TY  - JOUR
AU  - D. Jović, Vladimir
PY  - 2022
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1569
AB  - Considering literature of electrochemical impedance spectroscopy (EIS) it was discovered that for calculation of the value of double layer capacitance (Cdl) from the constant phase element (CPE) two equations, with or without solution resistance (Rs) could be used. After calculation of Cdl for defined values of CPE constant Ydl, CPE exponent , Rs and charge transfer resistance (Rct), it was confirmed in this work that different results for Cdl were obtained by including Rs in the calculation of Cdl. It was also stated that “it is quite difficult to understand how both parameters (Rct and Rs) could be expressed by the same time constant, i.e. the same parameter .” By investigating the hydrogen evolution reaction (HER) at Ni mesh 40 electrode in the solution of 1 M KOH at 25 oC using EIS measurements, it was shown that different Cdl vs. E plots were obtained using these two equations for Cdl calculation. A simple solution to avoid this problem with detailed explanation, the use of equation without Rs, has been suggested in this work.
AB  - Razmatrajući literature o elektrohemijskoj impedansnoj spektroskopiji (EIS) ustanovljeno je da za izračunavanje vrednosti kapaciteta dvojnog sloja (Cdl) iz konstantnog faznog elementa (CPE) postoje dve jednačine, jedna u kojoj figuriše otpor elektrolita (Rs) i druga u kojoj ovaj parametar ne figuriše. Izračunavanjem vrednosti Cdl za definisane parametre (Ydl, , Rs, Rct), u ovom radu je pokazano da se dobijaju drugačiji rezultati za Cdl primenom ovih jednačina. Takođe je konstatovano da je neprihvatljivo da oba parametra (Rct i Rs) na isti način zavise od vremenske konstante, odn. od parametra . Ispitivanjem reakcije izdvajanja vodonika na Ni mrežici u rastvoru 1 M KOH na 25 oC korišćenjem impedansnih merenja, pokazano je da su zavisnosti Cdl vs. E, dobijene korišćenjem pomenutih jednačina, različite. Da bi se izbegao ovaj problem predloženo je da se koristi jednačina u kojoj ne figuriše otpor elektrolita (Rs), jer uvodjenje Rs nema korektan fizički smisao.
PB  - Engineering Society for Corrosion, Belgrade, Serbia
T2  - Journal of Materials Protection
T1  - Calculation of a pure double layer capacitance from a constant phase element in the impedance measurements
T1  - Izračunavanje prave vrednosti kapaciteta dvojnog sloja iz konstantnog faznog elementa u impedansnim merenjima
EP  - 57
IS  - 1
SP  - 50
VL  - 63
DO  - 10.5937/zasmat2201050J
ER  - 

@article{
author = "D. Jović, Vladimir",
year = "2022",
abstract = "Considering literature of electrochemical impedance spectroscopy (EIS) it was discovered that for calculation of the value of double layer capacitance (Cdl) from the constant phase element (CPE) two equations, with or without solution resistance (Rs) could be used. After calculation of Cdl for defined values of CPE constant Ydl, CPE exponent , Rs and charge transfer resistance (Rct), it was confirmed in this work that different results for Cdl were obtained by including Rs in the calculation of Cdl. It was also stated that “it is quite difficult to understand how both parameters (Rct and Rs) could be expressed by the same time constant, i.e. the same parameter .” By investigating the hydrogen evolution reaction (HER) at Ni mesh 40 electrode in the solution of 1 M KOH at 25 oC using EIS measurements, it was shown that different Cdl vs. E plots were obtained using these two equations for Cdl calculation. A simple solution to avoid this problem with detailed explanation, the use of equation without Rs, has been suggested in this work., Razmatrajući literature o elektrohemijskoj impedansnoj spektroskopiji (EIS) ustanovljeno je da za izračunavanje vrednosti kapaciteta dvojnog sloja (Cdl) iz konstantnog faznog elementa (CPE) postoje dve jednačine, jedna u kojoj figuriše otpor elektrolita (Rs) i druga u kojoj ovaj parametar ne figuriše. Izračunavanjem vrednosti Cdl za definisane parametre (Ydl, , Rs, Rct), u ovom radu je pokazano da se dobijaju drugačiji rezultati za Cdl primenom ovih jednačina. Takođe je konstatovano da je neprihvatljivo da oba parametra (Rct i Rs) na isti način zavise od vremenske konstante, odn. od parametra . Ispitivanjem reakcije izdvajanja vodonika na Ni mrežici u rastvoru 1 M KOH na 25 oC korišćenjem impedansnih merenja, pokazano je da su zavisnosti Cdl vs. E, dobijene korišćenjem pomenutih jednačina, različite. Da bi se izbegao ovaj problem predloženo je da se koristi jednačina u kojoj ne figuriše otpor elektrolita (Rs), jer uvodjenje Rs nema korektan fizički smisao.",
publisher = "Engineering Society for Corrosion, Belgrade, Serbia",
journal = "Journal of Materials Protection",
title = "Calculation of a pure double layer capacitance from a constant phase element in the impedance measurements, Izračunavanje prave vrednosti kapaciteta dvojnog sloja iz konstantnog faznog elementa u impedansnim merenjima",
pages = "57-50",
number = "1",
volume = "63",
doi = "10.5937/zasmat2201050J"
}

D. Jović, V.. (2022). Calculation of a pure double layer capacitance from a constant phase element in the impedance measurements. in Journal of Materials Protection
Engineering Society for Corrosion, Belgrade, Serbia., 63(1), 50-57.
https://doi.org/10.5937/zasmat2201050J

D. Jović V. Calculation of a pure double layer capacitance from a constant phase element in the impedance measurements. in Journal of Materials Protection. 2022;63(1):50-57.
doi:10.5937/zasmat2201050J .

D. Jović, Vladimir, "Calculation of a pure double layer capacitance from a constant phase element in the impedance measurements" in Journal of Materials Protection, 63, no. 1 (2022):50-57,
https://doi.org/10.5937/zasmat2201050J . .

TY  - JOUR
AU  - Lačnjevac, Uroš
AU  - D. Jović, Vladimir
AU  - Jović, Borka M
AU  - Baščarević, Zvezdana
AU  - Maksimović, Vesna M
AU  - Pavlović, Miomir
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2975
AB  - The electrochemical deposition of the Fe-Ni alloy powders from citrate-sulfate containing electrolytes of different Ni/Fe ions concentration ratios at pH 4.5 was examined by the polarization measurements. All polarization curves have a similar shape and are characterized by the presence of two inflection points. The first inflection point reflects the beginning of alloy deposition, while the second one (˜) corresponds to the moment when the cathode reaction becomes determined by the rate of hydrogen bubbles formation. The potentials of Fe-Ni alloys deposition at all investigated Ni/Fe ratios are more positive than those for pure metal powders deposition. As the Ni/Fe ratio decreases, the polarization curves are placed at slightly more positive potentials. The morphology of electrodeposited powder particles was investigated using scanning electron microscopy (SEM). A common characteristic of all Fe-Ni alloy powders is the presence of cone shaped cavities. Powder particles electrodeposited at the ratio Ni/Fe = 9/1 are mainly consisted of nodules of either very flat surface or rough surface, with well defined crystals detected only on a few particles. With the decrease of the Ni/Fe ratio, the presence of well defined crystals on the nodule surface becomes more pronounced. In the powder with the highest amount of Fe (Ni/Fe = 1/3), the whole surface of all particles is covered with crystals of different shapes.
AB  - Elektrohemijsko taloženje prahova Fe-Ni legura ispitivano je snimanjem polarizacionih dijagrama u citratno-sulfatnim rastvorima pri različitom odnosu koncentracija Ni/Fe jona na pH 4,5. Sve polarizacione krive imaju sličan oblik i okarakterisane su prisustvom dve prevojne tačke na dijagramu. Prva prevojna tačka odgovara početku taloženja Fe-Ni legure, dok druga predstavlja momenat kada ukupna elektrohemijska reakcija postaje kontrolisana brzinom formiranja mehurova vodonika. Potencijali taloženja Fe-Ni legura pri svim ispitivanim odnosima Ni/Fe pozitivniji su od potencijala taloženja čistih metala, pri čemu se sa smanjenjem odnosa Ni/Fe polarizacione krive pomeraju ka malo pozitivnijim vrednostima potencijala. Morfologija čestica prahova ispitivana je korišćenjem skenirajuće elektronske mikroskopije (SEM). Zajednička karakteristika svih prahova Fe-Ni legura je prisustvo šupljina konusnog oblika. Čestice praha istaloženog pri odnosu Ni/Fe = 9/1 uglavnom su sastavljene od čvorića, glatke ili neravne površine, kod kojih se na pojedinim mestima mogu uočiti dobro definisani kristali. Sa smanjenjem odnosa Ni/Fe, prisustvo kristala na površini čvorića postaje sve izraženije, dok su kod praha sa najvećim sadržajem Fe (Ni/Fe = 1/3) na celoj površini čestica prisutni kristali različitog oblika.
PB  - Belgrade, Serbia : Engineering Society for Corrosion
T2  - Zaštita materijala
T1  - Morphology of Fe-Ni alloy powders electrodeposited from citrate-sulfate containing solutions
T1  - Morfologija prahova Fe-Ni legura elektrohemijski istaloženih iz citratno-sulfatnih rastvora
EP  - 241
IS  - 4
SP  - 237
VL  - 52
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2975
ER  - 

@article{
author = "Lačnjevac, Uroš and D. Jović, Vladimir and Jović, Borka M and Baščarević, Zvezdana and Maksimović, Vesna M and Pavlović, Miomir",
year = "2011",
abstract = "The electrochemical deposition of the Fe-Ni alloy powders from citrate-sulfate containing electrolytes of different Ni/Fe ions concentration ratios at pH 4.5 was examined by the polarization measurements. All polarization curves have a similar shape and are characterized by the presence of two inflection points. The first inflection point reflects the beginning of alloy deposition, while the second one (˜) corresponds to the moment when the cathode reaction becomes determined by the rate of hydrogen bubbles formation. The potentials of Fe-Ni alloys deposition at all investigated Ni/Fe ratios are more positive than those for pure metal powders deposition. As the Ni/Fe ratio decreases, the polarization curves are placed at slightly more positive potentials. The morphology of electrodeposited powder particles was investigated using scanning electron microscopy (SEM). A common characteristic of all Fe-Ni alloy powders is the presence of cone shaped cavities. Powder particles electrodeposited at the ratio Ni/Fe = 9/1 are mainly consisted of nodules of either very flat surface or rough surface, with well defined crystals detected only on a few particles. With the decrease of the Ni/Fe ratio, the presence of well defined crystals on the nodule surface becomes more pronounced. In the powder with the highest amount of Fe (Ni/Fe = 1/3), the whole surface of all particles is covered with crystals of different shapes., Elektrohemijsko taloženje prahova Fe-Ni legura ispitivano je snimanjem polarizacionih dijagrama u citratno-sulfatnim rastvorima pri različitom odnosu koncentracija Ni/Fe jona na pH 4,5. Sve polarizacione krive imaju sličan oblik i okarakterisane su prisustvom dve prevojne tačke na dijagramu. Prva prevojna tačka odgovara početku taloženja Fe-Ni legure, dok druga predstavlja momenat kada ukupna elektrohemijska reakcija postaje kontrolisana brzinom formiranja mehurova vodonika. Potencijali taloženja Fe-Ni legura pri svim ispitivanim odnosima Ni/Fe pozitivniji su od potencijala taloženja čistih metala, pri čemu se sa smanjenjem odnosa Ni/Fe polarizacione krive pomeraju ka malo pozitivnijim vrednostima potencijala. Morfologija čestica prahova ispitivana je korišćenjem skenirajuće elektronske mikroskopije (SEM). Zajednička karakteristika svih prahova Fe-Ni legura je prisustvo šupljina konusnog oblika. Čestice praha istaloženog pri odnosu Ni/Fe = 9/1 uglavnom su sastavljene od čvorića, glatke ili neravne površine, kod kojih se na pojedinim mestima mogu uočiti dobro definisani kristali. Sa smanjenjem odnosa Ni/Fe, prisustvo kristala na površini čvorića postaje sve izraženije, dok su kod praha sa najvećim sadržajem Fe (Ni/Fe = 1/3) na celoj površini čestica prisutni kristali različitog oblika.",
publisher = "Belgrade, Serbia : Engineering Society for Corrosion",
journal = "Zaštita materijala",
title = "Morphology of Fe-Ni alloy powders electrodeposited from citrate-sulfate containing solutions, Morfologija prahova Fe-Ni legura elektrohemijski istaloženih iz citratno-sulfatnih rastvora",
pages = "241-237",
number = "4",
volume = "52",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2975"
}

Lačnjevac, U., D. Jović, V., Jović, B. M., Baščarević, Z., Maksimović, V. M.,& Pavlović, M.. (2011). Morphology of Fe-Ni alloy powders electrodeposited from citrate-sulfate containing solutions. in Zaštita materijala
Belgrade, Serbia : Engineering Society for Corrosion., 52(4), 237-241.
https://hdl.handle.net/21.15107/rcub_rimsi_2975

Lačnjevac U, D. Jović V, Jović BM, Baščarević Z, Maksimović VM, Pavlović M. Morphology of Fe-Ni alloy powders electrodeposited from citrate-sulfate containing solutions. in Zaštita materijala. 2011;52(4):237-241.
https://hdl.handle.net/21.15107/rcub_rimsi_2975 .

Lačnjevac, Uroš, D. Jović, Vladimir, Jović, Borka M, Baščarević, Zvezdana, Maksimović, Vesna M, Pavlović, Miomir, "Morphology of Fe-Ni alloy powders electrodeposited from citrate-sulfate containing solutions" in Zaštita materijala, 52, no. 4 (2011):237-241,
https://hdl.handle.net/21.15107/rcub_rimsi_2975 .

TY  - JOUR
AU  - Lačnjevac, Uroš
AU  - D. Jović, Vladimir
AU  - Jović, Borka M
AU  - Baščarević, Zvezdana
AU  - Pavlović, Miomir
PY  - 2008
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2921
AB  - The electro deposition of the Ni-Mo-O alloy powders from ammonium sulfate containing electrolytes of different Ni/Mo ions concentration ratios was investigated by the polarization measurements. In all electrolytes similar polarization curves were obtained, characterized by two inflection points Point A, the beginning of the electro deposition process and point B, a moment when the powder electro deposition is controlled by the hydrogen bubbles formation. The morphology of the electrodeposited Ni-Mo-O alloy powders was investigated using SEM. At Ni/Mo ratios higher or equal to 1/1 two types of particles were detected in the powder deposits: spongy-type particles (100 - 200 μm) with flat nodular surface and presence of cavities and agglomerates of similar dimensions characterized by the presence of cracks and cavities, with the nodular surface that is not flat, but is covered by the freshly formed dendrites. At Ni/Mo ratios of 1/3 the contribution of the amorphous-compact deposit is significant, while on top of this deposit rounded dendritic and compact outgroths were detected.
AB  - Elektrohemijsko taloženje prahova Ni-Mo-O legura ispitivano je snimanjem polarizacionih dijagrama u sulfatno-amonijačnim elektrolitima pri različitim odnosima Ni/Mo. Sve polarizacione krive okarakterisane su prisustvom dve prelomne tačke (A i B) na dijagramu. Tačka A odgovara početku taloženja Ni-Mo-O legure, dok tačka B reflektuje momenat kada je ukupna elektrohemijska reakcija kontrolisana brzinom formiranja mehurova gasovitog vodonika pri čemu se sa povećanjem koncentracije MoO4 2- jona u elektrolitu potencijal početka taloženja (tačka A) pomera ka negativnijim vrednostima. Morfologija čestica prahova ispitivana je skenirajućom elektronskom mikroskopijom (SEM). Prahovi istaloženi na staklastom ugljeniku iz elektrolita sa Ni/Mo ≥ 1/1 okarakterisani su prisustvom dve vrste čestica: sunđeraste čestice veličine 100 - 200 μm relativno glatkih površina sa jasno izraženim rupama i aglomerati sličnih veličina na kojima su prisutne jasno izražene naprsline i rupe, čija površina nije glatka i pokriveni su novo stvorenim grozdovima dendritičnog taloga. Za čestice praha istaloženog iz elektrolita koji sadrži odnos jona Ni/Mo = 1/3 karakteristično je da je udeo kompaktnog taloga značajan u poređenju sa ostalim prahovima, na kome se mogu registrovati dva tipa loptastih izraslina: manje kompaktne izrasline sa jasno definisanim dendritima i znatno kompaktnije izrasline. Kod prahova istaloženih na elektrodi od Ni, pored vrsta čestica koje su registrovane pri taloženju prahova na elektrodi od staklastog ugljenika, može se videti da se deo kompaktnog taloga praktično sastoji iz slojevitih struktura koje su posledica favorizovanog epitaksijalnog rasta taloga na srodnim podlogama.
PB  - Belgrade, Serbia : Engineering Society for Corrosion
T2  - Zaštita materijala
T1  - Morphology of Ni-Mo-O alloy powders electrodeposited from ammonium sulfate solutions
T1  - Morfologija prahova Ni-Mo-O legura istaloženih elektrohemijskim postupkom iz rastvora amonijum sulfata
EP  - 46
IS  - 1
SP  - 41
VL  - 49
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2921
ER  - 

@article{
author = "Lačnjevac, Uroš and D. Jović, Vladimir and Jović, Borka M and Baščarević, Zvezdana and Pavlović, Miomir",
year = "2008",
abstract = "The electro deposition of the Ni-Mo-O alloy powders from ammonium sulfate containing electrolytes of different Ni/Mo ions concentration ratios was investigated by the polarization measurements. In all electrolytes similar polarization curves were obtained, characterized by two inflection points Point A, the beginning of the electro deposition process and point B, a moment when the powder electro deposition is controlled by the hydrogen bubbles formation. The morphology of the electrodeposited Ni-Mo-O alloy powders was investigated using SEM. At Ni/Mo ratios higher or equal to 1/1 two types of particles were detected in the powder deposits: spongy-type particles (100 - 200 μm) with flat nodular surface and presence of cavities and agglomerates of similar dimensions characterized by the presence of cracks and cavities, with the nodular surface that is not flat, but is covered by the freshly formed dendrites. At Ni/Mo ratios of 1/3 the contribution of the amorphous-compact deposit is significant, while on top of this deposit rounded dendritic and compact outgroths were detected., Elektrohemijsko taloženje prahova Ni-Mo-O legura ispitivano je snimanjem polarizacionih dijagrama u sulfatno-amonijačnim elektrolitima pri različitim odnosima Ni/Mo. Sve polarizacione krive okarakterisane su prisustvom dve prelomne tačke (A i B) na dijagramu. Tačka A odgovara početku taloženja Ni-Mo-O legure, dok tačka B reflektuje momenat kada je ukupna elektrohemijska reakcija kontrolisana brzinom formiranja mehurova gasovitog vodonika pri čemu se sa povećanjem koncentracije MoO4 2- jona u elektrolitu potencijal početka taloženja (tačka A) pomera ka negativnijim vrednostima. Morfologija čestica prahova ispitivana je skenirajućom elektronskom mikroskopijom (SEM). Prahovi istaloženi na staklastom ugljeniku iz elektrolita sa Ni/Mo ≥ 1/1 okarakterisani su prisustvom dve vrste čestica: sunđeraste čestice veličine 100 - 200 μm relativno glatkih površina sa jasno izraženim rupama i aglomerati sličnih veličina na kojima su prisutne jasno izražene naprsline i rupe, čija površina nije glatka i pokriveni su novo stvorenim grozdovima dendritičnog taloga. Za čestice praha istaloženog iz elektrolita koji sadrži odnos jona Ni/Mo = 1/3 karakteristično je da je udeo kompaktnog taloga značajan u poređenju sa ostalim prahovima, na kome se mogu registrovati dva tipa loptastih izraslina: manje kompaktne izrasline sa jasno definisanim dendritima i znatno kompaktnije izrasline. Kod prahova istaloženih na elektrodi od Ni, pored vrsta čestica koje su registrovane pri taloženju prahova na elektrodi od staklastog ugljenika, može se videti da se deo kompaktnog taloga praktično sastoji iz slojevitih struktura koje su posledica favorizovanog epitaksijalnog rasta taloga na srodnim podlogama.",
publisher = "Belgrade, Serbia : Engineering Society for Corrosion",
journal = "Zaštita materijala",
title = "Morphology of Ni-Mo-O alloy powders electrodeposited from ammonium sulfate solutions, Morfologija prahova Ni-Mo-O legura istaloženih elektrohemijskim postupkom iz rastvora amonijum sulfata",
pages = "46-41",
number = "1",
volume = "49",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2921"
}

Lačnjevac, U., D. Jović, V., Jović, B. M., Baščarević, Z.,& Pavlović, M.. (2008). Morphology of Ni-Mo-O alloy powders electrodeposited from ammonium sulfate solutions. in Zaštita materijala
Belgrade, Serbia : Engineering Society for Corrosion., 49(1), 41-46.
https://hdl.handle.net/21.15107/rcub_rimsi_2921

Lačnjevac U, D. Jović V, Jović BM, Baščarević Z, Pavlović M. Morphology of Ni-Mo-O alloy powders electrodeposited from ammonium sulfate solutions. in Zaštita materijala. 2008;49(1):41-46.
https://hdl.handle.net/21.15107/rcub_rimsi_2921 .

Lačnjevac, Uroš, D. Jović, Vladimir, Jović, Borka M, Baščarević, Zvezdana, Pavlović, Miomir, "Morphology of Ni-Mo-O alloy powders electrodeposited from ammonium sulfate solutions" in Zaštita materijala, 49, no. 1 (2008):41-46,
https://hdl.handle.net/21.15107/rcub_rimsi_2921 .