Degree Level: Bachelor of Science Undergraduate Category ...
Degree Level: Bachelor of Science Undergraduate Category: Engineering and Technology Abstract ID# 1212
Results
Abstract
Experimental
Nickel contact dermatitis is a skin sensitization to nickel and is the most common form of metal contact dermatitis. Once an individual develops nickel dermatitis, they will always be sensitive to the metal when coming in contact with the skin1,2.
Galvanostatic Deposition Conditions Rotating cylinder brass substrate electrode Rotation rate of 500 rpm Room temperature
NiW and NiMo alloys are of interest as they increase corrosion resistance and, specifically, to nickel contact dermatitis, are more environmentally friendly and safe compared to alternatives such as previously explored nickel alloys with chrome3. In this work, NiMoW and NiMo alloys were electrodeposited onto a brass, rotating cylinder substrate at varying current densities and then examined through potentiodynamic polarization in a synthetic sweat solution in a three electrode cell. The corrosion current density, Tafel slope, and corrosion potential were compared for samples as well as the alloy composition characterized by x-ray fluorescence. Polarization curves of varying samples showed beneficial corrosion resistance effects with NiMo alloys and in the tungsten-containing alloys but with lower tungsten levels in the deposit.
Background The corrosion rate, icorr, is found by linear extrapolation of the Tafel regime. When the total current density is zero the potential corresponds to the corrosion potential, Ecorr. We seek to have a low icorr and more positive Ecorr.
NiMoW Electrolyte • • • • •
1.0M boric acid 0.375M sodium citrate 0.075M sodium tungstate 0.005M sodium molybdate 0.15M nickel sulfate
NiMo Electrolyte
Figure 2: Galvanostatic setup
• • • •
Substrate
1.0M boric acid 0.375M sodium citrate 0.080M sodium molybdate 0.15M nickel sulfate
Figure 4: Comparing NiMo and NiMoW Electrodeposits Parameters
Anodic Potentiodynamic Polarization Conditions Rotation rate of 500 rpm T1: room temperature T2: 98.6°F Rotation rate of 500 rpm Between 30 to 450 mA/cm2
Artificial Sweat Solution • • • •
icorr, A/cm2 Tafel Slope, mV/dec ECorr, mV vs Ag/AgCl Current Density (mA/cm2) Temperature
65 NiMoW
CE : Pt mesh
230 NiMo
2.1E-04 6.9E-05 2.7E-04 89 112 201 -0.23 -0.51 -0.55 NA 65 230 Room Temperature Room Temperature Room Temperature
0.05M sodium chloride 0.01M lactic acid 0.02M urea pH adjusted to 6.5 with ammonium hydroxide4
Sample Number
RE : Ag/AgCl
In the kinetic regime the anodic current density is governed by the Tafel equation
Brass
230 NiMo 37C
450 NiMo
5.0E-04 241 -0.54 230 98.6°F
4.8E-05 281 -0.84 450 Room Temperature
Deposit Alloy Thickness Composition
65 NiMoW
1.05 micron
450 NiMo
0.674 micron
Ni: 36.88 Mo: 21.04 W: 42.08 Ni: 30.85 Mo: 69.16
Average of deposit thickness of samples was 0.876 microns
Substrate
WE : Brass
Figure 5: Comparing NiMoW Electrodeposit Measurements to Brass Figure 3: Schematic of Potentiodynamic setup
On a semi-log plot the Tafel slope is identified
RCE alloy deposited samples, a dimensionally stable anode (DSA) of platinum, and a Ag/AgCl reference electrode used. Deposit composition was measured by x-ray fluorescence (XRF) and polarization curves were generated.
References
Figure 1: Tafel slope calculating and location of the corrosion current density and corrosion potential
1. I. Duarte, J.R. Amorim, E.F. Perázzio, R Schmitz, “Dermatite de contato por metais: prevalência de sensibilização ao níquel, cobalto e cromo” An Bras Dermatol. 2005; 80(2):137-42 2. L. T. Menné & D. Burrows, British Journal of Dermatology, 134 (2), 193-198 (1996). 3. N. Tsyntsaru, H. Cesiulis, M. Donten, J. Sorte, E. Pellicer, and E. J. PodlahaMurphy, “Modern Trends in Tungsten Alloys Electrodeposition with Iron Group Metals,” Surface Engineering and Applied Electrochemistry, 48 (6) 491–520 (2012) 4. M.S. Jellesen & P. Møller, Plating and Surface Finishing, 92 (10), 36-41 (2005).
Parameters icorr, A/cm2 Tafel Slope, mV/dec ECorr, mV vs Ag/AgCl Current Density (mA/cm2) Temperature
30 NiMo
100 NiMo
190 NiMo
3.2E-04 3.7E-04 3.0E-04 280 150 249 -0.54 -0.63 -0.62 30 100 190 Room Temperature Room Temperature Room Temperature
190 NiMo 37C 3.5E-04 283 -0.74 190 37
450 NiMo 37C 9.9E-04 262 -0.82 450 37
Conclusions The electrodeposited thin films of NiMo and NiMoW were fabricated and their corrosion resistance was examined in an artificial sweat solution. The lowest corrosion current density was found with a NiMo deposit at high current density -450 mA/cm2; in general, films with no tungsten had a lower corrosion potential, but a more beneficial corrosion current density. Low current density deposited samples (
Results
Abstract
Experimental
Nickel contact dermatitis is a skin sensitization to nickel and is the most common form of metal contact dermatitis. Once an individual develops nickel dermatitis, they will always be sensitive to the metal when coming in contact with the skin1,2.
Galvanostatic Deposition Conditions Rotating cylinder brass substrate electrode Rotation rate of 500 rpm Room temperature
NiW and NiMo alloys are of interest as they increase corrosion resistance and, specifically, to nickel contact dermatitis, are more environmentally friendly and safe compared to alternatives such as previously explored nickel alloys with chrome3. In this work, NiMoW and NiMo alloys were electrodeposited onto a brass, rotating cylinder substrate at varying current densities and then examined through potentiodynamic polarization in a synthetic sweat solution in a three electrode cell. The corrosion current density, Tafel slope, and corrosion potential were compared for samples as well as the alloy composition characterized by x-ray fluorescence. Polarization curves of varying samples showed beneficial corrosion resistance effects with NiMo alloys and in the tungsten-containing alloys but with lower tungsten levels in the deposit.
Background The corrosion rate, icorr, is found by linear extrapolation of the Tafel regime. When the total current density is zero the potential corresponds to the corrosion potential, Ecorr. We seek to have a low icorr and more positive Ecorr.
NiMoW Electrolyte • • • • •
1.0M boric acid 0.375M sodium citrate 0.075M sodium tungstate 0.005M sodium molybdate 0.15M nickel sulfate
NiMo Electrolyte
Figure 2: Galvanostatic setup
• • • •
Substrate
1.0M boric acid 0.375M sodium citrate 0.080M sodium molybdate 0.15M nickel sulfate
Figure 4: Comparing NiMo and NiMoW Electrodeposits Parameters
Anodic Potentiodynamic Polarization Conditions Rotation rate of 500 rpm T1: room temperature T2: 98.6°F Rotation rate of 500 rpm Between 30 to 450 mA/cm2
Artificial Sweat Solution • • • •
icorr, A/cm2 Tafel Slope, mV/dec ECorr, mV vs Ag/AgCl Current Density (mA/cm2) Temperature
65 NiMoW
CE : Pt mesh
230 NiMo
2.1E-04 6.9E-05 2.7E-04 89 112 201 -0.23 -0.51 -0.55 NA 65 230 Room Temperature Room Temperature Room Temperature
0.05M sodium chloride 0.01M lactic acid 0.02M urea pH adjusted to 6.5 with ammonium hydroxide4
Sample Number
RE : Ag/AgCl
In the kinetic regime the anodic current density is governed by the Tafel equation
Brass
230 NiMo 37C
450 NiMo
5.0E-04 241 -0.54 230 98.6°F
4.8E-05 281 -0.84 450 Room Temperature
Deposit Alloy Thickness Composition
65 NiMoW
1.05 micron
450 NiMo
0.674 micron
Ni: 36.88 Mo: 21.04 W: 42.08 Ni: 30.85 Mo: 69.16
Average of deposit thickness of samples was 0.876 microns
Substrate
WE : Brass
Figure 5: Comparing NiMoW Electrodeposit Measurements to Brass Figure 3: Schematic of Potentiodynamic setup
On a semi-log plot the Tafel slope is identified
RCE alloy deposited samples, a dimensionally stable anode (DSA) of platinum, and a Ag/AgCl reference electrode used. Deposit composition was measured by x-ray fluorescence (XRF) and polarization curves were generated.
References
Figure 1: Tafel slope calculating and location of the corrosion current density and corrosion potential
1. I. Duarte, J.R. Amorim, E.F. Perázzio, R Schmitz, “Dermatite de contato por metais: prevalência de sensibilização ao níquel, cobalto e cromo” An Bras Dermatol. 2005; 80(2):137-42 2. L. T. Menné & D. Burrows, British Journal of Dermatology, 134 (2), 193-198 (1996). 3. N. Tsyntsaru, H. Cesiulis, M. Donten, J. Sorte, E. Pellicer, and E. J. PodlahaMurphy, “Modern Trends in Tungsten Alloys Electrodeposition with Iron Group Metals,” Surface Engineering and Applied Electrochemistry, 48 (6) 491–520 (2012) 4. M.S. Jellesen & P. Møller, Plating and Surface Finishing, 92 (10), 36-41 (2005).
Parameters icorr, A/cm2 Tafel Slope, mV/dec ECorr, mV vs Ag/AgCl Current Density (mA/cm2) Temperature
30 NiMo
100 NiMo
190 NiMo
3.2E-04 3.7E-04 3.0E-04 280 150 249 -0.54 -0.63 -0.62 30 100 190 Room Temperature Room Temperature Room Temperature
190 NiMo 37C 3.5E-04 283 -0.74 190 37
450 NiMo 37C 9.9E-04 262 -0.82 450 37
Conclusions The electrodeposited thin films of NiMo and NiMoW were fabricated and their corrosion resistance was examined in an artificial sweat solution. The lowest corrosion current density was found with a NiMo deposit at high current density -450 mA/cm2; in general, films with no tungsten had a lower corrosion potential, but a more beneficial corrosion current density. Low current density deposited samples (
