The decrease of the corrosion resistance of aluminum alloys of different doping systems results from their phase and surface heterogeneity. Operation in environments of various aggressiveness contributes to the emergence of local types of corrosion damage on aluminum alloys. This results in premature failure of metal structures. A rather wide range of coatings are used to protect aluminum alloys, among which conversion coatings occupy a significant share due to their production effectiveness and compatibility with many paint systems. In this regard, the possibility of fabrication of submicron protective conversion coatings on AMg3 aluminum alloy in molybdenum converting media has been studied in this work. Electrochemical studies have shown that the addition of ammonium nitrate to the molybdenum-converting compound does not affect subsequent treatment (filling) of the resulting coatings in a corrosion-inhibitor solution. The optimal time for fabrication of coatings and its subsequent filling has been revealed. It has been shown that the studied molybdenum-conversion coatings are similar in protective properties to the traditional chromate coating.

Studies of contaminants obtained by spraying ITER-grade Be on a quasi-stationary plasma gun facility QSPA-Be are presented. Contaminating films, consisting mainly of Be and O in approximately equal proportions, were deposited on substrates of quartz, sapphire, single crystalline silicon (SC-Si) and NaCl crystal. Characterization of the deposits was performed using SEM, XPS, EBS, AFM, SE, TEM&SAED and micro-interferometry showing polycrystalline BeO films similar as found in JET-ILW. Films on SC-Si and NaCl were used to characterize their composition and morphology. The cleaning rates in the 81.36 MHz RF discharges in He or D2 at 2 Pa were measured on the SC-Si target. The measured etching rate of the deposited films was several times higher than the rate calculated from the theoretical value of beryllium oxide sputtering yield. Test cleaning of these contaminants was carried out in a capacitively coupled RF discharge (CCRF) from the surface of sapphire and quartz plates, which were considered as a mock-ups of the protective window of the first mirror unit (FMU) designed for ITER divertor Thomson scattering diagnostic system (DTS).

Abstract—Aluminum alloy 1105 is related to the Al–Mg–Cu family and is used in structures operating in cold climates. This alloy is characterized by its high amount of impurities, which decreases its corrosion resistance. To protect it, the new chromate free conversion composition IFHANAL–3 has been analyzed. It is demonstrated that the use of complexing agents in this conversion composition changes the composition of the coating; however, this improves their protecting properties in comparison with similar coatings on other copper-containing alloys. In the case of aluminum alloy 1105, a higher protective effect is achieved by the introduction of nitrate into the composition of the conversion and filling the coating in solution with addition of 5‑methyl-benzotriazole.

A solution has been developed for applying protective-adhesive lanthanum-, manganese containing coatings under paintwork on the surface of magnesium alloy AZ31B instead of high toxic chromate coatings, as well as independent anticorrosive coatings under mild operating conditions, for example, for inter-operation storage of products. A solution containing 1-6 g/l La(NO3)(3)center dot 6H(2)O and 0.5-2 g/l KMnO4, allows at pH 2.0-3.0 and at a temperature 18-30 degrees C to form conversion coatings consisting of La2O3, MnO2, MgO, Mg(OH)(2) on the surface of AZ31B magnesium alloy in 2 minutes. Titanium-, zirconium-and lanthanum-, manganese-containing coatings can be used as adhesion layers under paintwork instead of high-toxic chromate coatings, and also as independent anticorrosive coatings under mild operating conditions, for example, for inter-operation storage of products. Using ellipsometry, it was found that the thickness of the cerium-containing coatings is 175 +/- 5 nm. Corrosion tests in a salt-spray chamber according to ISO 4536 (SD test) ASTM B117 have shown that the developed lanthanum-, manganese-containing coatings are superior in protective ability to the currently widely used chromate coatings and are not inferior to titanium-, zirconium-containing coatings. The developed coatings also have good adhesion properties. Ti-, Zr-and La-, Mn-containing coatings in terms of protective characteristics and adhesion strength with paintwork are not only not inferior to the currently used chromate coatings but even surpass them.

A solution has been developed for applying protective-adhesive cerium-containing coatings to the surface of the 5556 aluminum alloy in order to replace the toxic chromating process in the automotive and other industries. The developed solution contains: 5–10 g/l Ce(NO 3 ) 3 ·6H 2 O, 30–40 ml/l H 2 O 2 and 0.5–1.5 g/l gallic acid ester. Coatings with the best physicochemical characteristics are formed in a solution with pH=2–3 at a temperature of 18–25°C and a process duration of 10–15 minutes. The optimum drying temperature is 120–160°C. The coatings formed under these conditions consist of cerium oxides CeO 2 , Ce 2 O 3 and aluminum oxide Al 2 O 3 . The addition of a gallic acid ester (in an amount of 0.5–1.5 g/l) to the working solution leads to a change in the chemical composition of the forming coatings, namely, to the exclusion of CeO 2 compounds in their composition. This increases the protective ability of coatings. Corrosion tests in a salt-spray chamber have shown that the developed cerium-containing coatings are superior in protective ability to the currently widely used chromate coatings. The developed coatings have good adhesion properties and withstand exposure to high temperatures without degradation of their protective properties. Adhesion after 750 hours of salt-spray corrosion tests decreased by 13.0 and 13.8% for cerium-containing and chromate coatings, respectively. The thickness of cerium-containing coatings is 280–320 nm. The developed solution for the formation of protective adhesive coatings on aluminum is an alternative to toxic chromating solutions.

Abstract—With the correct adjustment of conditions, thermal treatment of a magnesium alloy in 5-chloro-1,2,3-benzotriazole vapor can lead to the formation of nanosized adsorption inhibitor layers on its surface, which hydrophobicizes the metal surface and increase its corrosion resistance due to inhibition of the anodic process. The protective aftereffect of the adsorption layers of 5-chloro-1,2,3-benzotriazole depends on the temperature and duration of the chamber treatment. The temperature optimal for chamber treatment of the MA8–5-chloro-1,2,3-benzotriazole system is 150°C, and the optimal duration of treatment is 1 h. Protective films formed on a magnesium alloy during chamber treatment are capable of self-assembling under these conditions. The protective effect of adsorption films formed under optimal conditions increase with an increase in the time of exposure of the samples to heat.

The behavior of carbon steel in solutions containing components of alkaline cyanide-free electrolyte for bronzing has been studied.It has been shown by the open circuit potential measurement method that contact deposition of copper on steel surface is thermodynamically possible in the solutions studied.Impedance spectrometry data show that the interaction of steel with the components of the copper-containing alkaline solution leads to the formation of a passivating film on its surface, which inhibits contact copper deposition.It has been shown that the formation of a passivation film is also possible if no copper is present in the solution.The process is significantly accelerated in solutions containing divalent copper ions due to the interaction of iron corrosion products with the divalent copperaminotris(methylenephosphonic acid) complex by the electrophilic substitution mechanism.This interaction results in the deposition of insoluble copper hydroxides on the steel surface.Data of X-ray photoemission analysis confirm that the film contains compounds of mono-and divalent copper, as well as ligand molecules.

Ionothermal synthesis of carbon nitride paved the way to a new structural allotrope—polytriazine imide. In this work, we screen available precursors for pristine polytriazine imides and for their graphitic analogs narrowing it to the melamine—urea mixture as the most promising starting material. Photocatalytic activity of materials verified in reaction of benzyl alcohol oxidation to benzaldehyde, which is known to be highly requested chemical with thousands of tons of annual production. Therefore "green" and selective route of production is highly desired. Developed PTI-LiCl was tested for selective photooxidation of benzyl alcohol to benzaldehyde, demonstrating precious conversion and selectivity rates—96.3% and 91.6%, respectively after 5 hours of UV irradiation. Detailed physical-chemical characterization revealed that PTI materials possessed more ordered and highly condensed structure which grant them improved photocatalytic properties in comparison to graphitic carbon nitride polymorph. Graphical abstract represents two different lines of materials which are known to be various polymorphs of carbon nitride studied comparatively in the present work. One of them is convenient graphitized carbon nitride which is prepared from precursors (melamine, urea or thiourea) via the simple thermal treatment. Another line of materials are prepared via thermal treatment in the eutectic mixture of molten salts. The later line of materials is more active in selective photocatalytic oxidation of benzyl alcohol.

The effect of cleaning with D2–(2–4) mol % N2 glow discharge plasma on the reflectivity of Mo(111) single-crystal mirrors is studied. The surface of each mirror is prepared by mechanical polishing with diamond pastes or diamond powder. Polishing of the mirrors is accompanied by the formation of a layer of material up to 3 microns thick, different in structure from the bulk metal. The peculiarity of this layer is a gradual improvement in its structure further away from the surface of the mirror and transition from an amorphous layer to a layer with nanoscale crystallites, and then a gradual transformation into the structure of an unbroken single crystal. When polishing, the diamond abrasive is pressed into the surface layer of the mirror. During the plasma-cleaning process, carbon particles pressed into the surface layer of the mirror initiate the development of negative roughness (pits or depressions). At the same time, a 5–10-nm layer of molybdenum nitride is formed. In disordered layers of the mirrors, the probability of the origination and growth of blisters is reduced. Aluminum is chosen as the metal that changes the total reflection coefficient of Mo. The use of a D2–N2 mixture to increase the rate of Al sputtering in the last stage of cleaning is replaced by plasma exposure in deuterium with $${\text{D}}_{3}^{ + }$$ ions, which initiates the dissociation of molybdenum nitride and the removal of nitrogen from the surface layer of the mirror. As a result of prolonged plasma exposure, the reflectivity of the mirrors polished with diamond paste increases to a steady-state value close to the reflection of the reference mirror.

Recently chamber inhibition emerged as a cost efficient and environmentally friendly type of vapor phase inhibition capable of protecting a metal surface from corrosion. In this work we study the structure and properties of a surface layer formed on copper after chamber treatment with 5-chloro-1,2,3-1H-benzotriazole (CBTA) whose protective effect significantly exceeds that of native copper oxide. Using a set of corrosion (recurrent moisture condensation conditions, outdoor tests), electrochemical (anodic potentiodynamic polarization, electrochemical impedance spectroscopy), and physical methods (Kelvin probe force microscopy, X-ray photoelectron spectroscopy), it was shown that the protective effect of CBTA was due to the formation of a thin layer of a complex compound with Cu(I) on the metal surface. With a growth in the chamber treatment temperature, the protective effect first increases due to an increase in the inhibitor vapor pressure and then falls at temperatures above 100 degrees C due to increased heterogeneity of the surface layer. (c) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

The features of the adsorption and passivating effect of sodium dodecylphosphonate (C12PNa2) on zinc, as well as the effect of electrode potential and presence of a surface oxide on them were studied. The possibility of zinc adsorption passivation by C12PNa2 with formation of nanolayers that inhibit zinc corrosion in a chloride-containing neutral solution and in a humid atmosphere was shown. The adsorption properties of C12PNa2 are most pronounced on an oxide-free zinc surface. The composition of the layers formed by C12PNa2 depends on the initial state of the surface and determines their protective ability.

The reaction of [Pt(NH3)4]Cl2 with NH4VO3 in alkaline solution in an autoclave at 190°C was studied. The solid autoclave thermolysis product was characterized by the methods of X-ray phase analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering, and elemental analysis. The product is represented by two phases: Pt and a Pt3V solid solution in the form of two types of particles of different morphology with a size less than 1 µm. The reaction stoichiometry {9[Pt(NH3)4]Cl2, 18NH4VO3, 18KOH} corresponds to the found amount of free ammonia (14NH3) formed under the selected conditions.

The effect of D2–N2 glow discharge plasma on the reflectivity of single-crystal Mo(111) mirrors is studied. The surface of each mirror is processed by mechanical polishing with diamond pastes to a roughness of hq = 5 nm. During polishing, abrasive particles are embedded in the surface layer of the mirror. Exposure to an ion fluence of 1.4 × 1024 m–2 leads to an increase in hq = 7 nm. After irradiation and the removal of a 30 nm-thick Mo layer the total reflection coefficient Rt in a 400–1000 nm region increases by 5–10% to a steady-state value (56–58)%. The increase in Rt may be caused by the preferential removal of carbon during the ion-sputtering process.

The possibility of subjecting aluminum to hydrophobization and superhydrophobization (SHP) with ethanol solutions of trialkoxysilanes and stearic acid is explored. It is shown that SHP coatings are highly effective in protecting Al against atmospheric corrosion. The thicknesses of surface SHP layers are determined via X-ray photoelectron spectroscopy and ellipsometry. The protective ability of SHP coatings is determined by polarization measurements and corrosion tests in a salt fog chamber.