Diffusion Pump Oil Selection Guide: Five Core Performance Factors Determine Vacuum System Efficiency
Nov 25, 2025
In the field of vacuum technology, diffusion pumps, as core equipment for achieving high and ultra-high vacuum, are highly dependent on the quality of the pump oil used. A high-quality diffusion pump oil is not only crucial for efficient pumping but also the cornerstone for ensuring the long-term stable operation of the system. With modern industry placing increasingly stringent demands on vacuum environments, especially in high-precision fields such as semiconductor manufacturing, precision coating, and scientific research, the choice of pump oil directly impacts the success or failure of production processes and the operating costs of equipment. So, what kind of diffusion pump oil can truly meet these stringent industrial requirements? It must possess extremely low saturated vapor pressure, excellent thermal stability, suitable viscosity characteristics, high safety indicators, and good chemical inertness. These performance indicators collectively determine the pump oil's performance in high-temperature, high-vacuum environments and directly affect the pumping efficiency, ultimate vacuum level, and service life of the entire vacuum system.
In industrial applications requiring high vacuum environments, the choice of diffusion pump oil directly impacts the performance of the entire system. As the "blood" of the vacuum system, high-quality pump oil must simultaneously meet several stringent technical requirements to ensure long-term stable operation of the equipment.
An ideal diffusion pump oil should possess the following five key characteristics:
Guarantee of Ultimate Vacuum: Ultra-Low Saturated Vapor Pressure
The pump oil's saturated vapor pressure at 20°C must be below 10⁻⁸ Pa. This directly determines the ultimate vacuum level the system can achieve. The lower the saturated vapor pressure, the less oil molecules escape into the vacuum chamber, effectively preventing oil vapor contamination and ensuring higher vacuum quality.
The Foundation of Durability: Excellent Thermal Stability
At operating temperatures exceeding 200°C, the pump oil must maintain a stable molecular structure, without decomposition or cracking. High-quality pump oil effectively resists high-temperature degradation, preventing the formation of light components and sludge deposits, thus preventing oil circuit blockage and pump body contamination, ensuring long-term stable pumping performance.
The Balance of Smooth Operation: Just the Right Viscosity
Vitality selection requires a precise balance: too high a viscosity leads to insufficient flow, affecting oil return efficiency; too low a viscosity may cause poor sealing and vapor backflow. The ideal viscosity range ensures smooth flow while maintaining effective vapor sealing.
The Line of Defense for Safe Operation: High Flash Point and Ignition Point
A high flash point and ignition point provide crucial protection for operational safety. This characteristic is especially important in the event of accidental exposure to air, significantly reducing the risk of fire and ensuring the safety of personnel and equipment.
Guardian of Stable Performance: Excellent Chemical Inertness
Pump oil should possess excellent chemical stability, not reacting with common gases in the system (such as air and moisture) or other potentially introduced chemicals. This characteristic ensures that the pump oil maintains stable performance even under complex operating conditions.
With the continuous development of industrial technology, the requirements for vacuum systems are increasing. A proper understanding and evaluation of these key performance characteristics of diffusion pump oils not only helps in selecting suitable products but also provides strong support for improving production efficiency and ensuring equipment lifespan. Users are advised to focus on these technical parameters when purchasing to ensure optimal system performance and return on investment.
