SPS pressure sintering furnaceThe full name is Spark Plasma Sintering Furnace, which is an advanced material preparation technology equipment widely used in physics, materials science, aerospace and other fields. It utilizes the discharge plasma generated when pulse current passes through powder particles to achieve rapid sintering of materials. When a pulse current passes through powder particles, electric spark discharge occurs in the air gap between the particles, generating high-temperature plasma. The active particles in these plasmas have high energy, which can promote the decomposition of oxide films on the surface of powder particles, enhance the activity of the powder surface, and promote the contact and bonding between particles. Under the high temperature effect of discharge plasma, the surface of powder particles rapidly heats up to the sintering temperature, and then forms a compact sintered body under external pressure.
SPS pressure sintering furnaceIts detailed operation guide:
1、 Preparation before the experiment
Security confirmation
Wear PPE: Wear heat-resistant gloves, protective goggles, and lab coats.
Environmental inspection: Ensure that there are no debris around the equipment, good ventilation, and normal cooling water, compressed air, and power supply.
Equipment status: Confirm that the furnace has cooled to room temperature and that there are no leaks in the vacuum and hydraulic systems.
Sample and mold preparation
Choose a mold: Select a suitable graphite mold (usually cylindrical) based on the sample size and shape.
Cleaning the mold: Clean the inner wall, upper and lower punches, and pads of the mold with anhydrous ethanol or acetone, remove oil stains and impurities, and air dry or dry.
Sample loading:
Uniformly load the powder sample into the mold cavity.
Use a scraper to level the surface.
Insert the lower punch and add graphite pads if necessary.
Ensure that the mold components (base, mold, punch) are correctly assembled and not skewed.
Equipment inspection
Check if the cooling water flow and temperature are normal (usually requiring a water temperature of<25 ° C and a flow rate that meets the requirements).
Check if the hydraulic oil level is normal.
Check the oil level and color of the vacuum pump, and replace it if necessary.
Confirm that all safety interlock devices (furnace doors, emergency stop buttons) are functioning properly.
2、 Furnace installation and sealing
Load into mold
Carefully place the assembled mold into the furnace, ensuring that it is positioned at the center of the upper and lower pressure heads.
Adjust the position to avoid friction between the mold and the furnace wall or electrode.
Close the furnace door
Slowly and steadily close the furnace door.
Manually or automatically lock the furnace door sealing device to ensure good vacuum sealing.
3、 Vacuum pumping and atmosphere replacement (if necessary)
Activate the vacuum system
Turn on the mechanical pump and perform rough vacuum pumping on the furnace chamber.
When the vacuum degree reaches a certain level (such as<10 Pa), depending on the equipment configuration, it may be necessary to turn on the molecular pump or diffusion pump for high vacuum pumping.
Vacuum degree inspection
Observe the vacuum gauge reading to confirm that the vacuum level meets the process requirements (usually<10 ⁻¹ Pa or higher).
Maintain high vacuum for a period of time and check for any air leaks (whether the vacuum level is stable).
Atmosphere replacement (optional)
If the process requires sintering under an inert atmosphere (such as high-purity Ar):
First, evacuate the chamber to a high vacuum.
Fill the chamber with high-purity inert gas to near atmospheric pressure.
Vacuum again.
Repeat this process 2-3 times (referred to as "displacement") to remove oxygen and moisture to the maximum extent possible.
The last time inert gas is added to the process pressure (usually slightly positive pressure).
4、 Set up sintering program and startup
Activate the control system
Turn on the power supply of the control cabinet and computer.
Start the SPS control software.
Set sintering parameters
Enter or select the preset sintering program in the software interface, with key parameters including:
Heating rate (° C/min)
Target temperature (° C)
Insulation time (min)
Pressure curve: preloading, sintering pressure, holding pressure (kN or MPa)
Pulse current mode (such as DC, pulse ratio)
Vacuum degree/atmosphere pressure setting
Cooling methods (furnace cooling, gas quenching, etc.)
System self-check
Software usually performs a system self-test (checking the status of water, electricity, gas, vacuum, pressure, etc.) to confirm that all conditions are met before starting.
Start sintering program
Confirm that all parameters are correct, click the "Start" or "Run" button.
The system will automatically execute the set program: heating, pressurization, insulation, and cooling.
5、 Operation monitoring
real-time monitoring
Real time monitoring on the control software interface:
Temperature (measured by thermocouple)
Pressure (actual applied pressure)
Displacement (sample densification shrinkage)
Current/voltage (discharge state)
Vacuum degree/atmosphere pressure
Observe whether the curve changes as expected, whether there are any abnormal fluctuations or alarms.
Security duty
During the experiment, operators are not allowed to leave and are always prepared to respond to unexpected situations such as alarms, water leaks, and air leaks.
6、 End of experiment and sampling
Program ends
After the sintering program is completed, the system automatically stops heating and pressurization.
Cool according to the setting (usually takes several hours).
Restore normal pressure
Wait for the furnace temperature to cool down to a safe temperature (usually<100 ° C, refer to the manual for details) before proceeding to the next step.
If a protective atmosphere is used, turn off the gas source first.
Slowly fill the furnace chamber with inert gas or air to atmospheric pressure (to prevent equipment or samples from being damaged by sudden pressure changes).
Open the furnace door
Unlock and open the furnace door.
Take out the sample
Carefully remove the mold using specialized tools such as crucible pliers.
After the mold cools down, use an ejector device to eject the sintered sample from the mold.
Cleaning and Recording
Clean the mold and furnace according to daily maintenance requirements.
Record experimental parameters, sample status, and equipment operation.