Corrosion in Organic Acids

Corrosion in Organic Acids

The corrosiveness of organic acids is not strong. Corrosion test data in formic acid, acetic acid, and propionic acid show that Ni200, Monel400, and nickel-base and iron-nickel-based corrosion-resistant alloys containing Cr, Mo all show excellent results in boiling solutions. Corrosion resistance, in contrast, corrosion resistance of nickel-base and iron-nickel-based corrosion-resistant alloys added in combination with Mo and Cr is the best. Doping organic acids with oxidants will increase the corrosion of non-Cr alloys. Some corrosion test data are summarized in the following table.

Corrosion of corrosion resistant alloys in organic acids

Grade

corrosion average rate/ mm﹒a⁻¹

10% acetic acid

99% acetic acid

40% formic acid

88% formic acid

alloy 200

/

0.11

0.26-0.27

0.31-0.34

alloy 400

/

0.015

0.038-0.068

0.024-0.028

alloy 825

0.015-0.016

/

0.2

0.064-0.08

alloy 600

/

/

0.25

/

G

0.011-0.014

0.03

0.013

0.099-0.12

G-2

/

0.005

/

0.05-0.067

G-3

/

0.015

0.046-0.05

0.14-0.15

alloy 625

0.01-0.019

0.01

0.17-0.19

0.236-0.238

alloy C-4

/

0.0005

0.07-0.076

0.05-0.076

hastelloy C-276

0.011-0.0114

0.0076

0.07-0.074

0.043-0.048

alloy C-22

/

/

/

0.023

alloy B-2

0.011-0.013

0.03

0.008-0.01

0.00025-0.0041

 

Effect of Oxidizing Ions on Corrosion Resistance of Ni200 and Monel400 in Boiling Acetic Acid

Grade

acetic acid concentration %

corrosion average rate/ mm﹒a⁻¹

no air

blowing air

3800×10⁻⁶Cu²⁺①

alloy 200

100

0.036

0.025

0.81

alloy 400

100

0.0025

0.05

2.97

alloy 200

50

0.076

1.6

0.71

alloy 400

50

0.025

2.1

0.9

 

Corrosion of some alloys in propionic acid

Grade

propionic acid concentration %

corrosion average rate/ mm﹒a⁻¹

50ºC

75ºC

Boiling

monel400

50

0.28

0.13

0.076

80

0.4

0.15

0.25

99

0.48

1.19

0.53

B

50

0.38

0.1

0.05

80

0.61

0.3

0.13

99

0.15

0.64

0.28

C

50

0.025

80

0.025

99

0.025


Post time: Apr-16-2018
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