The production process of high-purity silicon nitride powder:
A) Sieving the metal silicon powder, removing sundries and block, put silicon powder on stainless steel trays, placing it into an oven, set the oven temperature to 70-90 degrees, drying for 7-9 hours.
B) Loading the dried metal silicon powder into a box, make it uniform and flat, placing the box into a silicon nitride reaction furnace, closing the furnace door, vacuuming, reach the set vacuum, stopping the vacuum pump. Then start heating, the initial set temperature is 950-1050 degrees, and the heating time is set for 5-7 hours.
C) Carefully observe the change of the pressure gauge. If there is no change in the pressure gauge within 1 hour, raise the temperature by 10-50 degrees, and then observe the pressure gauge. If the pressure drops, indicates that the metal silicon powder and nitrogen in the reaction furnace start to react. In the first temperature range of 1000-1200 degrees, the reaction time is 22-26 hours.
D) After more than 20 hours, the pressure increased, indicating the end of the first stage of reaction, then continue to raise the temperature up 40-60 degrees, the following heating process is the same as the previous, and finally, the heating ends at 1360 degrees.
E) When the temperature is 1360 degrees and after 4-5 hours, the whole reaction process can be considered to be finished when nitrogen is no longer absorbed. In order to ensure that the product has low free silicon, heat preservation is needed for 9-11 hours.
F) After heat preservation, turn off the power of the furnace and let it cool down. when the furnace temperature drops to 200 degrees, open the furnace door, take out the products, take samples for inspection.
Technical Specifications |
|
|
Chamber size
|
200x200x200mm (Width * Height * Depth) (8 Liter) Can Be Customized
|
|
Max. temperature
|
1700 C (<2hour)
|
|
Working temperature
|
1600 C
|
|
Temperature controlling
|
● PID automatic control via SCR (Silicon Controlled Rectifier) power control with phase angle fired, current limiting resistor.
|
|
● 51 programmable segments for precise control of heating rate, cooling rate, and dwell time.
|
|
|
● Built-in PID Auto-Tune function with overheating & broken thermocouple broken protection.
|
|
|
● Over-temperature protection and alarm allows for operation without an attendant.
|
|
|
Temperature accuracy
|
±1C
|
|
Temperature Uniformity
|
±5C over 120mm @ 1600C
|
|
±3C over 80mm @ 1600C
|
|
|
Heating rate
|
0-20C /min
|
|
Thermocouple
|
B type
|
|
Heating element
|
Quality Mosi2 Heating Elements
|
|
Vacuum
|
0.007 Pa (Molecular pump)
|
|
Furnace Chamber
|
Two layers of ceramic fiber insulation materials
|
|
● First layer: 1800°C ceramic fiberboard.
|
|
|
● Second layer: 1650°C ceramic fiberboard.
|
|
|
Furnace structure
|
Double layer steel casing with dual cooling fan, surface temperature below 60C
|
|
Furnace door
|
● Front-side open
|
|
● Power cutting off when furnace door open
|
|
|
Working voltage
|
220V, 50HZ
|
|
Rated power
|
7KW
|
|
Stander chamber size (mm)
|
100x100x100 120x120x130 150x150x150 150x150x200 200x200x200 200x200x300 250x250x300 300x300x300
300x300x400 350x350x500 400x400x400 450x450x450
500x500x500 600x600x600 800x800x800 900x900x900
|
Note: Other Chamber sizes can be customized.
