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    Home > Coatings News > Paints and Coatings Market > Coating process: wet sulfur dioxide corrosion resistance test

    Coating process: wet sulfur dioxide corrosion resistance test

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
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    It is suggested that coatings in chemical environment are often corroded by chemical gases such as sulfur dioxide, which leads to premature failure of coatings Therefore, it is of great significance to determine the corrosion resistance of sulfur dioxide to coatings for evaluating the corrosion resistance of organic coatings ISO 3231, paints and varnishes - Determination of resistance to wet sulfur dioxide, has been developed by the international standards organization ISO 3231 specifies the method and equipment for the determination of the resistance of paints, varnishes and related products to moisture and sulfur dioxide This method allows the use of different amounts of sulfur dioxide For thickness ≤ 40 & M Shenyang steel structure fireproof coating construction expert punde Building Fire Engineering Co., Ltd Recommended introduction: since its establishment, Shenyang punde Construction Fire Engineering Co., Ltd has cultivated a group of professional construction teams with excellent equipment, rich experience and serious responsibility with advanced and scientific management methods and strict engineering quality assurance and after-sales service system It has undertaken a number of fire system installation projects, which has been praised by customers Every idea and special requirement of you will be fully considered by us and fully realized in the construction technology, which will become the cornerstone of our successful long-term development We are looking forward to your invitation, to provide you with quality services and high-quality technical support! All construction coatings have passed ISO9001 Coating home news: in the chemical environment, the coating is often corroded by sulfur dioxide and other chemical gases, leading to premature failure of the coating Therefore, it is of great significance to determine the corrosion resistance of sulfur dioxide to coatings for evaluating the corrosion resistance of organic coatings ISO 3231, paints and varnishes - Determination of resistance to wet sulfur dioxide, has been developed by the international standards organization ISO 3231 specifies the method and equipment for the determination of the wet sulfur dioxide resistance of paints, varnishes and related products This method allows the use of different amounts of sulfur dioxide For coatings with thickness ≤ 40 μ m, it is better to use 0.2L sulfur dioxide Before the sulfur dioxide resistance test of the coating, the test parties shall determine the following contents according to national standards, documents or through consultation: 1) material and surface treatment of the base plate; 2) construction process of the coating on the base material; 3) coating system, number of layers and thickness; 4) drying conditions and time of the sample plate before the test; 5 )Test conditions and time, including the amount of sulfur dioxide used (0.2L, 1L or other quantities); 6) inspection methods for evaluating the corrosion resistance of coatings and factors to be considered 1 The coating inspection equipment generally uses a gas tight box with a volume of (300 ± 10) l, a door that can be tightly closed, and equipped with temperature regulating device, heating device, sample support, gas guide pipe and other components See Figure 1 and Figure 2 for a typical sulfur dioxide test box The box is made of inert material, the bottom and the lower part of the box wall are heat-resistant, and can hold at least 2.5L of sulfur dioxide soluble water without leakage The shape of the test chamber may have some changes, but it is necessary to avoid the moisture condensation on the lid dropping on the test plate of the chamber, so that the top of the chamber and the horizontal plane are at an angle of about 12 ° to meet the requirements The temperature regulating device includes a temperature sensor installed on the upper part of the test chamber and a thermometer capable of reading from the outside of the test chamber The mercury ball of the thermometer is 150 mm away from the top and door of the chamber and 250 mm away from the nearest wall of the chamber The heating device shall be able to raise the temperature in the test chamber to (40 ± 3) ℃ within 1.5h and maintain this temperature The gas inlet pipe is located about 50 mm above the bottom of the box The gas enters the test box through the guide pipe There is a pressure reducing valve on or near the top of the test box When the gas in the box is overpressured, it is discharged through this valve In addition, there is a drain tap at the bottom of the chamber Bottled liquid sulfur dioxide is a common gas source It can also react with sodium sulfite and sulfuric acid to generate sulfur dioxide gas outside the tank It is equipped with a proper regulator and measuring instrument (such as flowmeter) to measure the gas volume transported into the test box The sample bracket can be made of coating or inert materials The support shall be of sufficient size to accommodate a test panel with a total surface area of 0.5m2 Fig 1 door type sulfur dioxide test chamber Fig 2 hood type sulfur dioxide test chamber 2 Prepare the sample to test the typical sample of coating product according to the corresponding standard The bottom plate is usually (150 x 100 x 1.2) mm polished steel plate After pretreatment, coat the sample according to the specified process, dry or cure, and measure the coating thickness 3 Test step 1) the test equipment shall be installed in the room with clean environment, temperature (23 ± 2) ℃, relative humidity (50 ± 5)% to avoid direct sunlight and strong airflow interference 2) Add (2 ± 0.2) l of distilled water to the tank When heating in the future, the water in front of the tank shall be discharged first and the water shall be added again 3) After introducing the specified amount of sulfur dioxide, start the heating device and raise the air temperature to (40 ± 3) ℃ within about 1.5h, and maintain the temperature until the end of the whole cycle for 8h Then stop heating, open the door or raise the cover to the upper side of the test plate After another 16 hours, take the test plate out of the box for inspection Put the test plate into the box again, and repeat the specified number of test cycles after changing the water Generally, the test cycle is uninterrupted, but in case of interruption, such as holidays, it shall be noted in the record 4) It should be noted that the same amount of sulfur dioxide should be introduced in each test cycle, and the area of the sample plate in the box should be basically the same In contrast test, the total area of the sample plate in the box shall be the same; in case of dispute or key test, the total area of the sample plate shall be (0.5 ± 0.1) M 2 4 At the end of the specified number of test cycles, take the test plate out of the box, wipe the test plate dry with absorbent paper and immediately check whether there are blisters or other signs of damage Open the test plate for 24 hours at room temperature, and then check the adhesion, rust point, discoloration, brittleness or other specified characteristics of the test plate again If the bottom plate needs to be inspected for corrosion, it can be inspected after removing the coating as required After the test, write out the test results according to the corresponding standards 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,
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