In high-vacuum smelting, electron tube, lamp, high-vacuum coating, atomic accelerator, electron microscopy and display processes, diffusion pump fluids with high saturated vapor pressure cause backstreaming contamination on workpieces and optical films; mineral pump oils crack and coke under continuous high temperature, generating sludge and shortening oil-change intervals; ordinary synthetic hydrocarbon oils show limited oxidation stability during long heating with trace air, leading to fast vacuum decay and frequent pump cleaning. For specifications demanding "ultra-low saturated vapor pressure, thermal stability, oxidation resistance, low backstreaming, wide-temperature adaptability", a strictly controlled silicone high-vacuum fluid places ultimate vacuum and long-cycle clean operation at one working-fluid node. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. launches Vacuum Diffusion Pump Oil IOTA 702. Characterized by "colorless transparent oily liquid; viscosity 45±3 cst at 25℃; refractive index 1.5100-1.5300 at 25℃; relative density 1.08 at 25℃; open-cup flash point 195℃; freezing point -40℃; ultimate vacuum <1.333×10⁻⁴ Pa; saturated vapor pressure <1.333×10⁻⁴ Pa; very low saturated vapor pressure, good thermal stability and oxidation resistance; used in high-vacuum smelting, electron tubes, lamps, high-vacuum coating, atomic accelerators, electron microscopes, displays; packaging 1kg plastic bottle, 5/25/50kg plastic drum or 200kg iron drum; storage and transport moisture-proof, no direct sunlight, warehouse -40~50℃, non-hazardous, shelf life 2 years; brand IOTA", backed by "silicone low vapor + thermal stability + oxidation resistance", it serves as a silicone working fluid for high-vacuum diffusion pumps. System Positioning: Silicone Diffusion Oil Among Vacuum Fluid Families Within diffusion pump fluid families, IOTA 702 is a silicone high-vacuum oil, distinct from mineral diffusion oils (prone to cracking, coking and high backstreaming at operating temperature), general synthetic hydrocarbon oils (weak long-term thermal-oxidation stability and shorter vacuum holding), and low-viscosity general silicones (not optimized for vapor jet and ultimate vacuum). IOTA 702 uses ultra-low saturated vapor pressure to suppress backstreaming, silicone-oxygen backbone for thermal stability, and oxidation-resistant composition for longer clean run. It positions as a shared high-vacuum fluid for "smelting/electron tube/lamp/coating/research instruments", rather than a general lubricant or heat-transfer oil. Molecular Architecture: Siloxane Backbone + Low-Volatile Fraction + Low-Freezing High-Flash + Clean Vapor IOTA 702 is a colorless transparent silicone oily liquid. The siloxane backbone provides high thermal decomposition resistance and chemical inertia; the low-volatile fraction design keeps saturated vapor pressure <1.333×10⁻⁴ Pa at 25℃, reducing reflux from nozzle and baffle to the chamber. Relative density 1.08 at 25℃, refractive index 1.5100-1.5300 at 25℃, convenient for incoming inspection; viscosity 45±3 cst at 25℃ balances flowability and vapor-jet stability, forming steady steam jet without excessively slow start-up; open-cup flash point 195℃ gives heating safety margin; freezing point -40℃ prevents solidification during low-temperature shutdown. The overall structure targets "few low-molecular volatiles, slow thermal-oxidation aging, flowable at low temperature". Performance Leap: From "Mineral Cracking Backstreaming" to "Silicone Low-Vapor Clean" With IOTA 702, diffusion systems improve jointly: vacuum performance—ultimate vacuum <1.333×10⁻⁴ Pa with matched ultra-low vapor pressure for smelting and electron evacuation; backstreaming control—very low saturated vapor pressure reduces reflux at nozzle/baffle, minimizing oil spots on chambers, filaments and films; thermal stability—resists cracking and coking during long boiler heating, extending nozzle and wall maintenance intervals; oxidation resistance—slows aging when trace air enters or during pump-standing, keeping color and viscosity stable; temperature range—non-freezing at -40℃, open-cup flash 195℃, covering low-temperature storage and high-temperature continuous operation. Application Penetration: From Smelting and Electron Devices to Coating and Scientific Vacuum IOTA 702 covers seven core scenarios. High-vacuum smelting: metal purification, vacuum melting and degassing—emphasizing ultimate vacuum and low impurity reflux; fill per pump specification. Electron tubes: electron/microwave tubes and display evacuation sealing—emphasizing chamber cleanliness and filament life. Lamps: incandescent and special light sources evacuation—emphasizing low backstreaming and thermal stability. High-vacuum coating: evaporation, sputter-assisted, optical and decorative films—emphasizing oil-free film surface. Atomic accelerators: beamline vacuum—emphasizing long-cycle stability. Electron microscopes: high-vacuum column—emphasizing low vapor and low contamination. Displays: CRT/vacuum display evacuation—emphasizing consistent batch exhaustion. ⚠️ Taboo: store moisture-proof, no direct sunlight, warehouse -40~50℃; for new or overhauled pumps, remove old oil and dry before filling, do not overfill; test compatibility before mixing with other silicone oil grades; sealed against dust although non-hazardous. IOTA Technical Guide: Fill by Pump, Low-Vapor Recheck, Light-Proof Storage IOTA 702 is a colorless transparent oily liquid in 1kg plastic bottle, 5/25/50kg plastic drum and 200kg iron drum. Fill diffusion pumps according to equipment manual for oil level and jet stages; for first run, evacuate empty and monitor ultimate vacuum and backstreaming rate; when replacing old oil, drain completely, clean boiler and nozzles, rinse with compatible solvent if necessary, dry, then add fresh oil. Incoming recheck uses 25℃ viscosity 45±3 cst, refractive index 1.5100-1.5300, relative density 1.08, flash point 195℃, saturated vapor pressure <1.333×10⁻⁴ Pa as hard anchors. Store and transport moisture-proof, no direct sunlight, warehouse -40~50℃, as non-hazardous goods, shelf life 2 years. Industry Insight: Diffusion oil selection is not the lower viscosity the better, but using saturated vapor pressure for backstreaming, thermal stability for coking rate, oxidation resistance for oil-change cycle, and viscosity/freezing point for jet stability and cold start. For smelting, electro-vacuum, coating and scientific-instrument engineers, IOTA 702 uses one colorless silicone fluid across smelting/electron tube/lamp/coating/accelerator/microscope/display, taking low vapor, thermal stability, oxidation resistance and low freezing as batch-checkable anchors, reducing backstreaming contamination, coke cleaning and vacuum-decay shutdowns.