Corrosion investigation and evaluation of mechanical and structural properties of powder coatings

2016 ◽  
Vol 7 (1) ◽  
pp. 2-24 ◽  
Author(s):  
Elias P. Koumoulos ◽  
Ioannis A Kartsonakis ◽  
G Vlachakis ◽  
M Vlachakis ◽  
Costas A. Charitidis
Keyword(s):  
Aluminium Alloy ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Spray Coating ◽  
Powder Coatings ◽  
Properties Of Coatings ◽  
Content Type ◽  
X Ray ◽  
Nanomechanical Properties ◽  
Corrosion Investigation

Purpose – The purpose of this paper is to deal with the study of properties of anticorrosion powder based coatings on aluminium alloy 2024. Design/methodology/approach – The powder based coatings were applied to the AA2024 substrates using a spray coating technique. All the substrates were covered with a primer prior the powder based coatings. The morphology and composition of the coatings was examined by scanning electron microscopy and energy dispersive X-ray analysis, respectively. Studies on the corrosion resistance of these coatings were made using electrochemical impedance spectroscopy. Findings – The results reveal that the powder based coatings together with the primer coatings demonstrate improved corrosion protection to AA2024 after exposure to corrosive environment. Moreover, the primer coating is mechanically enhanced compared to the top coating, while the top coating exhibited significant resistance to wear. Originality/value – The paper deals with the evaluation of corrosion and nanomechanical properties of coatings applied on aluminium alloy.

Synergistic effect of chloride and NO2 on the atmospheric corrosion of bronze

2009 ◽  
Vol 56 (6) ◽  
pp. 299-305 ◽  
Author(s):  
Xia Cao ◽  
Ning Wang ◽  
Ning Liu
Keyword(s):  
Synergistic Effect ◽  
Design Methodology ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
Content Type ◽  
X Ray ◽  
Corrosion Kinetics ◽  
Tension Tests

PurposeThe purpose of this paper is to investigate the effect of chloride along with NO2 on the atmospheric corrosion of bronze using exposure tests.Design/methodology/approachSurface tension tests and electrochemical impedance measurements together with scanning electron microscopy (SEM) with energy dispersive atomic X‐ray, and X‐ray diffraction are used to characterize the corrosion behavior.FindingsThe results of the weight loss measurements show that the whole corrosion kinetics can be described approximately by: ΔW=atb; the synergistic effect of chloride and NO2 is observed clearly, though no nitrate existed in the corrosion products.Originality/valueA new catalyst theory has been suggested in this paper, i.e. that NO2 acts as a catalyst during the corrosion process when significant quantities of chloride also are present.

Structural, electrochemical and mechanical studies of ultrasonic irradiation enhanced electroplating Ni coating

2018 ◽  
Vol 65 (4) ◽  
pp. 333-339 ◽  
Author(s):  
Chaolei Ban ◽  
Shuqin Zhu ◽  
Jie Ma ◽  
Fangreng Wang ◽  
Zhengfeng Jia ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Ultrasonic Irradiation ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Mechanical Studies

Purpose Ni coating was electroplated on carbon steel substrate to protect carbon steel. Design/methodology/approach During electroplating, the ultrasonic irradiation (UI) (1 kHz) action was in situ used with different frequency. The influence of UI on the microstructure, mechanical and electrochemical performance of the coating was studied with scanning electron microscopy, X-ray diffraction, microhardness measurement, polarization curves and electrochemical impedance spectroscopy. Findings The results show that comparing that without UI imposition, UI during electroplating can refine the coating grain and decrease the micro-pores in the coating, resulting in improvement of the coating corrosion and hardness. Originality/value The imposition of UI action during electroplating Ni coating can remove intrinsic pores in the coating and compact the coating. The potential bimetallic cell between substrate and plating layer can be insulated to enhance the corrosion resistance of Ni coating. The imposition of UI action during electroplating Ni coating can refine Ni coating grain size and improve the coating haredness.

The influence of hexamethylenetetramine on the structure and corrosion resistance of phosphate coating on AZ31 magnesium alloy

2016 ◽  
Vol 63 (3) ◽  
pp. 161-165 ◽  
Author(s):  
Jiansan Li ◽  
Yali Li ◽  
Yanqin Chen ◽  
Jiawei Sun ◽  
Chunxiao Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Design Methodology ◽  
Energy Dispersive Spectrometry ◽  
Electrochemical Impedance ◽  
Phosphate Coating ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Phosphate Coatings

Purpose This paper aims to report the influence of hexamethylenetetramine (HMTA) on phosphate coatings formed on AZ31 magnesium alloys. Design/methodology/approach These phosphate coatings were obtained by immersing magnesium alloys in phosphate baths with HMTA. The morphology and composition of the phosphate coatings were investigated via scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Findings The phosphate coatings were mainly composed of CaHPO4·2H2O. The HMTA concentration in the phosphate bath influenced the crystallization and corrosion resistance of the phosphate coating. Originality/value The polarization curve shows that the anti-corrosion qualities of the phosphate coating were optimal when the HMTA concentration was 1.0 g/L in the phosphate bath. Electrochemical impedance spectroscopy (EIS) shows that the electrochemical impedances increased gradually when the HMTA concentration varied from 1.0 to 3.0 g/L.

Dependence of hydrogen embrittlement on annealing time in medium-Mn steels

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Juanping Xu ◽  
Jinxu Li ◽  
Zheng Wang ◽  
Hao Fu ◽  
Ming Wu
Keyword(s):  
Hydrogen Embrittlement ◽  
Annealing Time ◽  
Martensite Transformation ◽  
Design Methodology ◽  
Warm Rolling ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
Content Type ◽  
X Ray ◽  
Two Samples

Purpose The purpose of this paper is to investigate the effect of the soft annealing time on the microstructure and hydrogen embrittlement (HE) of Fe-0.22C-11.54Mn-2.05Al steels. Design/methodology/approach Steels A and B with different morphologies were prepared by cold rolling after warm rolling, long/short softening annealing and finally annealing at 700 °C for 30 min. Uncharged and charged samples were subjected to tensile, and HE behavior was studied by electron backscattered diffraction, scanning electron microscopy and X-ray diffraction. Findings The two samples exhibited similar tensile strengths. The homogeneous equiaxed microstructure of steel B was found to be more conducive to relieve its HE sensitivity. Steel A exhibited bimodal-grained microstructures – blocky and lath. The formation of crack in the blocky grains of steel A resulted in a significant reduction in its plasticity and tensile strength. Originality/value The high HE susceptibility of steel A is mainly connected with the inhomogeneity of martensite transformation.

Corrosion inhibition of N80 steel in 10% HCl + 8% HBF4solution

2019 ◽  
Vol 66 (1) ◽  
pp. 1-10
Author(s):  
Juan Du ◽  
Yuning He ◽  
Pingli Liu ◽  
Yigang Liu ◽  
Xianghai Meng ◽  
...  
Keyword(s):  
Corrosion Inhibition ◽  
Design Methodology ◽  
X Ray Diffraction ◽  
Corrosion Morphology ◽  
Content Type ◽  
X Ray ◽  
N80 Steel ◽  
Corrosion Reaction ◽  
Hydrolysis Of ◽  
Scanning Electron

PurposeThis paper aims to analyze the corrosion and corrosion inhibition of N80 in 10 per cent HCl + 8 per cent fluoroboric acid (HBF4) solution for acidizing operation.Design/methodology/approachThe corrosion rate, kinetic parameters (Ea, A) and thermodynamic parameters (ΔH, ΔS) of N80 steel in fresh acid and spent acid, 10 per cent HCl + 8 per cent HBF4, 10 per cent HCl and 8 per cent HBF4solutions were calculated through immersion tests. The corrosion and inhibition properties were studied through X-ray diffraction and electrochemical measurements. The corrosion morphology of the corrosion product was examined by scanning electron microscopy (SEM).FindingsThe results demonstrated that the spent acid was the main cause of acidification corrosion, and the HBF4would cause serious corrosion to N80 steel. The results showed that the N80 steel was more seriously corroded in the spent acid than in fresh acid, and the hydrolysis of HBF4accelerates the dissolution process of N80 steel anode to control the corrosion reaction. The results showed that the acidification will definitely cause serious corrosion to the oil tube; therefore, necessary anti-corrosion measures must be taken in the acidification process.Originality/valueThe results showed that acidizing the formation with 10 per cent HCl + 8 per cent HBF4will definitely cause serious corrosion to the oil tube, especially when the spent acid flows back. Therefore, necessary anti-corrosion measures must be taken in the acidification process, especially in the spent acid flowback stage.

Corrosion behavior of in situ (TiC-TiB2)p/AZ91 magnesium matrix composites in Harrison solution

2014 ◽  
Vol 61 (5) ◽  
pp. 319-327 ◽  
Author(s):  
Mohamed Gobara ◽  
Mohamed Shamekh
Keyword(s):  
Mechanical Properties ◽  
Corrosion Behavior ◽  
Matrix Composite ◽  
Electrochemical Impedance ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Content Type ◽  
X Ray ◽  
Az91 Magnesium

Purpose – This paper aims to study both the mechanical properties and the corrosion behavior of the synthesized in situ (TiC-TiB2) particulates/AZ91 magnesium matrix composite and compare the results with that of the conventional AZ91D alloy. Design/methodology/approach – Scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were used to study the surface morphology and crystalline structure. Mechanical compression tests were used to investigate the mechanical performance according to ASTM E9-89a. The corrosion behavior of the synthesized magnesium alloy was examined using both electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques in dilute Harrison solutions. Findings – The microstructure of the Mg composite showed a uniform distribution of reinforcing phases. Also, the reinforcing phases were formed without residual intermediate phases. The addition of titanium and boron carbides not only enhanced the mechanical properties of the matrix but also improve its corrosion behavior. Originality/value – This is the first time that magnesium matrix composite has been to synthesized with TiC and TiB2 particulates starting from starting from Ti and B carbides powder without adding aluminium using practical and low-cost technique (in situ reactive infiltration technique). This paper studies the corrosion behavior of synthesized Mg matrix in dilute Harrison solution and compares the results with that of conventional AZ91D.

Applicability of EIS for evaluation of corrosion resistance of aluminum flakes

2016 ◽  
Vol 63 (5) ◽  
pp. 355-359
Author(s):  
Naghmeh Amirshaqaqi ◽  
Mehdi Salami-Kalajahi ◽  
Mohammad Mahdavian
Keyword(s):  
Corrosion Resistance ◽  
Conventional Method ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Quantitative Estimation ◽  
Surface Modifications ◽  
Organic Coatings ◽  
Nacl Solution ◽  
Content Type ◽  
Alkaline Conditions

Purpose The conventional method for evaluation of corrosion resistance of aluminum flakes is based on the volume of evolved hydrogen in acidic and basic environments. This study aims to introduce electrochemical impedance spectroscopy (EIS) as a method to evaluate corrosion resistance of aluminum flakes. Design/methodology/approach Aluminum flakes with different surface modifications were compressed to build a disk. Then, the disks were examined by EIS in NaCl solution. Also, the corrosion resistance of the flakes was evaluated by the conventional method. Findings The results revealed applicability of EIS for evaluation of corrosion resistance of aluminum flakes. Originality/value Application of EIS to evaluate corrosion resistance of aluminum flakes is novel. As it can provide fast, reliable and quantitative estimation of the corrosion resistance of the aluminum flakes in the 3.5 per cent NaCl solution. This medium is highly encountered for the aluminum flakes used in organic coatings, that is why test in NaCl solution is more convenient compared to the conventional methods using acid and alkaline conditions.

Corrosion protective properties of coatings doped with inhibitors

2014 ◽  
Vol 61 (6) ◽  
pp. 416-422 ◽  
Author(s):  
Mansoureh Parsa ◽  
Seyed Mohammad Ali Hosseini ◽  
Zahra Hassani ◽  
Effat Jamalizadeh
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Titania Nanoparticles ◽  
Self Healing ◽  
Properties Of Coatings ◽  
Ethylene Imine ◽  
Protective Properties ◽  
Content Type

Purpose – The purpose of this paper was to study the corrosion resistance of water-based sol-gel coatings containing titania nanoparticles doped with organic inhibitors for corrosion protection of AA2024 alloy. Design/methodology/approach – The coatings were obtained using tetraethylorthosilicate, 3-glycidoxypropyltrimethoxysilane, titanium (IV) tetrapropoxide and poly(ethylene imine) polymer as cross-linking agents. As corrosions inhibitors, 2-mercaptobenzoxazole and salicylaldoxime were incorporated into the sol-gel for the improvement of the corrosion resistance. The corrosion protection performance of coatings was studied using the potentiodynamic scan and the electrochemical impedance spectroscopy (EIS) methods. Atomic force microscopy was used to investigate surface morphology of the coatings. Findings – The results indicated that doping the sol-gel coatings with inhibitors leads to improvement of the corrosion protection. The comparison of doped coatings confirmed that corrosion protection performance of the sol-gel coatings doped with 2-mercaptobenzoxazole was better than for the sol-gel coatings doped with salicylaldoxime. Also the EIS results verified self-healing effects for the sol-gel coatings doped with 2-mercaptobenzoxazole. Originality/value – This paper indicates 2-mercaptobenzoxazole and salicylaldoxime can be added as corrosion inhibitors to sol-gel coatings to improve their corrosion protective properties for AA2024 alloy.

Effects of SO42− concentration on corrosion behaviour of carbon steels

2015 ◽  
Vol 62 (5) ◽  
pp. 322-326 ◽  
Author(s):  
Zhiping Zhu ◽  
Xiaocui Jiao ◽  
Xueying Tang ◽  
Haiwei Lu
Keyword(s):  
Water Chemistry ◽  
Pitting Corrosion ◽  
Design Methodology ◽  
Competitive Adsorption ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Carbon Steels ◽  
Boiler Water ◽  
Content Type ◽  
Condition Solution

Purpose – The purpose of this paper was to investigate the effects of SO42− concentration on the corrosion behaviour of T23 and T12 steels in simulated water chemistry condition solution of 600 MW fossil-fired power boilers. Design/methodology/approach – The influence and mechanism of SO42− ions on the pitting corrosion of T23 and T12 steels in simulated oxygenated treatment water chemistry solution was studied using electrochemical potentiodynamic polarization scans and electrochemical impedance spectroscopy. Findings – The results showed that T23 and T12 were susceptible to pitting corrosion in the simulated solution with full SO42− concentration for the competitive adsorption of OH− and SO42− on the surface of steels. The pitting sensitivity of the steels improved with increasing SO42− concentration. The corrosion resistance for SO42− of T23 was stronger than that for T12. Originality/value – This study is an attempt to provide direction for regulating the concentration of SO42− in boiler water and for selecting the material for boiler water wall tubes.

Influence of firing profile on microstructural and dielectric properties of LTCC substrates

2017 ◽  
Vol 34 (3) ◽  
pp. 127-130 ◽  
Author(s):  
Alena Pietrikova ◽  
Tibor Rovensky ◽  
Juraj Durisin ◽  
Igor Vehec ◽  
Ondrej Kovac
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dwell Time ◽  
Design Methodology ◽  
Peak Temperature ◽  
Dielectric Losses ◽  
Sintering Process ◽  
Alpha Radiation ◽  
Content Type ◽  
X Ray

Purpose The purpose of this paper is to analyse the influence of various firing profiles on microstructural and dielectric properties of low-temperature, co-fired ceramic (LTCC) substrates in a GHz frequency range. According these analyses, sintering process can be controlled and modified to achieve better performance of devices fabricated from LTCC substrates. Design/methodology/approach Samples from LTCC substrates GreenTape 951 and GreenTape 9K7 were sintered by four firing profiles. Basic firing profile recommended by the manufacturer was modified by increasing the peak temperature or the dwell time at the peak temperature. The influence of firing profile on microstructural properties was analysed according to measurements by X-ray diffractometer (application of the Cu K-alpha radiation and the Bragg-Brentano method), and the influence on dielectric properties (dielectric constant and dielectric losses) was analysed according to measurements by split cylinder resonator method at 9.7 and 12.5 GHz. Findings Rising of the peak temperature or extension of dwell time at this temperature has influence on all analysed properties of LTCC substrates. Size of crystallites can be changed by modification of firing profile as well as microdeformation. In addition, dielectric properties can be changed too by modification of the firing profile. Correlation between microdeformation and dielectric losses was observed. Originality/value The novelty of this work lies in finding the mutual relationship between changes in microstructural (size of grains and microdeformation) and dielectric properties (dielectric constant and dielectric losses) caused by different firing profiles.

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