carried out. The effect of the reaction products on the adhesive contact of the coating was estimated. The results of the study complement practical research on the deposition of tungsten-containing layers and provide a direction for further improvement of the CVD process.
With the rapid advancement of wireless communication technologies, electromagnetic pollution and interference have intensified significantly, posing a serious threat to human health, the safety of electronic devices, and military information security. Consequently, the development of high-performance electromagnetic wave absorbing materials with the characteristics of “thin thickness, wide bandwidth, light weight, and strong absorption” has become a hot topic in the field of materials science. Among the numerous candidate materials, the electromagnetic wave absorbing materials composed of magnetic metals (especially cobalt (Co) and nickel (Ni)) and carbon matrix have shown great application potential due to their adjustable electromagnetic parameters, low density, good chemical stability, and the ability to optimize impedance matching and attenuation characteristics through the synergistic effect. This paper aims to systematically and deeply sort out and analyze the performance regulation strategies and preparation methods of CoNi/C composite electromagnetic wave absorbing materials, providing a systematic strategy for their future preparation and regulation, and looking forward to the future research direction of the materials.
Acomprehensive thermo-acoustical investigation of diethyl ether and 1-hexanol has been carried out at four different temperatures (298, 303, 308, and 313 K). Experimentally measured parameters include density (ρ), viscosity (η), and ultrasonic velocity (U). Using experimental data, various derived thermo-acoustical parameters such as acoustic impedance (Z), intermolecular free length (Lf), internal pressure (πi), Wada’s constant (W), molar enthalpy, and inverse relaxation time (1/τ) were evaluated. Further, excess properties including excess molar volume ( V_m^E ), excess acoustic impedance (ZE), excess ultrasonic velocity (UE), excess viscosity (ηE), and excess intermolecular free length ( L_f^E ) were calculated to analyze deviations from ideal behavior and intermolecular interactions. Temperature dependence reveals systematic variation of cohesive forces with increasing temperature. Strong associative hydrogen bonding in 1-hexanol leads to higher viscosity, lower molar volume and higher acoustic impedance compared to diethyl ether, which predominantly exhibits dipole–dipole and dispersive interactions. The sign and magnitude of excess parameters indicate the strength and nature of molecular interactions and structural rearrangements within the liquid systems. The present study provides valuable thermodynamic data for molecular interaction analysis and industrial process modeling.
The enthalpies of combustion of cobalt(II) octacarboxyphthalocyaninate (CoPc(COOH)8) and tetracarboxyphthalocyaninate (CoPc(COOH)4) are studied by bomb calorimetry using an IKA C6000 isoperibol calorimeter. The enthalpies of dissolution of crystalline CoPc(COOH)8 in aqueous KOH solutions of varying concentrations at a temperature of 298.15 K are determined by the direct calorimetric method.
CO2 methanation offers a promising approach to addressing both the greenhouse effect and the shortage of natural gas resources, making the development of efficient and stable catalysts highly imperative. Ni-based catalysts have attracted significant interest due to their low cost, high CO2 conversion, and excellent CH4 selectivity. In view of this, a series of NiMg-cop catalysts with varying Ni/Mg molar ratios and Ce loadings were synthesized by co-precipitation, and the effects of preparation methods and Ce doping on CO2 methanation performance were investigated. The results indicated that the catalyst 0.75NiMg-cop exhibited the excellent catalytic performance, holding 85.6
