Carbon arc lamp artificial climate aging test is an earlier application of artificial climate aging test method, there are two kinds of open type and sealed type, generally choose the open type carbon arc lamp. The carbon arc lamp mainly passes through the carbon arc formed between two carbon rod electrodes and irradiates the surface of the sample through a flat glass filter. The simulation of carbon arc lamps is poor, and the operation is difficult. The carbon rods are required to be replaced every 48-72h, and the operating cost is high, so it is rarely used now. At present, there is a trend to replace carbon arc light sources with xenon light sources in the world, and it is generally believed that 氤 light sources have better simulation of natural sunlight. The artificial weathering test method of plastic carbon arc lamp can refer to GB/T16422.4, IS04892.4 and ASTMG152, ASrrMG153, of which GB/T16422.4 is equivalent to IS04892.4.
a. Irradiation intensity In the artificial weathering test, the irradiation amount of the light source is the main factor that determines the aging degree of the sample. The greater the irradiation amount, the more serious the aging degree. The radiation intensity is generally specified in the test methods of various countries. Among them, GB/T16422.2 stipulates that the wavelength of the passband between 290-800nm, the radiation intensity of 550w/m2 is selected as the reference value of the exposure test, and it is usually selected The 340nm spectral irradiance intensity is 0.5w/m2·nm as the test irradiance intensity; while the commonly used irradiance intensity of ASTMG155 is 0.35w/m2·nm (340nm spectral irradiance intensity). During the test, the radiation intensity should be set according to the specific requirements.
b. Test temperature and humidity
(1) Test temperature Because the surface temperature of the sample is difficult to accurately measure, the black standard temperature is used as the test temperature. The black standard temperature is similar to the temperature of the dark sample with poor thermal conductivity. The black standard thermometer is placed on the sample holder and tested. It is irradiated by xenon lamp in the same way. There are 2 black standard temperatures for selection in GB/T16422.2: (65±3)℃, (100±3)℃, when the test temperature is high, the heat aging effect of the sample is enhanced, changing the artificial light-based The nature of the climate aging test, in the actual test, the commonly used temperature is (65±3)℃, and the commonly used temperature of AsTMG155 is 63℃. The black standard temperature is different from the temperature of the sample chamber. The former is higher than the latter. The temperature of the sample chamber is generally set to about 40℃. Generally speaking, the temperature of the sample is between the temperature of the sample chamber and the black standard temperature. between.
(2) Test humidity The humidity specified in GB/T16422.2 is (50±5)% and (65±5)%. In the actual test, (65±5)% is generally used as the humidity of the test, and there is no clear stipulation in ASTMC155 Humidity value.
(3) The rainfall in the rainfall cycle test simulates the real rainfall in the atmospheric environment. The rainfall causes the sample to be affected by the alternation of cold and heat, and can wash away the stains on the surface of the sample. Rainfall generally uses deionized water or distilled water to avoid corrosion of equipment. The rainfall cycle specified in GB/T16422.2 is: rainfall 18 minutes/rainfall interval 102 minutes. The common rainfall cycle of ASTMG155 is the same as GB/T16422.2.
a. Sample preparation The sample preparation is determined according to the test requirements, such as testing the mechanical properties, the sample can be made into standard splines by injection, mechanical processing, etc.; the appearance change can directly use the original product as the test sample.
b. Number of samples The number of samples is mainly determined by the test items and sampling period of the samples. For example, for each test item of mechanical properties, there are generally no less than 5 test samples, and at least 1 test sample is generally required for evaluating appearance changes. .
c. Condition adjustment before the test After the sample is prepared, it must be adjusted before it can be put into the aging box for artificial weathering test, otherwise the measured data will be inaccurate. The state of the sample should be adjusted according to the relevant standards of the test material.
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