What is the cause of the breakage of the ceramic tube of the corundum tube in the microwave tube furnace?

- May 30, 2019-

When the microwave tube furnace uses high-quality characteristics of high-purity and high-temperature, the corundum material has poor thermal shock resistance and is not resistant to rapid cooling and heat. It requires careful operation during our use, and improper operation will only cause the furnace tube. Please also use it carefully.

When using a corundum furnace tube to burn samples to a sample of about 1300 °C, the sample with less water content, crystal water and water content during heating is recommended to pre-burn the sample about 120 degrees before draining the water. Then, put it into the sintering reaction of the corundum furnace tube. The newly purchased furnace tube should be baked at 1300 ° C at a heating rate of 5 ° C / min and then used for work to eliminate stress and pollutants. The heating rate should not be too fast, the heating rate is 5~8°C/min, the limit speed is 10°C/min, and the cooling curve should be set. The heating rate should not be higher than 10°C/min, and the cooling rate should be lower than 10°C/min. Be sure to set the cooling rate. Do not operate the stop program directly at high temperatures.

Do not exceed 140 degrees during the sampling of the sample. The high temperature sample and sampling may cause the corundum tube to break. Do not use the low temperature object to touch the high temperature tube. Remember that the corundum tube should be placed in the tube and placed in the hot zone. The most suitable between the districts. When the atmosphere is required to be passed, the airflow should not be excessive, and 5 to 10 bubbles per minute is preferable, so as to avoid the possibility that the furnace tube may be broken due to the temperature difference of the furnace tube. Use a high temperature corundum furnace tube, preferably with brackets on both sides of the tube to avoid deformation and fracture caused by gravity of the tube.

The temperature difference of the furnace tube is too large, and the temperature rise and temperature drop rate of the high temperature furnace tube is just 5 degrees per minute. The important thing is that the hot and cold rush to send the culprit leads to the important reason for the broken tube of the corundum furnace tube. The use temperature is generally not more than 1650 °C. Keep the inside of the tube clean, clean the inner wall of the tube, and leave no sample in the tube.