research for corrosion and protection

1. (Corrosion Prevention of Steels by Zinc Coatings)
Chloride Ion
Cold Galvanized, ZRP
Cold Galvanized, ZRC
Zinc Metalized
Hot Dip Galvanized
Electroplating
ASTM-B117 JIS-Z2371
ASTM-
B117 Electroplating
Cold Galvanized
JIS-Z2371
ASTM-B117
Corrosion
Electrochemistry
3
1.Electrodes
- Anode
Oxidation ( e-
)
Electrolyte
- Cathode Corrosion
Reduction ( e-
)
Anode Cathode
2.Electrolyte
Electron Anode
Cathode
3.Driving Force Electric Potential
Electron Anode
Cathode
,
Fig.1 Cell Potential and the EMF Series
Corrosion
Corrosion
Corrosion

2. 1. Uniform Attack
Electrolyte
2. Galvanic or Two - Metal Corrosion
Corrosion
Electrolyte
Cathode
Anode
3. Crevice Corrosion ( or Concentration Cell
Corrosion or Gasket Corrosion or Deposit
Corrosion )
4. Pitting Corrosion
Corrosion
Anode Area
5. Intergranular Corrosion
Impurity Grain
Boundaries Alloying Element
Grain Grain Boundaries
Grain Anode Grain
Cathode

3. 6. Stress corrosion
Stress
Corrosive Medium
Mechanic Stress Corrosion
7. Erosion Corrosion
Corrosive Fluid
Corrosive
Erosion
8. Hydrogen Damage
9. Blistering
Blister
Cathode
Blister
Corrosive Condition
Corrosive
(Inhibitor)
Cathode
Cold Galvanized
Zinc Metalized
Hot Dip Galvanized
Electroplating
Electroplating

4. 2
ASTM-B117
JIS-Z2371
1. ASTM-B117
1. 15 x 7 cm2
acetone
acetone
2.
3. Salt Spray Chamber
15o
4. 1
5.
Weight loss
6. 5-6
7. Corrosion rate
2. JIS-Z2371
1. 15 x 8 cm2
2.
3. Salt Spray Chamber
15o
4. 3 1
acetone
5.
6. 4-5 2
(Baht/m2
)
Cold Galvanized (ZRP) 80-90
Cold Galvanized (ZRC) 160-170
Zinc Metallize 50-60
Hot Dip Galvanized 140-160
Electroplating 80-90
-3
Cold Galvanized (ZRP)
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Cumulative Time(hr)
CorrosionRate(mpy)
-4
Cold Galvanized (ZRC)
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Cumulative Time (hr)
CorrosionRate(mpy)

5. -5
Zinc Metallize
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Cumulative Time (hr)
CorrosionRate(mpy)
-6
Hot Dip Galvanized
-7
Electroplating
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Cumulative Time (hr)
CorrosionRate(mpy) ASTM B117
5
Corrosion
Rate (mpy)
Cold Galvanized (ZRP) 1-2
Cold Galvanized (ZRC) 1-2
Hot Dip Galvanized 0.5-1
Zinc Metalized 0.5-1
Electroplating 0-0.5
Cold Galvanized
Cold
Galvanized ZRP ZRC
95%
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Cumulative Time (hr)
CorrosionRate(mpy)

6. Cold Galvanized
ZRP
ZRC
ZRC ZRP
Zinc Metalized
Zinc Metalized
Cold
Galvanized
Hot Dip Galvanized
Hot Dip Galvanized
Galvanize
Cold Galvanized
Zinc Metalized
Hot Dip
Galvanized
Electroplating
Electroplating
Cathode
Anode
5-10 mpy
Blank Test
Cold
Galvanized
JIS-Z2371
5 JIS-
Z2371
63
1. Electroplating
Hot Dip Galvanized, Zinc
Metalized Cold Galvanized
2. Cold Galvanized
(ZRP) (ZRC)
3. 5
4.

7. 1.
2.
Weight Loss
3.
4.
Weight
Loss
5.
Weight Loss
(Corrosion)
Salt Spray Tester
Salt Spray Tester
1. Standard Test Method of Salt Spray (Fog)
Testing ASTM B117-90
2. Standard Practice for Modified Salt Spray
(Fog) Testing ASTM G85- 94
3. Standard Test Method for Evaluation Degree
of Blistering of Paints ASTM D714-87
4. Japanese Indrustrail Standard Method of Salt
Spray Testing JIS Z 2371
5.
6. Mars G. Fontana, “Corrosion Engineering”,
Third Edition, McGraw-Hill Book Company,
P.59-63, 1987.
7. Ichiro Suzuki, “Corrosion Resistant Coating
Technology”, Marcel Dekker INC., New
York, 2989.
8. Frank N. Speller, D.Sc., “Corrosion Causes
and Prevention”, Third Edition, McGraw-
Hill Book Company, Inc., New York and
London, P.344-348, 1951.
9. Denny A. Jones, “Principle and Prevention
of Corrosion”, Second Edition, Prentice Hall,
Inc., P.5,10,499-503, 1996.
10. Joseph F. Eosich, “Corrosion Prevention for
Practicing Engineers, Barnes&Noble Inc.,
New York, P.107-113, 1970.