High purity alumina furnace tube, while taking advantage of its high purity, high temperature resistance, good denseness and other quality characteristics, we must follow the inherent characteristics of corundum material: poor thermal shock resistance, can not be rapid cold and rapid heat. Therefore, in the use of our microwave high-temperature furnace, we need to operate carefully, improper operation can cause the tube or crucible to blow up, analysis of its main reasons are as follows.
1, in the use of microwave high temperature furnace tube heating and cooling speed is best to control 5 ℃ / min, the slower the better. Rapid cooling and rapid heating is one of the main causes of corundum furnace tube breakage, the use of a section of temperature do not exceed 1650 ℃.
2, please always keep the furnace clean, clean the inner wall of the furnace tube in time after use, do not leave some samples in the tube, in order to avoid chemical reactions, causing corundum tube cracking.
3, in the release and sampling, the temperature should not be higher than 150 ℃, and should be slowly from the edge to the center. High temperature sample delivery and sampling is the main cause of corundum tube fracture, shall not touch the high temperature of the furnace tube with low temperature objects.
4, in the need to pass the flow of atmosphere, gas flow from low temperature on the ventilation, gas flow control smoothly, the atmosphere according to the diameter of 10mm bubble 5 ~ 10 / min is appropriate. Avoid excessive cold gas flow, resulting in a large temperature difference between the furnace tube, making the furnace tube fracture.
5, corundum tube in use to place a thermal plug in the tube, the location is the location of the insulation layer. Do not forget to place, easy to cause the furnace body over temperature or furnace tube temperature difference is too large, the furnace tube fracture.
6, must use strong absorption of microwave material boat for experiments. Temperature measurement needs to be inserted into the thermocouple inside or near the material boat, shall not pass into the oxidizing atmosphere for experiments. To avoid inaccurate temperature measurement, resulting in the furnace tube heating too fast and cracking.
7, the sample burned in the corundum tube, especially the sample to be burned to about 1300 ℃, the water content should not be too much. Prevent water vapor condensation leads to corundum tube temperature difference and cracking.
8, the newly purchased corundum tube for the first time to burn high temperature, it is recommended that the heating rate of 5 ℃ / min, heating up to 1300 ℃, insulation 30min to eliminate stress and contaminants.
9, cooling corundum tube should not be too fast, especially when using microwave high-temperature tube furnace, do not use manual and constant temperature mode temperature control, just use automatic mode temperature control, set the temperature rise process, while setting the cooling curve when cooling to 600 ℃. 600 ℃ below can be natural cooling.
10、In order to ensure the service life of corundum tube and about products in microwave high temperature equipment, it is recommended to use the following heating rate.
Below 500℃≤5℃/min.
500℃-800℃≤10℃/min.
800℃-1000℃≤5℃/min.
1000℃-1400℃≤3℃/min.
1400℃-1600℃≤2℃/min.
The above suggestions are for reference only, you still need to choose the suitable method to use corundum furnace tube and corundum crucible and other products according to the specific situation, if you need corundum furnace tube and corundum crucible and other products, welcome to contact us. www.ceramicpartsindia.com