Common Causes of Insufficient Diffusion Pump Vacuum

In processes such as vacuum coating, vacuum smelting, and electronic device manufacturing, diffusion pumps are the core equipment for achieving high-vacuum environments. When a diffusion pump fails to reach its ultimate vacuum level or experiences reduced pumping efficiency, the performance of the working medium—the diffusion pump oil—is often the first thing to check. Under prolonged high-temperature operation, pump oil may undergo thermal decomposition, oxidation, or volatilization, causing its saturated vapor pressure to rise and thereby limiting the ultimate vacuum the system can achieve. Additionally, oil contamination or mismatched oil grade can directly affect the pump's normal operation. Therefore, selecting a diffusion pump oil with stable performance and low saturated vapor pressure is one of the key steps to resolving vacuum level issues.

IOTA 704: Designed for High-Vacuum Applications

IOTA 704 is a pump oil specifically designed for high-vacuum diffusion pumps, with its core advantages being an extremely low saturated vapor pressure and excellent thermal stability.

• Extremely Low Saturated Vapor Pressure: The saturated vapor pressure of IOTA 704 is below 2×10⁻⁸ Pa. This enables diffusion pumps to achieve an ultimate vacuum of 10⁻⁷ to 10⁻⁸ Pa, meeting the requirements of most high-vacuum processes.
• Excellent Thermal Stability: In the continuous high-temperature heating environment of diffusion pumps, thermal stability of the pump oil is critical. IOTA 704 offers excellent oxidation resistance and thermal stability, maintaining stable performance during long-term operation and reducing vacuum degradation and pump chamber contamination caused by oil decomposition.
• Reliable Physical Properties: It has an open-cup flash point of ≥210°C and a pour point of -35°C, allowing stable operation across a wide temperature range. Its viscosity at 25°C is 38±3 cSt, ensuring good fluidity and sealing performance.

Wide Range of Applications

Thanks to its stable performance, IOTA 704 is widely used across multiple industries and equipment that require high-vacuum environments.

• Vacuum Metallurgy & Materials Preparation: Used in high-vacuum smelting, vacuum sintering, vacuum heat treatment, and other processes.
• Optical & Electronic Coating: Used as a working medium in vacuum coating machines for producing optical lenses, decorative coatings, tool hardening films, and more.
• Electronics & Display Device Manufacturing: Used in the evacuation and encapsulation processes of electron tubes, light bulbs, displays, and other devices.
• Scientific Research Equipment: Suitable for high-end research instruments such as atomic energy accelerators, electron microscopes, and mass spectrometers.

Technical Specifications

表格

Parameter	Value
Appearance	Colorless or transparent liquid
Viscosity (25°C)	38±3 cSt
Relative Density (25°C)	1.06~1.07
Refractive Index (25°C)	1.5500~1.5600
Flash Point (Open Cup)	≥210°C
Pour Point	-35°C
Ultimate Vacuum	<10⁻⁷~10⁻⁸ Pa
Saturated Vapor Pressure (25°C)	<2×10⁻⁸ Pa

About IOTA

As a "full-chain silicone solutions provider," Anhui IOTA Silicone Oil Co., Ltd. is committed to providing customers with full-process technical services, from selection consulting to application support. IOTA 704 is one of our key products for high-vacuum applications. If you are looking for a stable working medium for your diffusion pump, IOTA 704 is a choice worth considering. For detailed Technical Data Sheets (TDS), Safety Data Sheets (SDS), or application consulting, please visit our website or contact our technical team.

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FAQ

My diffusion pump can't reach the target vacuum — which oil should I switch to?
We recommend checking and replacing the diffusion pump oil with one that has a lower saturated vapor pressure. IOTA 704 has a saturated vapor pressure below 2×10⁻⁸ Pa and can help diffusion pumps achieve an ultimate vacuum of 10⁻⁷ to 10⁻⁸ Pa. What is the saturated vapor pressure of IOTA 704?
At 25°C, the saturated vapor pressure of IOTA 704 is below 2×10⁻⁸ Pa. Which equipment is IOTA 704 suitable for?
It is suitable for diffusion pumps that require high-vacuum environments and is widely used in vacuum coating machines, vacuum smelting furnaces, electron microscopes, atomic energy accelerators, and other equipment. How is the thermal stability of this pump oil?
IOTA 704 has excellent thermal stability and oxidation resistance, making it suitable for long-term use in diffusion pumps that require sustained high-temperature heating, helping to reduce oil decomposition. What are the flash point and pour point of IOTA 704?
It has an open-cup flash point of ≥210°C and a pour point of -35°C, offering a wide operating temperature range. What is the viscosity of IOTA 704?
At 25°C, its kinematic viscosity is 38±3 cSt. What packaging sizes are available for IOTA 704?
It is available in 1 kg plastic bottles, as well as 5 kg, 25 kg, 50 kg plastic drums, and 200 kg iron drums. Is IOTA 704 a hazardous material? What are the transport and storage requirements?
IOTA 704 is transported and stored as a non-hazardous material. It should be stored in a moisture-proof warehouse away from direct sunlight, with a storage temperature range of -40°C to 50°C. What is the shelf life of IOTA 704?
Under the specified storage conditions, the shelf life is 3 years. How can I obtain technical documentation for IOTA 704?
You can visit the Anhui IOTA Silicone Oil Co., Ltd. website or contact our technical team to obtain the complete Technical Data Sheet (TDS) and Safety Data Sheet (SDS).

Silicone Diffusion Pump Oil IOTA 704 （Replacement for DC704）-IOTA