Cathodic Disbondment Testing

Cathodic Disbondment Testing is one of test method to evaluate the long-term performance of coating which protecting metal pipe going into underground pipelines.

Corrosion reaction which happened on metal surface under coating layer will cause the cathodic delamination which effect to destruction of adhesion between a coating and the coated surface.

Cathodic Disbondment Test (less disbondment) means that have better corrosion resistance and longevity.

Many standards which develop as test method for Cathodic Disbondment Testing with some different variable. Standard for CDT are ASTM G8, ASTM G42, ASTM G95, CSA Z245.20, ISO 15711, AS3862, NF A 49-711. Different standard have some different variable detailed as below:

Standard	Voltage [V]	Temperature [oC]	Solution [aqueous]	Duration [days]
ASTM G8	1.5	RT	Triple solution	Selection
ASTM G42	1.5	Selection	Triple solution	30
ASTM G80	1.5	RT	Triple solution	60
ASTM G95	1.5	RT	3% NaCl	90
CSA Z2.45.20	1.5 or 3.5	Selection	3% NaCl	Selection
ISO 15711	1.05	RT	Sea water	182
AS 3862	3 mA	Selection	3% NaCl	Selection
NF A 49-711	1.5	Selection	3% NaCl	Selection

Notes:  1. Triple solution is 1/1/1 % solution of NaCl, Na₂SO₄, Na₂CO₃

             2. Selection means multiple choices

             3. Artificial sea water used