How it works:
By simulating the ultraviolet, visible and infrared parts of the solar spectrum, combined with the control of environmental parameters such as temperature, humidity and spraying, the xenon lamp aging chamber accelerates the aging effect of outdoor natural climate on materials in the laboratory. Its core component is a xenon arc lamp, whose spectral energy distribution is adjusted by a filtered light system to approach natural daylight. The specimens are exposed to set light irradiance, box temperature, blackboard temperature, relative humidity and periodic water spray conditions to evaluate the photostability and weather resistance of coatings and other materials.
Key parameters:
Testing the weathering resistance of coatings requires systematic control of several key parameters. Light irradiance is a core parameter that is usually set and controlled at specific wavelengths (such as 340nm or 420nm) according to standards. The temperature parameters include the cabinet air temperature and the blackboard temperature, which is closer to the actual temperature of the specimen surface. Humidity is usually controlled as a relative humidity percentage. The spray cycle simulates rainwater scouring or thermal shock effects. The comprehensive setting of these parameters needs to be selected according to the purpose of the test and relevant standards.
Test methodology
A series of standard systems have been formed for coating weathering testing at home and abroad, providing standardized procedures and evaluation basis for testing. Common standards mainly include ISO, ASTM and GB series. The test method is usually divided into multiple cycle modes such as continuous light, light and periodic spraying, and light and darkness and spraying to simulate different actual environmental conditions. Test intervals can range from hundreds to thousands of hours, depending on the expected life of the coating and the level of severity of the test.
Performance evaluation
After the coating specimen undergoes the aging test for a specified period, its performance changes need to be quantitatively evaluated. The evaluation items mainly include appearance changes and physical and chemical properties. Appearance evaluation is usually quantified with the help of colorimeter and gloss meter, and combined with visual inspection to evaluate the grades of powdering, cracking, blistering, and peeling. The physical and chemical properties can test the changes in mechanical properties such as adhesion and hardness. The performance retention rate can be calculated by the following formula: Performance Retention = (Aging Performance Value / Initial Performance Value) × 100%. By systematically analyzing these data, the durability of coatings in actual use environments can be scientifically predicted.
Notes:
When using a xenon lamp aging chamber for testing, it is important to ensure that the exposure conditions in all areas are uniform, and the filters and lamps are regularly cleaned to ensure spectral stability. The test results should clearly indicate the standards and specific test conditions on which they are based. It is important to recognize that laboratory accelerated aging testing is a simulation and reinforcement of major climate factors, but due to the complexity and variability of natural climates, the test results may be correlated with actual outdoor exposure results rather than fully equivalent. Therefore, the test data should be used as an important basis for the comparison and screening of material weathering resistance levels, and combined with the actual outdoor exposure data for comprehensive judgment.
Reference article
International Organization for Standardization. Colored paints and varnishes Artificial climate aging and artificial radiation exposure to filtered xenon arc radiation. ISO 16474-2
American Society for Testing and Materials. Standard practice for exposing coatings and related materials using a filtered xenon arc lamp device. ASTM D7869
National Standardization Administration of China. Colored paints and varnishes Artificial climate aging and artificial radiation exposure to filtered xenon arc radiation. GB/T 1865