Hot corrosion properties of composite coatings in the presence of NaCl at 700 and 900°C

2013 ◽  
Vol 70 ◽  
pp. 29-36 ◽  
Author(s):  
Jun Ma ◽  
Su Meng Jiang ◽  
Jun Gong ◽  
Chao Sun
Keyword(s):  
Hot Corrosion ◽  
Composite Coatings ◽  
Corrosion Properties

Electroless Ni–P–(nano-MoS2) composite coatings and their corrosion properties

2009 ◽  
Vol 25 (5) ◽  
pp. 361-366 ◽  
Author(s):  
X. G. Hu ◽  
W. J. Cai ◽  
Y. F. Xu ◽  
J. C. Wan ◽  
X. J. Sun
Keyword(s):  
Composite Coatings ◽  
Corrosion Properties ◽  
Electroless Ni

Composite Coatings Formed on PEO Pretreated MA8 Magnesium Alloy in Aqueous Suspension of PTFE

2021 ◽  
Vol 885 ◽  
pp. 95-102
Author(s):  
Evgeny A. Belov ◽  
Konstantine V. Nadaraia ◽  
Dmitry V. Mashtalyar ◽  
Igor M. Imshinetsky ◽  
Andrey P. German ◽  
...  
Keyword(s):  
Composite Coatings ◽  
Aqueous Suspension ◽  
Corrosion Current ◽  
Composite Polymer ◽  
Corrosion Properties ◽  
Composite Layers ◽  
Electrolytic Oxidation ◽  
Subsequent Application ◽  
Plasma Electrolytic ◽  
Scratch Tests

The paper presents results of the composite polymer-containing layers formation by plasma electrolytic oxidation (PEO) with subsequent application of the superdispersed polytetrafluoroethylene (SPTFE) aqueous suspension. The corrosion properties and adhesion of coatings have been investigated using potentiodynamic polarization and scratch tests. Incorporation of SPTFE decreased the corrosion current density for composite layers by more than 3 orders of magnitude in comparison with the base PEO-coating and increased the coatings adhesion by 30 %.

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

scholarly journals Comparative studies of microstructural, tribological and corrosion properties of Zn-TiO2 and Zn-TiO2-WO3 nano-composite coatings

2017 ◽  
Vol 7 ◽  
pp. 3222-3229 ◽  
Author(s):  
A.A. Daniyan ◽  
L.E. Umoru ◽  
A.P.I. Popoola ◽  
O.S.I. Fayomi
Keyword(s):  
Comparative Studies ◽  
Composite Coatings ◽  
Corrosion Properties ◽  
Nano Composite

scholarly journals Features of CЕС technology for eco- and energytechnologies

2021 ◽  
pp. 89-96
Author(s):  
Mykola Sakhnenko ◽  
Hanna Karakurkchi ◽  
Tetiana Nenastina ◽  
Irina Yermolenko ◽  
Alla Korohodska
Keyword(s):  
Technological Process ◽  
Composite Coatings ◽  
Functional Materials ◽  
Modular Approach ◽  
Properties Of Coatings ◽  
Corrosion Properties ◽  
Energy Characteristics ◽  
Flexible Control ◽  
Energy Technologies ◽  
Time And Energy

Based on the analysis of the peculiarities of CEC formation, it is shown that their production and application is one of the world trends in functional electroplating and allows to solve a number of practical problems, in particular in the field of eco- and energy technologies. The deposition of polyfunctional CECs of cobalt with refractory metals was carried out from citrate-pyrophosphate electrolytes in galvanostatic and pulsed modes. The obtained composite coatings have a complex of increased mechanical and anti-corrosion properties, catalytic and photocatalytic activity, which determines the prospects for the use of the obtained thin-film materials in many industries. It is shown that the processes of formation of such multicomponent systems are very complex, a separate problem that needs to be solved is the organization of the technological process of CEC adapted to production needs. The scheme of organization of technological process on the basis of the modular approach which is based on results of complex researches of influence of quantitative characteristics of working electrolytes and modes of electrolysis on structure and properties of the synthesized coverings is developed. The generalized scheme of CEC technology reflects the sequence of generally accepted processes and operations in electrochemical production with the possibility of applying the modular principle of organization of galvanic sites and shops. Variability of technological schemes provides flexible control of the composition and properties of coatings by changing the time and energy characteristics of electrodeposition with insignificant adjustment of the quantitative and qualitative composition of electrolytes. The developed modular approach in the organization of technological process can be used as a basis for other electrochemical technologies of synthesis of functional materials.

Study of Hardness and Corrosion Resistance of Electroless Ni-P-TiO2 Composite Coatings

2017 ◽  
pp. 1303-1326
Author(s):  
Prasanna Gadhari ◽  
Prasanta Sahoo
Keyword(s):  
Corrosion Resistance ◽  
Annealing Temperature ◽  
Composite Coatings ◽  
Electroless Nickel ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
Nickel Coatings ◽  
Nodular Structure ◽  
Grey Relational ◽  
Electroless Ni

Electroless nickel coatings are widely popular in various industrial sectors due to their excellent tribological properties. The present study considers optimization of coating parameters along with annealing temperature to improve microhardness and corrosion resistance of Ni-P-TiO2 composite coatings. Grey relational analysis is used to find out the optimal combination of coating parameters. From the analysis, it is confirmed that annealing temperature of the coating has the most significant effect and amount of titanium particles in the coating has some significant effect on corrosion properties of the coating. The same trend is observed in case of combined study of corrosion behavior and microhardness. The surface morphology, phase transformation and the chemical composition are examined using scanning electron microscopy, X-ray diffraction analysis and energy dispersive analysis respectively. The Ni-P-TiO2 composite coating revealed nodular structure with almost uniform distribution of titanium particles and it turns in to crystalline structure after heat treatment.

Performance of Thermal Insulation Reflective Composite Coatings

2011 ◽  
Vol 239-242 ◽  
pp. 1771-1774 ◽  
Author(s):  
Meng Qiu Jia ◽  
Yu Hong Jin
Keyword(s):  
Aqueous Solution ◽  
Thermal Insulation ◽  
Heat Insulation ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Insulation Property ◽  
Corrosion Properties ◽  
Rutile Titanium Dioxide ◽  
Insulation Performance ◽  
Good Heat

Reflective topcoat and thermal insulation mid-coat composite coatings system was used in this work. The effect of the content of the hollow glass micro-beads and rutile titanium dioxide on the heat insulation performance and the reflectivity of the coatings were investigated, respectively. The heat insulation performance and the reflectivity of the thermal insulation reflective composite coatings (TIRCCs) were characterized by self-prepared experimental device. The results showed the good heat insulation property, and the insulated temperature reached 12-15°C, and the reflectivity was up to 95%. The anti-corrosion and anti-penetration of the TIRCCs were studied by electrochemical impedance spectroscopy (EIS) technique. The results showed that the resistance of the TIRCCs still be maintained at 108Ω·cm2 after 30 days in the 3.5% aqueous solution of sodium chloride. So The TIRCCs can be used on the surface of the steal structure for decreasing the temperature and enhancing anti-corrosion properties.

Influence of the Organic Additions on Structure, Corrosion Resistance and Tribological Properties of Ni/Al2O3 Composite Coatings

2013 ◽  
Vol 765 ◽  
pp. 663-667
Author(s):  
Marek Nowak ◽  
Mieczysław Opyrchał ◽  
Sonia Boczkal ◽  
Janusz Żelechowski
Keyword(s):  
Corrosion Resistance ◽  
Tribological Properties ◽  
Composite Coatings ◽  
Electrochemical Behaviour ◽  
Wear Test ◽  
Standard Test ◽  
Properties Of Coatings ◽  
Corrosion Properties ◽  
X Ray ◽  
Xrd Techniques

Composite Ni/Al2O3 coatings were electrochemically deposited from a Watts bath modified with the organic additions of dioctyl sulphosuccinate sodium salt C20H37NaO7S–(DSS) and 2,3-dihydroxy-1,2 benzisothiazol-3-one 1,1-dioxide C7H5NO3–(LSA). The effect of different amount (50 and 100 g/l) of Al2O3 powder and organic additions on microstructure, microhardness, corrosion resistance and tribological properties was investigated. The coatings were examined by optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) techniques. The electrochemical behaviour of the coatings in corrosive solutions (1 M NaCl and 1 M Na2SO4) was investigated by potentiodynamic polarisation. The tribological properties were investigated by the Taber abrasive wear test, a standard test often applied in industrial practice. The results show that Al2O3 particles are uniformly distributed in the composite coatings compared with coatings without organic additions. The addition of organic compounds also reduced the size of the forming nickel crystallites and improved the tribological and corrosion properties of coatings containing the dispersed hard particles of Al2O3 added in an amount of 50 g/l and the addition of organic LSA and DSS compounds.

Microstructure and Hot Corrosion Properties of Laser Cladding of a Co-Base Alloy on the Leaf Surface of Gas Turbine

2011 ◽  
Vol 299-300 ◽  
pp. 183-187
Author(s):  
Song Zhang ◽  
Gong You Zhou ◽  
Fang Hu ◽  
Chun Hua Zhang ◽  
Mao Cai Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Gas Turbine ◽  
Hot Corrosion ◽  
Carbon Dioxide Laser ◽  
Base Alloy ◽  
Stainless Steel Surface ◽  
Protective Oxide ◽  
Corrosion Properties ◽  
Protective Oxide Film

The temperatures inside the gas turbine reach up to 1000°C, alloys used for gas turbine components must be oxidation, and corrosion resistant, and stable in structure under high temperature circumstances. A Co-based alloy was cladded on the 1Cr18Ni9Ti stainless steel surface using a high power carbon dioxide laser. The microstructure evolution and hot corrosion properties of samples in 75%Na2SO4+25%NaCl saline were investigated. The results show that the microstructures of the cladded layer is fine, and the hot corrosion resistance of the cladded layer was significantly improved because of the formation of a protective oxide film of CoO and CoO•Cr2O3. Under high temperature corrosive atmosphere, the high content of Co promoted the formation of the protective oxide film. The refinement of dendritic structures and the formation of Co-based alloy oxides lower the penetration rate of the sulphur ions that induce the intergranular corrosion.

Sign in / Sign up

Export Citation Format

Share Document