Microstructure and Oxidation Behavior of Ni–TiO2 Composite Coating at High Temperature

Oxidation of Metals - Ni-based composite coatings are considered to improve the oxidation resistance of stainless steel. In this study, Ni–TiO2 composite coatings were electrodeposited onto...     

The Composition and Physicochemical Properties of PbO2–TiO2 Composite Materials Deposited from Colloid Electrolytes

Protection of Metals and Physical Chemistry of Surfaces - The effect of the deposition conditions from colloid electrolytes on the chemical and phase composition, texture and electrocatalytic...     

Study of the Adsorption of the IFKhAN-92 Inhibitor on the Surface of Chromium–Nickel Steel from Hydrochloric and Sulfuric Acid Solutions by Ellipsometry

Protection of Metals and Physical Chemistry of Surfaces - The method of reflective ellipsometry has been used to study the adsorption of the IFKhAN-92 inhibitor that is a triazole derivative on...     

First Principles Study of Structural Stability and Magnetic Property of Non-equilibrium Co–Mo Alloys

First principles calculations are carried out to investigate the structural stability of several non-equilibrium intermetallic phases in the cobalt(Co)–Mo system using spin polarized projected augmented-wave potentials. It is revealed that the Co3Mo, CoMo, and CoMo3 alloys are energetically favored to be in D019, B11, and A15 structures, respectively,and that the magnetic moments of Co atoms would decrease rapidly with an increasing percentage of Mo content and would most probably disappear when the content of Mo is no less than 50 at%. Generally, the calculated results in the present work match well with the available experimental observations.     

A Comparative Study on the Effect of MWCNT as Reinforcement on the Corrosion Parameters of Different Ni–W/MWCNTs Nanocomposite Coatings in Various Corrosive Media

Nickel–tungsten multi-walled carbon nanotubes (Ni–W/MWCNTs) nanocomposite coatings were co-electrodeposited in the ammonium-free bath by means of constant direct current coulometry. The results indicate that the amount of MWCNTs incorporated into the nanocomposite coatings has a key role in the improvement of their microhardness and corrosion resistance. The corrosion behavior of the coatings was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy methods in three corrosive media of 3.5 wt% NaCl, 1.0 M NaOH, and 0.5 M H₂SO₄. The experimental data of the corrosion current density (j_corr), corrosion rate (CR), the polarization resistance (R_p), and microhardness indicate that the presence of MWCNTs in coatings improves the quality of those coatings. The surface morphology of the coatings and the elemental analysis data were obtained by scanning electron microscopy and energy dispersive X-ray microanalysis respectively. As the results showed, the coatings were uniform and crack-free in the presence of 5.3 wt% carbon. Also, a microhardness test revealed that the nanocomposite coating containing 5.3 wt% carbon obtained in an ammonium-free bath which provided the higher content of tungsten had the highest hardness value among others.     

Adsorption and photocatalytic degradation of phenol over TiO_2/ACF

1　INTRODUCTIONToday ,waterpollutioncausedbyhazardousor ganicchemicalsusedinindustryandagricultureisaveryseriousproblem ,thedeeptreatmentandreuseofwastewaterisveryindispensable[1] .Titaniumdioxideheterogeneousphotocatalysiscandegrademostofor ganicpollutantscompletelyintoCO2 ,H2 Oandinor ganicacid ,andhasshowntremendouspotentialityinthetreatmentofwastewater[2 ] .TiO2 powderhasbeenthemostwidelyusedphotocatalystinthephoto catalyticprocessduetoitsstablechemicalproperties ,easyaccessandcheapc…     

Study on Microstructures and Properties of Electro Brush-plating Composite Coatings

RECENTLY,composite materials and compositecoatings have been attracting increasing attention.It iswell known that,composite materials and compositecoatings possess unusual mechanical andphysicochemical properties.As one of the importantfunctional plating deposition in the surface treatmenttechnology,the electro brush-plating has been widelyused by engineers because of its excellent convenienceand good performances.In this paper,compositecoatings were prepared using improved electrobrush-pla…     

A Study of the Durability of Aeolian Sand Powder Concrete Under the Coupling Effects of Freeze–Thaw and Dry–Wet Conditions

JOM - The deterioration processes of aeolian sand powder concrete under freeze–thaw and dry–wet conditions have been studied. The pore characteristics, hydration products, and...     

Effects of MgO/Al2O3 ratio on viscous behaviors and structures of MgO–Al2O3–TiO2–CaO–SiO2 slag systems with high TiO2 content and low CaO/SiO2 ratio

The effects of MgO/Al₂O₃ ratio on the viscous behaviors of MgO–Al₂O₃–TiO₂–CaO–SiO₂ systems were investigated by the rotating cylinder method. Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag. The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al₂O₃ ratio increases from 0.82 to 1.36. The break point temperature and liquidus temperature of slag initially decrease and subsequently increase. The complex viscous structures are gradually depolymerized to simple structural units. In conclusion, with the increase of MgO/Al₂O₃ ratio, the degree of polymerization of slag decreases, which improves the fluidity of slag. The variations of liquidus temperature of slag lead to the same changes of break point temperature.     

Anti-Corrosion and Tribo-Mechanical Properties of Co-deposited Zn–SnO_2 Composite Coating

Zn–Sn O2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution.The effect of Zn2?and Sn O2 concentrations in deposited bath on the mechanical properties and morphological characteristics of the composite coatings were examined.The characterizations of the sample were analyzed using scanning electron microscopy couple with energy dispersive spectroscopy(SEM/EDS),X-ray diffraction(XRD) and atomic force microscopy(AFM).The electrochemical degradation behavior of the samples in 3.65 wt.% Na Cl solution was studied using potentiodynamic polarization technique and characterized by high-resolution optical microscope.From all the fabricated composite coatings,obvious diffraction peaks were observed with Zn-7Sn-S-0.3V film with Zn2Sn7,Sn,Zn2Sn5 and Zn phases,confirming the presence and formation of Zn–Sn O2 coating.The XRD pattern shows that the presences of Sn O2 particle remarkably play a major role in the precipitation and orientation of the alloy matrix.From the SEM/EDS and AFM results,the deposits show that composite particle and proper bath composition have strong influence on the microstructure.An enhanced corrosion resistance was attained as a result of the induced particles.     

Structural state of the claddings of fuel elements of the BN-600 reactor prepared from cold-deformed 16Cr–15Ni–2Mo–2Mn–Ti–V–B steel: Study using the method of high-resolution neutron diffraction

The applicability of the method of high-resolution neutron diffraction for determining defects (dislocations) in the bulk of a material is shown based on the example of a standard sample of deformed copper. The structural state of several samples of fuel-element claddings made of cold-worked steel 16Cr–15Ni–2Mo–2Mn–Ti–V–B (grade ChS68-ID) used in the BN-600 reactor, which were prepared by two producers, i.e., at the PJSC Mashinostroitel’nyi Zavod (MSZ) and at the PJSC Pervoural’sk Novotrubnyi Zavod (PNTZ), have been investigated. The conclusion has been drawn that the claddings have a texture in which the crystallographic planes of grains are oriented along the axis of the shells. It has been shown that the main defects in these claddings are edge dislocations; their density has been determined.     

A Study of the Radiolysis Products of the Tri-n-Butyl-Phosphate–Isopar-M–HNO3 System before and after Regeneration with Carbonates of Organic Bases

Protection of Metals and Physical Chemistry of Surfaces - By measuring the hydrodynamic characteristics (viscosity, density of extraction mixture, and interfacial tension) and determining the...     

Electrosynthesis and physicochemical properties of α–PbO2–CeO2–TiO2 composite electrodes

In order to investigate the effect of solid particles dopants on physicochemical properties of α-PbO₂ electrodes, α-PbO₂ composite electrodes doped with nano-TiO₂ and nano-CeO₂ particles were respectively prepared on Al/conductive coating electrodes in 4 mol/L NaOH solution with addition of PbO until saturation by anodic codeposition. The electrodeposition mechanism, morphology, composition and structure of the composite electrodes were characterized by cyclic voltammogram (CV), SEM, EDAX and XRD. Results show that the doping solid particles can not change reaction mechanism of α-PbO₂ electrode in alkaline or acid plating bath, but can improve deposition rate and reduce oxygen evolution potential. The doping solid particles can inhibit the growth of α-PbO₂ unit cell and improve specific surface area. The diffraction peak intensity of α-PbO₂-CeO₂-TiO₂ composite electrode is lower than that of pure α-PbO₂ electrode. The electrocatalytic activity of α-PbO₂-2.12%CeO₂-3.71%TiO₂ composite electrode is the best. The Guglielmi model for CeO₂ and TiO₂ codeposition with α-PbO₂ is also proposed.     

Microstructure and Wear Resistance of a Ni–Fe–Co–P/CeO2 Composite Coating after Heat Treatment

Protection of Metals and Physical Chemistry of Surfaces - To extend the service time of #45 steel, Ni–Fe–Co–P alloy coatings were prepared on workpieces. CeO2 nanoparticles were...     

Microstructural Study of Fe-Cr-Al/Al Composite Coatings During Oxidation and Sulfidation at 900℃

The microstructure of a composite coating system,which was composed of an inner layer of Fe-Cr-Al and an outer layer of aluminum,was studied after it was respectively oxidized and sulfurdized at elevated temperatures. Apart from the Al2O3 scale formed on the surface,the microstructure of the composite coatings exposed at 900℃ in air for 4h was a three-layer structure. The first layer consisted of a solid solution of Cr and Fe in α aluminum and an intermetallic compound FeAl3,while the second layer was a single phase of the aluminide and the third layer still remained the same appearance as the original Fe-Cr-Al coating. The microstructural observation of the specimen tested at 850-900℃ at low oxygen pressure and high sulfur pressure for 576h revealed that the surface coatings of the specimen had transformed into a duplex structure containing an outer layer and a thicker aluminide layer beneath. X-ray diffraction results showed that the out layer was composed of Al2S3 and Al2O3 and that AlCrFe2 was the main phase composition of the aluminide layer,with a few of Al2S3 and Al2O3 accompanied.