scholarly journals Influence of Molybdenum and Tungsten on the Formation of Zirconium Oxide Coatings on a Steel Base

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 42
Author(s):  
Amangul Bold ◽  
Larissa Sassykova ◽  
Lidiya Fogel ◽  
Tigran Vagramyan ◽  
Aleksey Abrashov
Keyword(s):  
Corrosion Resistance ◽  
Zirconium Oxide ◽  
Deposition Temperature ◽  
Anodic Process ◽  
Electrochemical Studies ◽  
Optimal Conditions ◽  
Oxide Coatings ◽  
Adhesive Layers ◽  
Steel Base ◽  
Salt Fog

In this paper, we have developed conditions for the deposition of zirconium oxide coatings from solutions containing hexafluorozirconic acid as well as tungsten and molybdenum salts on a steel base. Based on electrochemical studies, it was shown that the addition of tungsten and molybdenum salts to the solution to deposit zirconium oxide coatings led to the inhibition of the anodic process of iron ionization. It was shown that the optimal conditions for the deposition of oxide-zirconium coatings on the surface of steel samples from a solution of 0.2 g/L Zr (IV) + 0.15 g/L W (VI) + 0.1 g/L Mo (VI) were a deposition temperature of 30 °C and time of 10 min. The thickness of the oxide-zirconium coatings formed under these conditions was 64.72 nm, the adhesion value was 3.17 MPa/s, and the corrosion resistance was 26 s according to Akimov’s drop method. The depth of corrosive penetration, determined in the salt fog chamber, did not exceed 2 mm after 240 h of testing, meeting the requirements for adhesive layers under the paintwork.

Characteristics of Phosphoric Acid Sealed Ceramic Oxide Coatings

1996 ◽  
Author(s):  
E. Kumpulainen ◽  
M. Vippola ◽  
P. Vuoristo ◽  
P. Sorsa ◽  
T. Mäntylä
Keyword(s):  
Corrosion Resistance ◽  
Phosphoric Acid ◽  
Zirconium Oxide ◽  
Ceramic Coatings ◽  
Atmospheric Plasma ◽  
Curing Temperature ◽  
Oxide Coatings ◽  
Heat Treated ◽  
Plasma Sprayed ◽  
Hardness Values

Abstract Plasma sprayed ceramic coatings usually have relatively high open porosity in order to provide a good corrosion protection. By using sealants the porosity values can be reduced. In this study atmospheric plasma sprayed (APS) aluminium oxide, chromium oxide and zirconium oxide coatings were sealed by a phosphoric acid treatment. After impregnation the coatings were heat treated at a curing temperature of 400°C. Phosphoric acid was found to react with the coating material during the heat treatment. Wear resistance was evaluated by rubber wheel abrasion tests and corrosion resistance by electrochemical potentio-dynamic polarization tests. Hardness values were also measured. Corrosion resistance and hardness values of sealed coatings were remarkable better in comparison to the unsealed coatings. Rubber wheel abrasion resistances of the sealed coatings were equal to those of Al2O3, ZTA, SiC and Si3N4 sintered ceramics.

scholarly journals Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1043
Author(s):  
Vitor Bonamigo Moreira ◽  
Anna Puiggalí-Jou ◽  
Emilio Jiménez-Piqué ◽  
Carlos Alemán ◽  
Alvaro Meneguzzi ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Active Sites ◽  
Modified Electrodes ◽  
Chemical Conversion ◽  
Ceramic Materials ◽  
Point Of View ◽  
Oxide Coatings ◽  
Alloying Element ◽  
Substrate Nature

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

The Effect of Sodium Silicate Concentration on the Properties of the Coating Formed on Pure Zirconium by Microarc Oxidation Coating Technique

2012 ◽  
Vol 445 ◽  
pp. 637-642 ◽  
Author(s):  
Y. Gencer ◽  
M. Tarakci ◽  
S. Cengiz ◽  
K.O. Gunduz
Keyword(s):  
Surface Roughness ◽  
Sodium Silicate ◽  
Zirconium Oxide ◽  
Microarc Oxidation ◽  
Phase Content ◽  
Oxide Coatings ◽  
Silicate Concentration ◽  
X Ray ◽  
Pure Zirconium ◽  
Scanning Electron

In this study, zirconium oxide coatings were formed on pure zirconium by microarc oxidation technique with the electrolytes containing KOH and different amounts of sodium silicate (0-40 gr/lt) for the same coating duration of 2 hours. The microstructure, surface roughness, phase content and chemical composition of the coatings were characterized by using scanning electron microscopy, profilometery and X-ray diffractometry. It was found that the coatings on surface of zirconium consist of monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrO2) phases and the addition and increasing sodium silicate concentration in the electrolyte increases amount of t-ZrO2 phase. The coatings were well adhered to Zr substrate with some cracks and porosities in the coating for all concentrations of sodium silicate. The coating thickness and surface roughness increased with sodium silicate concentration in the electrolyte. A glaze like Si rich structure and its increase with Si rate was evident in the outermost region of the coating.

scholarly journals Effect of Cooling Rate at the Eutectoid Transformation Temperature on the Corrosion Resistance of Zn-4Al Alloy

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1703
Author(s):  
Marzena M. Lachowicz ◽  
Robert Jasionowski
Keyword(s):  
Corrosion Resistance ◽  
Cooling Rate ◽  
Cast Alloy ◽  
Corrosion Current ◽  
Electrochemical Studies ◽  
Eutectoid Transformation ◽  
Nacl Solution ◽  
Α Phase ◽  
Initial Stage ◽  
Alloy Microstructure

The main purpose of this work was to experimentally determine the effect of the cooling rate during the eutectoid transformation on the corrosion resistance of a hypoeutectic Zn-4Al cast alloy in 5% NaCl solution. This was considered in relation to the alloy microstructure. For this purpose, metallographic and electrochemical studies were performed. It was found that the faster cooling promoted the formation of finer (α + η) eutectoid structures, which translated into a higher hardness and lower corrosion current density. In the initial stage of corrosion processes the eutectoid structure in the eutectic areas were attacked. At the further stages of corrosion development, the phase η was dissolved, and the α phase appears to be protected by the formation of corrosion products.

Double Interface Coatings on Silicon Carbide Fibers

2004 ◽  
Vol 843 ◽  
Author(s):  
Jun C. Nable ◽  
Shaneela Nosheen ◽  
Steven L. Suib ◽  
Francis S. Galasso ◽  
Michael A. Kmetz
Keyword(s):  
Silicon Carbide ◽  
Surface Coating ◽  
Zirconium Oxide ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Ceramic Fibers ◽  
Oxide Coatings ◽  
Silicon Carbide Fibers ◽  
Nitride Coatings

ABSTRACTInterface coatings on fibers are important in ceramic matrix composites. In addition to providing toughness, the interface coating must also protect the reinforcing ceramic fibers from corrosive degradation. A double interface coating has been applied onto silicon carbide fibers. The double interface coating is comprised of a combination of nitride and oxide coatings. Among the nitrides, boron nitride and titanium nitride were utilized. These nitrides were deposited by CVD. The metal oxides of choice were aluminum oxide and zirconium oxide which were applied onto the nitride coatings by MOCVD. The phases on the coated fibers were determined by XRD. The surface coating microstructures were observed by SEM. The effect of the coatings on the tensile strengths was determined by Instron tensile strength measurements.

Galvanised Sheets as Building Material

2014 ◽  
Vol 1020 ◽  
pp. 15-20 ◽  
Author(s):  
Janina Adamus ◽  
Monika Gierzyńska-Dolna ◽  
Wilhelm Gorecki ◽  
Piotr Lacki
Keyword(s):  
Corrosion Resistance ◽  
Civil Engineering ◽  
Zinc Coating ◽  
Key Factors ◽  
Forming Process ◽  
Factors Affecting ◽  
Steel Sheets ◽  
Steel Base ◽  
Structural Parts ◽  
The Relationship

Civil engineering uses steel as one of the basic structural materials. Sheets play an important role among the steel products. Although steel sheets are relatively cheap and have good mechanical and technological properties, low resistance against corrosion poses a fundamental weakness. A solution to this problem is the use of galvanised or organic-coated steel sheets. Galvanising can be carried out by hot dipping (single structural parts) or continuous galvanising: electrolytic and hot-dip galvanising (sheets and strips or long products, such as: wires or pipes).In the paper steel sheets used in the civil engineering as structural parts or wall and roof cladding are discussed. A special attention is paid to corrosion resistance of the steel sheets. Some results of corrosion tests is presented. The tests were aimed at determination the corrosion resistance of hot-dip and electrolytic galvanised sheets. The influence of the galvanising technology and the relationship between the degree of material deformation and susceptibility to corrosion are given. Coating thickness and kind of the applied galvanising technology is pointed as the key factors affecting the corrosion resistance of galvanised sheets. It is highlighted that during the forming process of galvanised sheets (bending, sheet-metal forming) the zinc coating deforms more than the steel base, so its thickness decreases, and therefore the corrosion resistance of the final product decreases, too.

Characterization of the porosity of thin zirconium oxide coatings prepared at low temperatures

2009 ◽  
Vol 517 (6) ◽  
pp. 1967-1969 ◽  
Author(s):  
R. Ugas-Carrión ◽  
F. Sittner ◽  
C.J. Ochs ◽  
S. Flege ◽  
W. Ensinger
Keyword(s):  
Low Temperatures ◽  
Zirconium Oxide ◽  
Oxide Coatings
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