Download - Chirkov - literature review of Nb electroplating

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Literature Review of Nb Electroplating

Dmytro ChirkovLNL-INFN

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Overview

• Motivation • The process of electroplating• Electrolytes

Aqueous electrolytes Non-aqueous electrolytes

Electrolytes with organic solvents High-temperature melts Ionic liquids

• Conclusions

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Motivation

The main aim of this work is try to understand if

expensive techniques for Nb coating could be

replaced by cheaper electroplating method

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The process of electroplating

CathodeMn+ + ne- → M2H+ + 2e- → H2

AnodeM → Mn+ + ne- 2H2O → O2 + 4H+ + 4e-

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Electrolytes

All electrolytes could be divided into two groups

• Aqueous electrolytes

• Non-aqueous electrolytes Electrolytes with organic solvents High-temperature melts Ionic liquids

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Aqueous electrolytes

Diagram E – pH for system Nb –H2O

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№ Reaction E0, V

1 2H++2e-H2 0

2 Nb5++5e-Nb -0,96

3 Nb3++3e-Nb -1,1

Reactions which can occur on cathode in niobium salts aqueous solutions and their potentials

Niobium can’t be isolated by electrolysis of aqueous solutions of its compounds, since the water would be electrolyzed preferentially

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Parameters of electrolyze

Current density 10-20 A/dm2

Temperature 40-60 °C

Current efficiency 0,1%

Electrolyte

HNbO3 15-17 g/l

HF 120-140 g/l

NH4F 15-20 g/l

Formaldehyde 7-15 g/l

Ajogin F.F. Galvanotechnic. Handbook. 1987

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Parameters

Current density, A/dm2 5-20

Temperature , °C 50-70

Nb content, % 6

Electrolyte g/l

Nb 10-20

Ni2CO3 10-20

HBF6 50-150

EDTA 30-40

OK-3 100-150

PV-20 10-30

NH4OH For pH 2,5-3

Aqueous electrolytesKadaner L.I., Fedchenko V.M.

About electrodeposition of Ni-Nb and Fe-Nb alloys. 1987

Ni-Nb alloy

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Parameters

Current density, A/dm2 5-15

Temperature , °C 15-25

Nb content, % 10

Electrolyte g/l

Nb 10-20

FeCl2 10-20

HBF6 100-200

OK-3 100-150

PV-20 10-30

NH4OH For pH 1,5-2

Aqueous electrolytesKadaner L.I., Fedchenko V.M.

About electrodeposition of Ni-Nb and Fe-Nb alloys. 1987

Fe-Nb alloy

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Non-aqueous electrolytes

Electrolytes with organic solvents

High-temperature melts

Ionic liquids

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Electrolytes with organic solvents

Electrolyte

NbCl5 10-15 g/l

Methanol 300-500 ml/l

Propyl acetate 20-30 ml/l

Benzol 500-600 ml/l


Current density 0,5-1,5 A/dm2


Time 10 min

Thickness 1 μm

The extreme high vapor pressure, flammability and explosiveness makes these solutions dangerous

Kuznetsov V. V., Grigoriev V. P., Osipov O. A. Method of electrochemical deposition of niobium. 1973

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Electrolyte

NbCl5 40-100 g/l

NiCl3 0,1 – 0,3 g/l

Ethanol 96-100%


Current density 20 A/dm2


Current efficiency 0,5 – 1%

Thickness 1 μm

Compact bright Ni-Nb coatings with Nb content ≤1%

Electrolytes with organic solventsFialkov U. Y., Grishchenko V. F.

Electrodeposition of metals from non-aqueous solutions. 1985

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Electrolyte

K2NbF7 17,5%

KCl 55%

KF 27,5%


Current density CathodicAnodic

60-80 A/dm2

15-23 A/dm2


Electrolyzer - hermetically sealedHave been obtained pure Nb with impurities of

C - 0,02wt%; O < 0,05wt%; N - 0,02wt%

High-temperature meltsYagodin G.A., Technology of rare metals in atomic technique.

Moscow, Atomizdat. 1974

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Electrolyte

(Li-Na-K)F-eutectic2,5 wt% K2NbF7


Current density 0,5-3,5 A/dm2


Outgassing the mixture under vacuum at 400 ⁰C for one week to remove adsorbed moisture.

Have been obtained dense coherent deposits of Nb

High-temperature meltsOn the electrodeposition and characterization of niobium from fused

fluoride electrolytes G. P. Capsimalis, E. S. Chen. Journal of Applied Electrochemistry V17, #2 / March, 1987

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Ionic liquidsIonic liquids are molten salts with melting points

below 100 °C

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Ionic liquids

Electrolyte

AlCl3 : EMIC melt(EMIC - 1-ethyl-3-methylimidazolium chloride)

Niobium contents of 10 - 12 % in the co-deposited niobium-aluminum coatings

Niobium Electrodeposition from Low-Valent Niobium Species Graham T. Cheek

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Electrolyte

AlCl3 52 mol%

NaCl 48 mol%


Temperature 190 °C

It was confirmed that aluminium alloys containing Nb could be electrodeposited. However, niobium could

not be deposited in the pure form.Niobium content in alloy – from 3 % to 13%

Ionic liquidsElectrochemical Behaviour of Dissolved Nb, Mo and Ta Species in

Molten Chloroaluminates. Geir Martin Haarberg and Gery Stafford

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Electrolyte[BMP]-Tf2N : 0,25M NbF5 : 0,25M LiF

(BMP - 1-butyl-1-methyl-pyrrolidinium) (Tf2N - bis(tri-fluoromethylsulfonylimide)


Current density 0,5-1 A/dm2

Temperature 100 °C

Layer of niobium deposited on Ni is not very uniform

Ionic liquidsElectrodeposition of Ta and Nb using ionic liquid. Guiseppina Barbato.

A thesis for the degree of Master of Applied Science

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Current density 100 A/dm2

Pulse period 10 ms

Duty ratio 0,2

Temperature 160 °C

Ionic liquids

Electrolyte

NbCl5 19.2 mol%

SnCl2 10 mol%

EMIC 70,8 mol%

Have been obtained Nb-Sn alloy with Nb content – 69,1wt％　

Electrodeposition of Nb3Sn alloy film from Lewis basic NbCl5-SnCl2-EMIC melt Koura N. Electrochemistry V77, I9, September 2009, P798-800

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Conclusions• The electrodeposition of Nb is not possible from aqueous solutions

because the electrochemical potential for this metal falls outside the window of stability for water

• Non-aqueous solutions could be used for Nb electroplating

• With high-temperature melts could be obtained Nb coatings

• Ionic liquids are a relatively new class of materials with properties (wide potentional window, inflammability, low vapour pressure) that makes them attractive for electroplating of Nb

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Thanks for your attention!!!!

Download - Chirkov - literature review of Nb electroplating

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