Cathodic Disbondment
Monday, July 11, 2011
Cathodic Disbonding Tester
Spontaneous holidays may also be caused by such potentials. Test method provides accelerated conditions for cathodic disbondment to occur and provides a measure of resistance of coatings to this type of action. Cathodic disbondment tester is used in civil engineering for evaluation of epoxy coated rebars to evaluate effect of cathodic protection on epoxy-coated rebar.
CD Tester - Cathodic Disbonding tester is one of the useful instrument to test and determine accelerated corrosion testing. Cathodic disbondment tester is manufactured with latest microprocessor based technology with multi channel based on potentiostat operations. The instrument is highly user friendly and can be operated by technicians without any factory training. Cathodic Disbondment instrument has connections made easy with plug and play devices. Full details of installation and operations are given in user manual.
In electrochemical process, A potentiostat is a controlled and measured device in an electrolytic cell, keeps the potential of the working electrode at a constant level with respect to the reference electrode. It consists of an electric circuit which controls the potential across the cell by sensing changes in its resistance, varying accordingly the current supplied to the system: a higher resistance will result in a decreased current, while a lower resistance will result in an increased current, in order to keep the voltage constant.
Few highlights
* User can select potentiostat channel by using soft press key pad to see display of voltage,
current and elapsed test time.
* User has two options to choose model CD-205 and CD-2055
* User has option of adjustable knob for precision control of voltage.
* CD tester with 0-2500mV ±0.2% with current range of 2.5mA or 25mA
* CD Tester with 0-4000mV ± 0.2% with current range of 25mA or 250mA is also available
* Complete instrument is provided is required accessories.
* 2 acrylic glass test cups
* 2 set of reference electrodes
* 1 set connection cable
* Power supply 230 V/50 Hz
Monday, April 25, 2011
Cathodic Disbondment Testing
Cathodic delamination can be defined as the destruction of adhesion between a coating and the coated surface, caused by products of a corrosion reaction.
This basically means the coating delaminates or lifts and separates from the substrate, even though it exhibits good adhesion prior to exposure service conditions.
Experience in the oil and gas industry has clearly shown that coatings with better cathodic disbondment resistance (less disbondment), have better corrosion resistance and greater longevity. Cathodic disbondment is often selected as the key performance test for adhesion, as it simulates field conditions for disbonding of a coating from a pipeline. Some of the test methods can also use applied to coated rebar. Here are a few examples of standards we can test for:
ASTM G8 Involves having the pipe samples immersed in electrolyte at ambient conditions, common anode placed in electrolyte for all samples
ASTM G42 Is the same as G8, except the pipeline coating samples are subjected to elevated temperatures
ASTM G80 Is the same as G8, except that no options for variables are presented
ASTM G95 Is an attached cell method, a plastic cell is attached to the coated panel or pipe, filled with electrolyte, CP applied with individual fretted tube anode.
In Canada, the CSA standards call up these same methods, with the exception that they also provide pass/fail criteria. The electrolyte is a mixture of various salts including NaCl, KCl and sodium bicarbonate, depending on the test method.
Wednesday, March 16, 2011
Cathodic Disbondment
Purpose of coating system is to prevent corrosion that could occur in the underground pipeline services. Importance of coating inspection is therefore highly important. Underground pipes are coated and cathodically protected. Applied cathodic protection potentials may cause loosening of the coating, beginning at holiday edges. Spontaneous holidays may also be caused by such potentials. Test method provides accelerated conditions for cathodic disbondment to occur and provides a measure of resistance of coatings to this type of action. Cathodic disbondment tester is used in civil engineering for evaluation of epoxy coated rebars to evaluate effect of cathodic protection on epoxy-coated rebar.
CD Tester - Cathodic Disbonding tester is one of the useful instrument to test and determine accelerated corrosion testing. Cathodic disbondment tester is manufactured with latest microprocessor based technology with multi channel based on potentiostat operations. The instrument is highly user friendly and can be operated by technicians without any factory training. Cathodic Disbondment instrument has connections made easy with plug and play devices. Full details of installation and operations are given in user manual.
In electrochemical process, A potentiostat is a controlled and measured device in an electrolytic cell, keeps the potential of the working electrode at a constant level with respect to the reference electrode. It consists of an electric circuit which controls the potential across the cell by sensing changes in its resistance, varying accordingly the current supplied to the system: a higher resistance will result in a decreased current, while a lower resistance will result in an increased current, in order to keep the voltage constant.
CD Tester meets or exceeds the requirement of ASTM G8- Test methods for cathodic disbonding of pipeline coatings, ASTM G42- Standard test method for cathodic disbonding of pipeline coatings subjected to elevated temperatures, ASTM G95- Test method for cathodic disbondment test of pipeline coatings using cell method, DIN 30671 and EN 12068 standard, ISO 15711- Determination of resistance to cathodic disbonding of coatings exposed to sea water.