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Publications (10 of 31) Show all publications
Maryam, E., Payandeh, M., Deflorian, F., Jarfors, A. E. .. & Zanella, C. (2018). Effect of Segregation and Surface Condition on Corrosion of Rheo-HPDC Al–Si Alloys. Metals, 8(4), Article ID 209.
Open this publication in new window or tab >>Effect of Segregation and Surface Condition on Corrosion of Rheo-HPDC Al–Si Alloys
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2018 (English)In: Metals, Vol. 8, no 4, article id 209Article in journal (Refereed) Published
Abstract [en]

Corrosion properties of two Al–Si alloys processed by Rheo-high pressure die cast (HPDC) method were examined using polarization and electrochemical impedance spectroscopy (EIS) techniques on as-cast and ground surfaces. The effects of the silicon content, transverse and longitudinal macrosegregation on the corrosion resistance of the alloys were determined. Microstructural studies revealed that samples from different positions contain different fractions of solid and liquid parts of the initial slurry. Electrochemical behavior of as-cast, ground surface, and bulk material was shown to be different due to the presence of a segregated skin layer and surface quality.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
Al–Si alloys, rheocasting, HPDC, electrochemical evaluation
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:hj:diva-39065 (URN)10.3390/met8040209 (DOI)000434882800012 ()2-s2.0-85044734700 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Funder
Knowledge Foundation, 20100280
Available from: 2018-03-28 Created: 2018-03-28 Last updated: 2018-07-05Bibliographically approved
Leisner, P., Zanella, C., Belov, I., Edström, C., Sandulache, G. & Hansal, W. E. (2017). Control of silver throwing power by pulse reverse electroplating. Transactions of the Institute of Metal Finishing, 95(1), 25-30
Open this publication in new window or tab >>Control of silver throwing power by pulse reverse electroplating
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2017 (English)In: Transactions of the Institute of Metal Finishing, ISSN 0020-2967, E-ISSN 1745-9192, Vol. 95, no 1, p. 25-30Article in journal (Refereed) Published
Abstract [en]

The influence of electroplating parameters on throwing power (TP) is studied in additive-free silver cyanide solutions under direct current and pulse reverse electroplating conditions. It is found that the best TP is obtained when no agitation of the electrolyte is applied. The most important parameters for controlling the TP are the cathodic current density, the anodic to cathodic charge ratio, and the ratio between the anodic and cathodic current densities. Guidelines for process optimisation are given.

Place, publisher, year, edition, pages
Taylor & Francis, 2017
Keywords
Agitation, Pulse reverse electrodeposition, Silver, Throwing power, Electrolytes, Electroplating, Optimization, Cathodic charge, Cathodic current density, Direct current, Process optimisation, Pulse-reverse electrodeposition, Silver cyanide, Electroplating solutions
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-35017 (URN)10.1080/00202967.2017.1260895 (DOI)000394497000007 ()2-s2.0-85009956051 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Funder
VINNOVA, 2013-01883
Available from: 2017-02-06 Created: 2017-02-06 Last updated: 2017-07-06Bibliographically approved
Eslami, M., Fedel, M., Speranza, G., Deflorian, F. & Zanella, C. (2017). Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy. Journal of the Electrochemical Society, 164(9), C581-C590
Open this publication in new window or tab >>Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 9, p. C581-C590Article in journal (Refereed) Published
Abstract [en]

Cerium-based conversion coatings were deposited on high pressure die cast (HPDC) Al-Si alloys using an immersion method. Hydrogen peroxide and sodium chloride were added to the conversion solution to accelerate the coating formation and to understand its formation mechanism. These studies showed that the deposition of cerium hydroxide/ oxide conversion layer starts from iron-rich intermetallic particles, which are located inside the eutectic region and then the coating growth continues to cover the entire alloy surface. This phenomenon passivates the active interfaces between iron-rich intermetallic particles and/ or the eutectic silicon phase and the aluminum matrix, which are prone to localized corrosion in chloride ions containing environments. Accordingly, values of the total impedance in EIS measurements significantly increased for the treated substrates. Morphologies of the conversion coatings and the oxidation state of cerium compounds were found to be dependent on the composition of the solution and the presence of chloride ions and/ or hydrogen peroxide. Aluminum alloy with higher silicon content showed a more active surface during immersion in the conversion solution. This makes it more difficult to be treated using aggressive conversion solutions. 

Place, publisher, year, edition, pages
Electrochemical Society, 2017
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38179 (URN)10.1149/2.1511709jes (DOI)000413256400034 ()JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2017-12-15Bibliographically approved
Ahmadkhaniha, D., Huang, Y., Jaskari, M., Järvenpää, A., Heydarzadeh Sohi, M., Zanella, C., . . . Langdon, T. (2017). Effect of high-pressure torsion on microstructure, mechanical properties and corrosion resistance of cast pure Mg. In: : . Paper presented at 6 th International Biennial Conference on Ultrafine Grained and Nano-structured Materials (UFGNSM 2017), 12th-13th November, 2017, Kish Island, Iran.
Open this publication in new window or tab >>Effect of high-pressure torsion on microstructure, mechanical properties and corrosion resistance of cast pure Mg
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2017 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

High-pressure torsion (HPT) processing was applied to cast pure Mg pieces and its effects on microstructure, hardness and tensile properties as well as corrosion resistance were evaluated. The microstructure of the processed samples was examined by electron backscatter diffraction (EBSD) and the mechanical properties were determined by microhardness and tensile tests. Corrosion resistance of the samples was studied via electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results showed that HPT refined the grain size of Mg very effectively from millimeters in the cast structure to a few micrometers homogeneously through the thickness and created a basal texture on the surface. One or five turns of HPT produced no significant difference in the grain size of the processed Mg but the hardness was a maximum after one turn. The yield strength of the cast Mg was increased by seven times whereas the corrosion resistance was not affected by the HPT processing.

Keywords
Corrosion resistance, Grain size, Hardness, High-pressure torsion, Mg, Tensile strength, Texture
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:hj:diva-38704 (URN)
Conference
6 th International Biennial Conference on Ultrafine Grained and Nano-structured Materials (UFGNSM 2017), 12th-13th November, 2017, Kish Island, Iran
Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-02-02Bibliographically approved
Zhu, B., Fedel, M., Andersson, N.-E., Leisner, P., Deflorian, F. & Zanella, C. (2017). Effect of Si content and morphology on corrosion resistance of anodized cast Al-Si alloys. Journal of the Electrochemical Society, 164(7), C435-C441
Open this publication in new window or tab >>Effect of Si content and morphology on corrosion resistance of anodized cast Al-Si alloys
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 7, p. C435-C441Article in journal (Refereed) Published
Abstract [en]

This paper investigates the influence of Si content and Si particle morphology on the corrosion protection of anodized oxide layers on Al-Si alloys. Two Al alloys with low Si concentrations (2.43 wt-% and 5.45 wt-%, respectively) were studied and compared with 6082-T6 via electrochemical impedance spectroscopy (EIS) in 3 wt-% NaCl solution prior to oxide layer sealing. Si particles were also modified by the addition of Sr to study the influence of Si particle morphology on the corrosion protection of the oxide layer. The EIS showed that the corrosion protection provided by the oxide layer on Al-Si alloys is significantly affected by the presence of Si particles. Si particles make the oxide layer locally thinner and more defective in the eutectic region, thereby increasing the ease of substrate corrosion attack. However, the addition of Sr can improve the corrosion protection of anodized Al-Si alloys significantly. Furthermore, it was proved that higher Si level influences negatively the anodized oxide corrosion protection due to the higher amount of cracks and defects, but Sr modification is efficient in preventing this negative effect.

Place, publisher, year, edition, pages
The Electrochemical Society, 2017
Keywords
cast Al-Si alloys, anodising, EIS, 3D tomography
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-35095 (URN)10.1149/2.1631707jes (DOI)000404397300077 ()2-s2.0-85020855659 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Note

Part of licentiate thesis in its submitted form.

Available from: 2017-02-17 Created: 2017-02-17 Last updated: 2017-09-13Bibliographically approved
Ahmadkhaniha, D., Pinate, S., Leisner, P. & Zanella, C. (2017). Electrodeposition of Ni high P composite coatings containing nano and submicro ceramic particles. In: : . Paper presented at EUROCORR 2017, Annual Congress of the European Federation of Corrosion | 20th International Corrosion Congress & Process Safety Congress 2017, September 3–7, 2017, Czech Republic.
Open this publication in new window or tab >>Electrodeposition of Ni high P composite coatings containing nano and submicro ceramic particles
2017 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

In this study, electrodeposition of Ni-P composite coatings has been carried out to investigate the possibility of replacing hard chromium coatings. Therefore, electrodeposition of Ni-P based composite coating with different SiC particle size (50 nm, 100 nm and 500 nm) or B4C (500 nm) was performed. The coating’s composition was evaluated by energy dispersive spectroscopy (EDS), microhardness of the coatings was measured by Vickers indentor and polarization measurements were carried out to study the corrosion behavior of the coatings. The results showed that B4C particles can codeposit in higher percent respect to SiC ones. Ceramic particles increased microhardness of Ni-P coatings to 700HV0.01. The polarization behavior of all the coatings in 3.5% NaCl was similar in as plated state proving that particles did not hindered the passive behaviour. Finally, the effect of heat-treatment (at 400 ºC for 1 hour) on the coating’s properties was studied to compare the contribution of particles and heat-treatment on mechanical and corrosion properties of the coatings. Heat-treatment increased the coating’s microhardness and changed the anodic polarization behavior of the coatings respect to the as plated conditions.

Keywords
Ni-P electrodeposition, SiC, B4C, Microhardness, Polarization
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:hj:diva-38729 (URN)
Conference
EUROCORR 2017, Annual Congress of the European Federation of Corrosion | 20th International Corrosion Congress & Process Safety Congress 2017, September 3–7, 2017, Czech Republic
Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-02-05Bibliographically approved
Péter, L., Zanella, C. & Leisner, P. (2017). European training school for young scientists and EAST Forum 2017. Transactions of the Institute of Metal Finishing, 95(5), 237-238
Open this publication in new window or tab >>European training school for young scientists and EAST Forum 2017
2017 (English)In: Transactions of the Institute of Metal Finishing, ISSN 0020-2967, E-ISSN 1745-9192, Vol. 95, no 5, p. 237-238Article in journal (Other academic) Published
Place, publisher, year, edition, pages
Taylor & Francis, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-37111 (URN)10.1080/00202967.2017.1341725 (DOI)000407570600004 ()2-s2.0-85028421094 (Scopus ID)
Note

Training Course And Conference Report

Available from: 2017-09-01 Created: 2017-09-01 Last updated: 2017-09-12Bibliographically approved
Lekka, M., Zanella, C. & Leisner, P. (2017). New European Training Network solving corrosion problems on micro- and nanoscale: mCBEEs. Transactions of the Institute of Metal Finishing, 95(6), 297-298
Open this publication in new window or tab >>New European Training Network solving corrosion problems on micro- and nanoscale: mCBEEs
2017 (English)In: Transactions of the Institute of Metal Finishing, ISSN 0020-2967, E-ISSN 1745-9192, Vol. 95, no 6, p. 297-298Article in journal (Other academic) Published
Abstract [en]

mCBEEs is an acronym for: Advanced integrative solutions to Corrosion problems beyond micro-scale: towards long-term durability of miniaturised Biomedical, Electronic and Energy systems. It is a doctoral student training network funded by the European Commission under the Marie Sklodowska-Curie Action scheme in the same way as the recently reported training network SELECTA that is focusing on smart electrodeposited alloys for environmentally sustainable applications.

Place, publisher, year, edition, pages
Taylor & Francis, 2017
Keywords
Metal finishing, Surfaces, Corrosion problems, Electrodeposited alloys, Energy systems, European Commission, Long term durability, Nano scale, Student training, Training network, Corrosion
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-37565 (URN)10.1080/00202967.2017.1375186 (DOI)000411067400002 ()2-s2.0-85029617259 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Available from: 2017-10-05 Created: 2017-10-05 Last updated: 2017-10-06Bibliographically approved
Eslami, M., Fedel, M., Speranza, G., Deflorian, F., Andersson, N.-E. & Zanella, C. (2017). Study of selective deposition mechanism of cerium-based conversion coating on Rheo-HPDC aluminium-silicon alloys. Electrochimica Acta, 255, 449-462
Open this publication in new window or tab >>Study of selective deposition mechanism of cerium-based conversion coating on Rheo-HPDC aluminium-silicon alloys
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2017 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 255, p. 449-462Article in journal (Refereed) Published
Abstract [en]

Cerium-based conversion coatings were deposited on Rheo-High Pressure Die Cast (HPDC) Al-Si alloys by immersion in cerium nitrate aqueous solutions. Rheocast Al-Si alloys have a heterogeneous microstructure and present a challenge for the conversion treatment. Different parameters were studied to optimize the conversion coating, and NaCl or H2O2 were also added to the solution to modify or accelerate the deposition process. The mechanism of the coating formation was studied by means of focused ion beam milling (FIB) assisted SEM. The results show that applying cerium-based conversion coating to Al-Si alloys, is possible and a preferential deposition is obtained due to the presence of iron-rich intermetallic particles inside the eutectic region. The formation mechanism of selectively deposited cerium-based conversion coating includes dissolution of aluminium matrix, selective dissolution of aluminium from the noble intermetallic particles, oxidation of iron from the intermetallic particles, and the deposition of cerium hydroxide/oxide layer. The results reveal that the improvement in corrosion resistance in the presence of selectively deposited cerium-based conversion coating is more significant compared to the homogenous coating deposited from the conversion solution containing H2O2. 

Place, publisher, year, edition, pages
Pergamon Press, 2017
Keywords
ELECTROCHEMICAL MICRO-CELL; DIE-CASTING PROCESS; 2024-T3 AL-ALLOY; CORROSION PROTECTION; PITTING CORROSION; A3XX.X/SICP COMPOSITES; SUBSURFACE CREVICES; NACL SOLUTION; SI ALLOYS; 7075-T6
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-38203 (URN)10.1016/j.electacta.2017.09.182 (DOI)000413445000048 ()2-s2.0-85030858525 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Available from: 2017-12-15 Created: 2017-12-15 Last updated: 2018-02-08Bibliographically approved
Zanella, C. & Leisner, P. (2016). A critical review on the use of pulse and pulse reverse plating and their influence on electrodeposition of nanocomposite coatings. In: : . Paper presented at 7th European Pulse Plating Seminar, Vienna, March 3-4, 2016..
Open this publication in new window or tab >>A critical review on the use of pulse and pulse reverse plating and their influence on electrodeposition of nanocomposite coatings
2016 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

Application of pulse and reverse plating to the electrodeposition of composite coatings have been adopted in the last decades but the studies were lacking in consistency of experimental approach. No major conclusion were draw on the effect of using pulse or reverse pulse plating on the codeposition of nanoparticles. Pulse plating is characterized by an increased number of variables and therefore is often difficult to understand the relationship between the parameters and the final results and compare or correlate them to available literature data. In this paper a review of major contributions in this field is carried out trying to compare results and to discuss the effect of pulse parameters on the codeposition of nanoparticles focusing on copper and nickel matrixes.

National Category
Engineering and Technology Materials Engineering
Identifiers
urn:nbn:se:hj:diva-28935 (URN)
Conference
7th European Pulse Plating Seminar, Vienna, March 3-4, 2016.
Note

Invited lecture

Available from: 2016-01-09 Created: 2016-01-09 Last updated: 2016-08-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2924-137X

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