Is the minimum 5*10-2 vacuum required for a Ta heating element vacuum heat treatment furnace at high temperature or must be achieved before heating? As a result of the volatilization of the binder due to specific samples, the vacuum degree of the furnace at about 500℃ will be greatly reduced. Is this a big influence?
Before heating, the general vacuum degree of our tantalum heater furnace is very high, which can easily reach 10-3Pa. During heating, the gas will be vented, and the vacuum degree will decrease, but it will generally remain at about 2×10-2.
For specific samples, such as those with adhesives, this furnace cannot be used directly and must be pre-treated using a medium temperature vacuum furnace (rated temperature approximately 500-800℃).
If the tantalum heater is used directly, it will cause pollution to the tantalum heater or the vacuum degree will not be pumped up for a long time.
The furnace temperature should be lowered below 100℃ before opening the furnace. In this way, the tantalum heater is better protected; If the cooling time is too long, argon can be filled at 200 degrees to increase the cooling rate.
There is another question, can occasionally, preheat the diffusion pump first, then open the furnace to load the sample? If the valve is in good condition, does this do much damage to the furnace, especially to the oil in the diffusion pump?
Generally, our vacuum furnace preheats the diffusion pump for 1-1.5 hours, and then starts to install the furnace and vacuum pumping. After the vacuum meets the requirements, it starts to send electricity for heating. Continuous out of the oven, when the furnace, there is no diffusion pump. Only when there is no production task behind, first break the vacuum, out of the oven, close the furnace door, vacuum, close the big valve above the diffusion pump, close the small valve above the mechanical pump, close the mechanical pump, the diffusion pump shut down, but the diffusion pump connected to the mechanical pump (this pump is generally called maintenance pump) still need to work 1-1.5 hours before closing. Of course, the valve should not be faulty. If the oil in the diffusion pump is oxidized, the high vacuum will not be able to be pumped up.
