Optimization of the thermoelectric properties of poly(nickel-ethylenetetrathiolate) synthesized via potentiostatic deposition

The coordination polymer poly（nickel-ethylenetetrathiolate） （poly（Ni-ett））, formed by nickel（Ⅱ） and 1,1,2,2-ethenetetrathiolate （ett）, is the most promising N-type organic thermoelectric material ever reported; it is synthesized via potentiostatic deposition, and the effect of different applied potentials on the optimal performance of the polymers is investigated. The optimal thermoelectric property ofpoly（Ni-ett） synthesized at 0.6 V is remarkably greater than that of the polymers synthesized at 1 and 1.6 V, exhibiting a maximum power factor of up to 131.6μW/mK2 at 360 K. Furthermore, the structure-property correlation ofpoly（Ni-ett） is also extensively investigated. X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） analyses revealed that the larger size of crystalline domains and the higher oxidation state of poly（Ni-ett） synthesized at 0.6 V possibly results in the higher bulk mobility and carrier concentration in the polymer chains, respectively, accounting for the enhanced power factor.

Study on Electrodeposition of Ho-Co Alloy in Dimethylsulfoxide

Co deposition of Ho with Co was studied in dimethylsulfoxide (DMSO) by cyclic voltammetry and potentiostatic deposition at room temperature. The cyclic voltammogram shows that the codeposition of Ho with Co can be attributed to induced codeposition mechanism, for the codeposition potential is more negative than the deposition potential of Co but positive than that of Ho. For the potentiostatic deposition used in Ho Co alloys preparation, the results indicate that in the range of selected concentration the potential is the main factor determining the content of Ho in Ho Co alloys, while the composition of Ho 3+ and Co 2+ in electrolyte solution has less influence. According to the analysis of X ray diffraction, EDAX, and scanning electron microscopy, uniform, compact and amorphous films on Cu can be obtained at -1 8 V (vs.SCE) in 0 165 mol·L -1 Ho(NO 3) -0 135 mol·L -1 CoCl 2 DMSO solution.

Influence of pH on the Formation, Composition and Protectiveness of Fluoride Conversion Film Deposited on AZ31 Magnesium Alloy in KF Solution

In deaerated 0.1 M KF solution at pH 5, pH 7.5 and pH 9, fluoride films were deposited on AZ31 magnesium (Mg) alloy at − 1.4 V vs saturated calomel electrode (SCE). The morphology, phase composition, elemental and compositional depth distribution of different fluoride films and their influences on the corrosion resistance of AZ31 Mg alloy were explored in detail. The results indicated that the films deposited at weak acidic and nearly neutral pH consisted of two layers with amorphous Mg(OH)_(2) and MgF_(2) as the inner layer, and Mg(OH)_(2), MgF_(2) and KMgF_(3) crystals the outer layer. The film deposited at alkaline pH was a monolayer structure consisting of amorphous Mg(OH)_(2) as the major constitute and MgF_(2) as the minor constitute. The protectiveness of fluoride film was intimately related to its composition and structure. The content and crystal regularity of KMgF_(3) were the two main factors influencing the protectiveness of fluoride film. The fluoride film deposited at pH 7.5 offered the best protection to AZ31 Mg alloy.