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Copyright of Journal of Mining & Metallurgy. Section B: Metallurgy is the property of Journal of Mining & Metallurgy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mining & Metallurgy. Section B: Metallurgy is the property of Journal of Mining & Metallurgy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mining & Metallurgy. Section B: Metallurgy is the property of Journal of Mining & Metallurgy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ti–CrNi alloy coatings with 20, 40, 60 and 80 at-%Ni were prepared on Ti6Al4V alloy surface by double glow plasma surface alloying technique. The cyclic oxidation behaviour of the coatings was investigated at 750, 850 and 950°C. The results show that each coating has a complete structure of settled layer, mutual diffusion layer and sputtering affected zone. When the Ni content was 40 at-%, the Ti–CrNi alloy coating showed the best cyclic oxidation resistance. The oxide scale with ‘Cr2O3film+NiO film’ structure showed the best resistance to peeling. [ABSTRACT FROM AUTHOR]

Three commercial ferritic stainless steels were investigated at 1200 °C by a thermogravimetric analyser (TGA) in air. The oxidation kinetics of the ferritic stainless steels differed significantly. The adhesion of the Cr2O3 scale, the morphology of the SiO2, with or without (Cr, Mn)3O4 spinel on the top can greatly influence the oxidation and the degradation behaviour of the steels. Although the SUS430 steel had less Cr among the ferritic stainless steels (16.2 wt% Cr), it did not show more degradation behaviour than the B443NT steel (21.0 wt% Cr). The spallation of the protective oxide scale on the B443NT steel was caused by vacancy condensation at the scale/substrate interface where the SiO2 particles were and the developed compressive stresses within the oxide scale during oxidation. (Cr, Mn)3O4 spinel on the top of the Cr2O3 scale on the B445J1M steel influenced its evaporation rate. The thermodynamic aspect of the chemical composition and oxidation atmosphere of the Fe-Cr-O system was also discussed. [ABSTRACT FROM AUTHOR]

The Ta coating with corrosion resistance is grown on the γ-TiAl substrate by double-glow plasma surface metallurgy technique, followed by the electrochemical test in 10 wt%, 20 wt% HCl and 10 wt%, 40 wt% H2SO4 solution. The data of nanohardness and elastic modulus are collected by the nanoindention test. The adhesion strength of Ta coating is investigated by means of the scratch test. The study of corrosion resistance is performed using potentiodynamic polarization and electrochemical impedance spectroscopy and measured by SEM and X-ray diffraction. Results highlight that the Ta coating is tightly bonded to the γ-TiAl substrate, consisting of the deposition layer and diffusion layer. Experimental data indicate that the Ta coating presents excellent corrosion resistance, which is confirmed by the high values of polarization resistance ( Rp) and the low values of corrosion current density ( icorr). The surface nanohardness of the Ta coating is improved from 3.41 to 7.29 GPa, nearly twice of that of the substrate. The Ta2O5 formed on the coating is able to hold back the penetration of adverse ions inwardly, owing to its dense structure and adhesion effect. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

To solve the poor tribological property of the γ-TiAl alloy, the duplex treatment of plasma carburisation on plasma alloying γ-TiAl with tungsten was conducted by double glow plasma surface alloying technique. The results indicated the alloying layer consisted of TiC and W2C phase, metallurgically adhered to the substrate. In terms of the H/E and H3/E2 ratios, the duplex treated specimen was nearly three times larger than the untreated specimen. The wear property of the specimens was tested on a pin-on-disk tribometer by rubbing against Si3N4 ceramic ball. The wear rate of the duplex-treated specimens is 1·056×10−4 mm3 N−1 m−1, which is only 25·9% of that of the untreated specimens. The relationship between alloying layer mechanical property and wear resistance indicates that the carbide phase formed within the alloying layer contributes to the improvement of the wear performance. [ABSTRACT FROM AUTHOR]

The Cr-Nb alloyed layer formed on the surface of low carbon steel by double glow plasma surface alloying could improve the corrosion resistance of the substrate. The morphology and microstructure of the layer were investigated by scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction. The average thickness of the alloyed layer is approximately 18 μm. A uniform and dense Cr-Nb alloyed layer had been synthesized without any cracks and holes on the surface of low carbon steel. The corrosion behavior of the alloyed layer was evaluated by polarization experiments in 3.5wt% NaCl solution using a CHI660D type electrochemical workstation. Potentiodynamic polarization and electrochemical impedance spectroscopy were applied to evaluate the corrosion resistance of the alloyed layer. Compared with the substrate, the Cr-Nb alloyed layer exhibited higher corrosion potential, lower corrosion current density and larger charge transfer resistance. The result presents that Cr-Nb alloyed layer has significantly modified the corrosion resistance of low carbon steel. [ABSTRACT FROM AUTHOR]

Zirconium R60702 weldment was achieved by tungsten inert gas welding. Hot acid corrosion and electrochemical corrosion tests were performed on the specimens taken from the base metal (BM), the heat-affected zone (HAZ), and the weld zone (WZ) of the weldment in 75 wt% sulfuric acid. Metallographic examination and X-ray diffraction (XRD) analysis showed that the impurity generating in the weldment during welding was zirconium dioxide. Cumulative mass loss test demonstrated that the BM exhibited good resistance to hot acid corrosion, the HAZ less, and the WZ least. Scanning electron microscope images illustrated that the corrosion mechanism of the BM was pitting whereas that of the WZ was inter-granular corrosion. In contrast, pitting and inter-granular co-existed in the HAZ. Anodic polarization and electrochemical impedance spectroscopy tests showed similar result to that of the hot acid corrosion test. In the electrochemical corrosion condition, the WZ had worse corrosion resistance than the other two parts. Therefore, the WZ is the key area of corrosion-resistance protection of the Zr R60702 weldment. [ABSTRACT FROM AUTHOR]

The Al-Zn-Si coating was deposited on Q235 steel by thermal spray technology. The corrosion behaviour of the coating in simulated marine environments has been investigated through neutral salt spray test (NSS) and electrochemical test. Furthermore, the microstructure and the morphologies of the coating were detected by means of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results showed that the coating exhibited a dense homogeneous lamellar microstructure without obvious defects. There were different corrosion periods of the coating in the simulated marine environment, such as dissolution of Zn and Al particles, flocculent morphology, acicular crystals and self-sealing behaviour caused by corrosion products. Ultimately, a dynamic equilibrium was formed between the consumption of the coating and the generation of the corrosion product layer. Moreover, Tafel curves indicated that the Ecorr and Icorr of the coating after NSS were lower than the substrate that had a sufficient driving force of the cathodic protection. [ABSTRACT FROM AUTHOR]

Zirconium (Zr) alloying layer was formed in the TC11 surface by using the double glow plasma surface alloying technique. The microstructure, surface hardness and oxidation resistance of the alloying layer were investigated by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectrometry, respectively. The results showed that the alloying layer consisted of a compact and homogeneous Ti-Zr mutual diffusion layer, and the surface alloying elements all displayed gradient distributions. The zirconium alloying layer enhanced the surface hardness by solution strengthening. The improvement of TC11 oxidation resistance was due to the formation of compact and uniform oxide scales, which was consisted of ZrO2 as the major phase and TiO2 as the minor phase. [ABSTRACT FROM AUTHOR]

The hot-dipped zinc-aluminum alloy coating was used to avoid galvanic corrosion problems of titanium-aluminum alloy. The microstructure and corrosion properties of the coating were investigated by scanning electron microscopy, electrochemical measurement, and immersion test. The microstructure indicated that the coating consisted of outermost layer and middle interdiffusion layer, which metallurgically combined with the substrate. The electrochemical properties indicated that the coating on the titanium alloy decreased the electrochemical potential difference of galvanic couple. The corrosion current density showed that aluminum alloy contact with the coating changed the electrode, in other words, aluminum alloy specimen turned out to be the cathode in the galvanic couple. Immersion test was carried out to evaluate the performance of coating for galvanic corrosion, results confirmed that aluminum alloy contacted with coating on titanium-aluminum alloy exhibited less surface corrosion. [ABSTRACT FROM AUTHOR]

In order to improve corrosion resistance of pure titanium in strong acid solution, the tantalum modified layer was formed on the pure titanium surface by double glow plasma surface tantalumising. The modification layer was comprised of deposition layer and diffusion layer, which metallurgically adhered to the substrate. Tantalum element decreased with the case depth. The corrosion resistance of the tantalum modified layer in HCl solution was investigated by weight loss method and electrochemical measurements, and the corrosion morphology (SEM) was studied by SEM and X-ray diffraction. The annual corrosion rate of the modified layer was only 12 and 21% of pure titanium in 10 and 20 wt-% HCl solution respectively, and the corrosion rate was still small in 30% HCl solution. In concentrated acid for 120 h, it was found that there was significant pitting corrosion on the surface of pure titanium, while no pitting corrosion could be perceived in the modified layer. The main reason for the good corrosion resistance was a compact, stable tantalum oxidation film formed at the surface of the modified layer. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

Quantitative structure-activity relationships (QSARs) based on the octanol/water partition coefficient were employed to predict acute toxicities of 36 substituted aromatic compounds and their mixtures. In this study, the model developed by Verhaar et al. was modified and used to calculate octanol/water partition coefficients of chemical mixtures. To validate the model, acute toxicities of these chemicals were measured to Vibrio fischeri in terms of EC 50 . The results indicated that the obtained QSAR models could be used to predict toxicities of samples consisting of these substituted aromatic compounds, individually or in combinations. The obtained equations were proved to be robust enough by using the leave-one-out test method. By classifying these chemicals into two groups, polar and non-polar, the toxicities of chemical mixtures within each group can be predicted accurately from their calculated partition coefficients. [ABSTRACT FROM AUTHOR]

The article reports on estimation of the sorption of substituted aromatic compounds onto modified clay. Substituted aromatics have been used extensively in the chemical industry. They are a class of dangerous toxic compounds and have been released into the environment. Their environmental behavior and ecological effects should be anticipated. The purpose of this work was to study the sorption behavior of nonclass-specific sets of 27 substituted aromatic compounds on modified clay and to produce a predictive model.

This article presents information related to determination and estimation of Aqueous Solubilities and n-Octanol. With the development of industry, more and more chemicals, such as pesticides, detergents, plasticizers and some other industrial products are being introduced into! environment and most of them are harmful to human. However, the environmental behaviors of xenobiotics are closely connected to their properties such as solubility, n-octano 1/water partition coefficient, which are regarded as the main parameters controlling environmental fate.

The purpose of this article was to study the sorption behavior of nonclass-specific sets of 28 substituted aromatic compounds in the Yangtse River sediment and to produce a predictive model. Substituted aromatics have been used extensively in the chemical industry. They are a class of dangerous toxic compounds and have been released into the environment. The measured or accurately estimated soil sorption coefficients of chemicals are critical importance for their environmental risk assessment. The sorption coefficients for the sediment and the octano/water partition were determined using the shake-flask method according to the OECD guidelines for testing of chemicals.