Industrial solution for corrosion

1. www.cranfield.ac.uk
20/01/2023

2. Issue
Current Solution
• Corrosion of the conduits is caused by poor
water drainage resulting from the use of
bubble wrap or T harness bag protection with
the velcro facing upward, preventing water
from flowing away and creating a humid
environment.
Storage in open atmosphere
+
Bubble wrap OR T harness bag
Target
Ensuring that water can not reach the
conduits would stop any NC’s being
caused from corrosion.

3. Solution 1
Desiccant - Silica gel
• Physical Property
The chemical formula is xSiO2 · yH2O. Transparent or milky white granular solid. It has an open
porous structure, strong adsorption, and can adsorb a variety of substances.
• Operating Principle
The inside of silicone is a nanoscopic porous structure. Its surface has a large number of hydroxyl
groups, which interact with water molecules in the air through intermolecular attraction.
The moisture absorption of some silica gel is about 40%, even 300%. 200 grams of silica gel
desiccant can absorb at least 80 grams of water.
• Regeneration
Once saturated with water, the gel may be regenerated by heating it to 120 °C (248 °F) for 1–2
hours.

4. Solution 1
Complete desiccant solutions
1. Place 4 silicone gel desiccants (4*50g) in a Moisture
Barrier bag
(The moisture-proof sealing bag should be large enough
to cover the connector and a portion of the cable body.)
2. Wrap the cable connection with the bag
3. Seal the bag with moisture-proof tape
Moisture-Proof Tape
less than £5 per 100m
The cost of the materials consumed for each use is approximately £5.
Silica Gel desiccant
(50g)
£0.2 per
Moisture Barrier Bags
£0.5 per
Program steps

5. Objective of this solution:
Prevent corrosion from appearing on the
connectors
Solution 2
Volatile Corrosion Inhibitors Bag / Paper
Requirements:
1. Prevent water from touching the
aluminium
2. Avoid humidity
Reference: https://www.technologypackaging.com/blog
VCI bag
VCI paper

6. Solution 2
What is it?
● Polyethylene bags act as an emitter
○ Release a non-hazardous vapour into the bag
● Lifespan: Reusable, approximately 2 years
How to put it in place?
● Wrap the bag around the connector
● Seal it with tape on both ends
● Vapour will be released within a few hours
● Dedicated space to store the bags to keep
them safe and reuse them as much as
possible
Reference: https://www.corrosionvci.com/pdf/Emitters_Q_%26_A.pdf

7. Solution 2
shrink-wrapping with zerust® ict®510-ops outdoor preservation vci shrink film
• Water Vapor Transmission Rate 100°F (38°C), 100% RH: 0.108 g/(100 in2/day) 1.64
g/(m2/day)
• Check for sharp corners and edges. Pad edges with ZERUST® VCI foam. After shrinking,
patch thin spots or tears caused by edges with shrink tape

8. Solution 2
Benefit:
• High strength and performance
• 3-year outdoor protection
• Proven corrosion and UV protection
• Excellent shrink properties
• Superior handling and drape
• Safe for electronics
Cost:
Buy 30 for ￡387.48 roughly
Reference: https://mrshrinkwrap.com/20-x-100-8-mil-vci-shrink-film-grey-msw201008fg-vci.html
https://www.zerust.com/products/vci-packaging-films/zerust-ict510-ops-outdoor-preservation-vci-shrink-film/

9. Solution 3
Polystyrene (C8H8)n
Polystyrene moulds/chips
Benefits
• Most suitable for packaging
• water resistant / Hydrophobic
• Inexpensive
• Thermal insulator
Methods
• Moulds for the connectors or any corrosive parts
• Filling the bag with polystyrene chips
Cost
• £3 per Kg
Disadvantage
• Flammable

10. Enzymatic activity due to the presence of water and air lead to formation of Sulfate Reducing
Bacteria (SRB), which can cause MIC.
SRB creates hydrogen sulfide gas and presence of H2S gas in wet condition leads to corrosion of
aluminium.
Greasing and oiling that are presently applied may sufficiently support bacteria that initiate MIC.
SRB test can be performed on water samples, grease and oils to determine the presence of
bacteria.
Titanium shows resistance to corrosion due to MIC but is is heavier and costlier than aluminium.

11. Superhydrophobic coating
Solution 4

12. Cause
Identified cause
● Lack of water drainage
● Greenhouse environment
● Intense moisture shifts
Any unidentified cause?
Microbiologically Induced Corrosion (MIC)
MIC potentially can be a reason for corrosion for aluminium. eg: SRB (Sulfate Reducing Bacteria)
The rate of acceleration may be from 10 to 1000 times the conventional corrosion rates.
Micro-organisms present in contaminated air or water generate biofilms around aluminium and
create a micro environment that is different from the surrounding metal(Dissolved oxygen, pH)
This variation can trigger the production of highly active corrosion cells.

13. Solution for MIC
The solution for MIC is providing a superhydrophobic coating or super-hydrophobic modified
surface on aluminium part.
It has water contact angle greater than 150 degrees which aids self cleaning.
Developing a superhydrophobic modified surface can have 3 approaches.
Mechanical - Applying a chromate based coating
Chemical - Etching
Biological - Using biocides
The most preferred method is to provide a chromate based coating.
Chromate based coating can provide highly effective corrosion protection.
Benefits of chromate based coating:
• Improves corrosion resistance
• Preserves electrical conductivity of the surface
• No change in dimension

14. Cost Analysis
Aluminate clear can be used a chromate based coating.
Cost of 1 litre of Aluminate clear is ￡22.
We assume 0.5L is required for 11 connectors which is used for 1 wing.
Requirement of 70 litres of aluminate clear in one year.
Total cost of purchasing = 70*22 = ￡1540

15. More details are needed?
Background:
jianye.xiao.956@cranfield.ac.uk
Solution1:
haokang.zhou.544@cranfield.ac.uk
yifan.feng.316@cranfield.ac.uk
Solution 2:
ryad.boukhlef.927@cranfield.ac.uk
yu-tang.liu.993@cranfield.ac.uk
Thank you!
Solution 3:
gurumallesh.kundakere.mallikarjunappa.113@cranfield.ac.uk
Solution 4:
albin.panattillayon.133@cranfield.ac.uk