Natural Science
Ataliba Miguel
Corrosiveness of Different
Types of Water
Te c h n i c a l R e p o r t
The Robert Gordon University
Corrosiveness of
various types of
water
Materials & Corrosion Science
Technical Report
Ataliba Miguel ABSTRACT
The corrosiveness of three different types of water was analysed through
an experiment carried out with iron nails immersed in a bath for a period
of 25 days. The types of water used during the experiment were
respectively synthetic seawater, mineral water and sparkling water. The
iron nails immersed in a bath of both synthetic seawater and mineral
water suffered a corrosive attack characterized by the formation of
reddish brown flakes which have adhered the surface of the iron nails.
Whilst, on the other experiment, the iron nail immersed in the sparkling
water suffered a very minimal corrosive attack owing to the formation of
a protective layer which prevented the underlying steel from further
dissolution.
1
1.
Introduction
Objectives/Aims
1.1
Methods
1.2
Experiment Layout
Synthetic seawater – chemical composition
2.1
Mineral water – chemical composition
2.2
CO2 Water – chemical composition
2.3
6
6
6
6
6
7
8
3.
Visual Observations
Synthetic Seawater
3.1
Mineral Water
3.2
Mineral Water (CO2 added)
3.3
9
9
10
11
4.
Discussion
Corrosion of Iron
4.1
4.1.1. Rust
4.1.2. Temperature Effect
4.1.3. pH Effect
CO2 Dissolved in water
4.2
12
12
12
13
13
14
2.
4.2.1. CO2 corrosion mechanism
5.
6.
7.
4.2.2. pH Effect
4.2.3. Temperature Effect
Conclusion
References
Annexes
14
15
16
16
16
18
List of Figures
Figure 1 – Synthetic Seawater
Figure 2 – Mineral water picture
Figure 3 – Sparkling water picture
Figure 4 – Iron nail immersed in synthetic seawater
Figure 5 – Iron nail immersed in mineral water
Figure 6 – Iron nail immersed in sparkling water
Figure 7 – Corrosion of iron in aerated water
6
8
9
10
11
12
13
List of Tables
Table 1 – Synthetic water chemical composition
Table 2 – Mineral water chemical composition
Table 3 – Sparkling water chemical composition
7
7
8
List of graphs
Graph 1 - Effect of pH on the corrosion rate of iron
Graph 2 – Pourbaix diagram of iron
14
21
2