Tribology and Materials | Volume 4 | Issue 1 | 2025 | 38-55
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https://doi.org/10.46793/tribomat.2025.005
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Trends in corrosion resistance of electroless Ni-B-Mo coatings
Manik Barman
1,2,
Tapan Kumar Barman1,
Prasanta Sahoo
1,
1 Jadavpur University, Kolkata, India
2 Heritage Institute of Technology, Kolkata, India
Abstract: Ternary Ni-B-Mo coatings are prepared using various
coating compositions through the chemical deposition method. AISI 1040
steel specimens are used as the substrate to develop coated layers. The
chemical solution compositions are varied to understand their impact on
coating behaviours. A three-electrode-based potentiostat is applied to
determine corrosion behaviour. The experiments are carried out in a 3.5
wt. % NaCl solution. All the coated surfaces displayed a surface
morphology resembling cauliflower. The coated layer thickness increased
from 13 to 42 µm. The boron content increased with NaBH4 concentration,
resulting in an enhancement in corrosion behaviour. The electroless Ni-B
coatings usually become rough, leading to corrosion resistance
deterioration. While the molybdenum concentration does not significantly
impact boron content, it deteriorates the corrosion resistance at its
higher concentrations due to rougher surface morphology. The performance
against corrosion at level 1 is worst due to cracked surface morphology,
while the same performance is best at level 3 concentrations.
Keywords:
electroless, bath composition, Ni-B-Mo, corrosion behaviour, EIS, PDP.
Received: 21-10-2024, Revised: 20-01-2025, Accepted: 20-03-2025
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt,
and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.
2 Heritage Institute of Technology, Kolkata, India
Abstract: Ternary Ni-B-Mo coatings are prepared using various coating compositions through the chemical deposition method. AISI 1040 steel specimens are used as the substrate to develop coated layers. The chemical solution compositions are varied to understand their impact on coating behaviours. A three-electrode-based potentiostat is applied to determine corrosion behaviour. The experiments are carried out in a 3.5 wt. % NaCl solution. All the coated surfaces displayed a surface morphology resembling cauliflower. The coated layer thickness increased from 13 to 42 µm. The boron content increased with NaBH4 concentration, resulting in an enhancement in corrosion behaviour. The electroless Ni-B coatings usually become rough, leading to corrosion resistance deterioration. While the molybdenum concentration does not significantly impact boron content, it deteriorates the corrosion resistance at its higher concentrations due to rougher surface morphology. The performance against corrosion at level 1 is worst due to cracked surface morphology, while the same performance is best at level 3 concentrations.
Keywords: electroless, bath composition, Ni-B-Mo, corrosion behaviour, EIS, PDP.
Received: 21-10-2024, Revised: 20-01-2025, Accepted: 20-03-2025
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt, and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.