Coating process: Test Method for cathodic disbonding resistance of antirust paint

Core tip: cathodic stripping of antirust coating: due to the effect of cathodic products, the adhesion between the antirust coating and the substrate is damaged 1 Sample preparation of antirust coating (1) Unless otherwise specified, the base material of the sample product shall be hot-rolled plain carbon steel, with the dimension of 250mm × 150mm × 2mm, The edge shall be deburred and filleted, and a diameter of 5mm shall be drilled at the place 6mm away from the edge on the center line of either side of the two short sides (2) Use M5, 10 mm long copper screw, copper nut Paint knowledge how about Akzo Nobel Powder Coating Recommended introduction: powder coating is a kind of coating with different form from general coating, which is in powder form It is a new type of coating, because of its own advantages and more and more known by people Let's introduce Akzo Nobel Powder coating Akzo Nobel Powder coating is a cost-effective coating solution, which can be applied to different kinds of products After the treatment of static electricity and fire baking, a tough and durable coating surface will be formed, with the least impact on the environment Since the introduction of this technology, powder coating has been able to continue to maintain the Coating home news: antirust coating cathode stripping: due to the role of cathode products, the adhesion between the antirust coating and the substrate is damaged 1 Preparation of antirust coating sample (1) unless otherwise specified, the base material of sample product shall be hot-rolled common carbon steel, with the dimension of 250mm × 150mm × 2mm, and its edge shall be deburred and filleted Drill a 5mm diameter (2) at the place 6 mm away from the edge on the center line of either side of the two short sides Use M5, 10 mm long copper screw, copper nut and copper washer to make a length of 600 Mm, 1 mm diameter copper conductor with plastic insulation is fixed on the connecting hole of the sample base plate After connection, measure the conductivity of the multimeter side wire and the bottom plate connection, and the resistance value shall be less than 0.010 After checking the connection between the conductor and the base plate, the connection point shall be coated with epoxy adhesive or other equivalent adhesive, and the insulation and sealing treatment shall be carried out (3) The coating and dry operation of samples shall be carried out according to the technical requirements of coating products (4) The coating thickness of sample coating products shall be measured and recorded in accordance with the provisions of GB / T 13452.2, and the integrity of the coating shall be checked at low voltage (67.5v) with a wet sponge type pinhole detector If there are pinholes and other defects in the coating, the coating shall be repaired (5) Before starting the test, at the center of each sample, a man-made leakage hole shall be made for the coating, which is a round hole with a diameter of 6 mm coating removed The holes shall be machined with a flat head drill of 6mm diameter and shall not penetrate the metal base plate All coatings in the holes shall be removed to expose bright metal (6) For each single or multi-layer protective coating, prepare a sufficient number of samples, at least three At the same time, prepare three control samples of the same coating, which are not connected with the cathodic protection system in the test 2 Test conditions (1) the test medium is filtered natural seawater or artificial seawater (2) The test temperature is 23 ± 2 ℃ If it is not possible to adjust the sea water temperature to 23 ± 2 ℃, it can be determined according to the environmental conditions, but the temperature of electrolyte in the container shall be measured and recorded regularly 3 Test procedure (1) check, record and take photos of the sample before the test (2) Inject natural seawater or artificial seawater into the plastic tank, adjust the water temperature to the test temperature, and add tap water daily to maintain the original liquid level in the container (3) The magnesium anode is suspended in the center of the container The sample is arranged equidistant from the anode around the container The sample has a man-made leakage hole facing the anode The distance between each sample and anode shall not be less than 150 mm, and the distance between each sample and the bottom of the container shall not be less than 50 mm It is necessary to ensure that the sample is completely immersed and that there is no contact between the samples and the container wall (4) If the space in the container allows, the control sample can be placed in a proper position, but the control sample shall not be connected with the anode If the space in the container is limited, the control sample can be placed in another container, and its test medium and environmental conditions are consistent with the test container, which shall be described in the test report (5) Place the reference electrode near the sample, but do not cover the artificial leakage hole (6) A bolt connector is used to connect the conductor of each sample with the anode conductor The potential between the sample and the reference electrode is stable (7) The test period was 30 days In the first week of the test, the test potential and the coating of the sample shall be checked once a day, twice a week since the second week, and detailed records shall be made after each check During the inspection, take out the sample, wash it carefully with tap water, dry it gently with filter paper or soft cloth, check the blistering, peeling and other damages of the coating, and then put it into the plastic tank again If the coating surface changes significantly, additional photos shall be taken (8) After the test, wash each sample thoroughly with tap water, and handle it carefully without damaging the coating 4 The evaluation of test results (1) firstly, the sample is visually inspected Record the bubble density, size and distance from the artificial holiday coating hole, and evaluate it according to the requirements of GB 9277.2 If the back of the sample is also coated with the same coating, the same inspection shall be carried out (2) Check the reduction of coating adhesion around the artificial holiday coating hole (i.e cathodic stripping): use a sharp knife to gently peel off all loose coatings or peeled coatings along the bottom of the coating at the edge of the artificial holiday coating hole, calculate the stripping area of the effective area of the sample, and take photos of each sample after inspection (3) The same is done for the control sample Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,