Is the minimum 5*10-2 vacuum required by the Ta heating body vacuum heat treatment furnace at high temperature or must it be achieved before heating? As a result of the specific sample, the binder volatilization, furnace at 500℃ around the vacuum will be greatly reduced, this influence is big?
Before heating, the vacuum degree of our tantalum heater is usually very high, easily reaching 10-3pa. During heating, the air will be deflated, and the vacuum degree will decrease, but it will generally maintain to about 2×10-2.
For specific samples, such as samples with adhesives, the furnace cannot be used directly, but must be pretreated with a medium temperature vacuum furnace (rated temperature is about 500-800℃). If the tantalum heater is directly used, it will pollute the tantalum heater or the vacuum degree will not be removed for a long time.
Vacuum furnace is generally preheat diffusion pump 1-1.5 hours, and then began to install the furnace, vacuum, vacuum to meet the requirements, before starting to send electricity heating; Continuous out of the furnace, not at all the diffusion pump. Only when there is no production task temporarily, the vacuum is broken, out of the furnace, the furnace door is closed, the large valve above the diffusion pump is closed, the small valve above the mechanical pump is closed, and the diffusion pump is closed, but the mechanical pump connected with the diffusion pump (this pump is generally called maintenance pump) still needs to work for 1-1.5 hours before it is closed. Of course, there should be no problem with the valve. If the oil in the diffusion pump oxidizes, the high vacuum cannot be pumped up.
