Abstract: This paper compares the sealing effect of medium temperature sealing agent in different manufacturers through the test. At the same time, it introduces the improvement method of the company's medium temperature sealing process, which is to increase the sealing method after adding the hot pure water washing treatment after the medium temperature sealing. Quality, shortened delivery time.
In order to obtain better corrosion resistance, a general aluminum alloy anodized film is subjected to sealing treatment. The sealing process is divided into normal temperature sealing (low temperature sealing), medium temperature sealing, boiling pure water sealing, high temperature steam sealing and the like. Compared with other sealing methods, the medium temperature sealing hole has the advantages of no fluorine, fast sealing speed, no discoloration, low cost, etc., and is used on a large scale in the industry.
According to the requirements of the national standard GB5237.2-2008, the weight loss of the sealing hole after the sealing of the profile is not more than 30mg/dm2 after 120h. The film thickness of photovoltaic aluminum profiles is relatively high (≥15?m). After ordinary medium temperature sealing treatment, it is generally necessary to pass the 120h aging before the sealing weight loss is qualified, which is difficult to meet the delivery requirements. Especially in dry weather conditions (the company's warehouse December, January relative humidity is 40-60%), after the aging time (120h) specified in GB5237.2-2008, it is still difficult to guarantee the weight loss.
In order to explore whether the ordinary medium temperature sealing process in dry environment can guarantee the sealing quality, this paper firstly compares the sealing effect of different sealing agents through experiments. In order to overcome the influence of dry environment, shorten the aging time and improve the sealing quality, the company improved the medium temperature sealing process, that is, increased the hot pure water washing treatment. The optimum conditions of hot pure water washing were determined by orthogonal test.
2 test part
2.1.1 Materials: The substrate is the photovoltaic profile of the alloy grade 6063 produced by the company. The sealing agent is selected from the sealing agent A currently used by the company and the sealing agent HY and sealing agent HH which are well-known brands on the market.
2.1.2 Process: degreasing - water washing - alkali etching - two water washing - neutralization - two water washing - anodizing - two water washing - medium temperature sealing - two water washing.
2.1.3 Process parameters of key processes
220.127.116.11 Anodizing: free sulfuric acid 170g/L, aluminum ion 13.0g/L, bath temperature 18°C, current density 1.3A/dm2, oxide film thickness 18μm.
18.104.22.168 Medium temperature sealing hole: Nickel ion is 1.2g/L, PH value is 5.7, temperature is 55°C, and time is 1?m/min.
2.1.4 Test method: A profile of an anodized line on the production line was cut into 18 pieces of length 5 cm and placed in three different sealing solutions for intermediate temperature sealing test.
2.1.5 Medium temperature sealing test
For objective comparison, the sealing agents A, HY and HH were uniformly formulated into three kinds of sealing solutions according to the process conditions of 22.214.171.124. The above 18 profiles were divided into 3 groups, 6 in each group, and placed in 3 different sealing liquids for 18 min. After the sealing is completed, wash the tap water twice and let it dry naturally.
2.1.4 Sealing weight loss test
After the profile is sealed, store the sample in our warehouse (relative humidity 40-60%). Each group of samples was aged for 2h, 72h and 120h, and then tested for weight loss according to GB/T8753.2-2005 nitric acid pre-dip phosphoric acid method.
2.2 Test 2
2.2.1 Process: According to the 2.1.2 process, finally add a hot pure water wash.
2.2.2 Test method: The profile after anodizing and medium temperature sealing on the production line is cleaned, and 9 pieces of sample with a length of 5 cm are cut out and placed in hot pure water of different temperatures, and one piece is taken at intervals.
2.2.3 Orthogonal test: The temperature and time of hot pure water treatment are used as process parameters. Three different levels are selected for each parameter, and orthogonal test is performed to determine the optimal parameters of hot pure water treatment. The sealing test was performed 2 hours after the sealing was completed.
3 Results and discussion
3.1 Comparison of sealing effect of different sealing agents
In the dry environment, after the different sealing liquid treatment, the sealing weight loss data measured at different aging time are as follows:
In a dry environment (relative humidity of 40%-60%), after 120h aging, the weight loss of the three kinds of sealing solution treated samples did not meet the requirements. After the middle temperature sealing is completed, the profile is generally placed for a period of time, and the moisture in the air is used for aging, and the drying environment slows down the aging. It can be seen that in the dry environment, the ordinary medium temperature sealing process does not guarantee the sealing quality of the high film thickness oxide profile (such as photovoltaic oxide profile).
3.2 Process conditions for hot pure water treatment
Taking the temperature and time of hot pure water treatment as the process parameters, three different levels were selected for each parameter, and the orthogonal test was performed.
It can be seen from the orthogonal test that when the temperature factor is selected as the level 3 and the time factor is selected as the level 3, the sample obtained is the sample 9. The weight loss of the sealing hole is the smallest, but the appearance is gray, and the time is as long as 16 min, and the efficiency is not high. . When the temperature factor is selected as the level 2 and the time factor is selected as the level 2, the obtained sample is the sample 5, and the weight loss of the sealing hole is close to that of the sample 9, and the appearance is not ash. Therefore, we determined that the optimal process parameters for hot pure water treatment are: temperature 70 ° C, time 12 min.
4.1 In the dry environment, the ordinary medium temperature sealing process can not guarantee the sealing quality of high film thickness oxidized profiles (such as photovoltaic oxide profiles).
4.2 Adopting the method of adding hot pure water washing after the medium temperature sealing hole can accelerate the aging, improve the sealing quality and shorten the delivery time.
4.3 The optimum process parameters for hot pure water treatment are: temperature 70 ° C, time 12 min.