In "10⁻⁷ torr-level" conventional high-vacuum scenarios such as electron tubes, CRTs, bulbs, capacitors, optical coating, and high-vacuum metallurgy, the selection of diffusion pump working fluid directly determines pumping efficiency, backstreaming rate, and long-term operational stability. Mineral oil diffusion pump fluids have high vapor pressure and easily crack under high-temp jets, unable to stably hold the 10⁻⁷ torr level; while blindly adopting 705-grade UHV silicone oil (viscosity 170-175cSt) brings the burden of "over-selection" with slow start-up, high heating power, and high cost. With escalating demands for "untrapped ultimate vacuum 10⁻⁷~10⁻⁸ torr, 25℃ vapor pressure ≤5×10⁻⁸ torr, 38cSt-class kinematic viscosity precisely matching nozzle jet, flash ≥210℃", sourcing a high-vacuum diffusion pump silicone oil with "single-component pure, tetraphenyl steric shielding, thermal-oxidative dual stability" has become the core gap for domestic conventional high-vacuum manufacturing localization. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches IOTA 704 High-Vacuum Diffusion Pump Oil (Chemical Name: 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane; CAS 3982-82-9; MW 484). Characterized by "colorless transparent oily liquid; viscosity 38±3cSt (25℃); RI 1.5500-1.5600; sp.gr. 1.06-1.07; COC flash ≥210℃; congealing point -35℃; untrapped ultimate vacuum 10⁻⁷~10⁻⁸ torr; 25℃ vapor pressure 5×10⁻⁸ torr; 25kg PE drum or 200kg iron drum; non-toxic non-hazardous transport; 3-year shelf life", backed by "tetraphenyl steric shielding + single-component zero light fraction + 38cSt jet dynamics precise matching", it serves as the "hub of vacuum" for conventional high-vacuum systems, featuring identical chemical structure to Dow Corning 704 (same CAS), enabling import substitution. Molecular Architecture: Tetraphenyl Steric + Single-Component Uniformity + 38cSt Jet Dynamics

• Tetraphenyl Steric Vapor Suppression: Four benzene rings distributed on the siloxane backbone; π-π conjugation combined with large molecular volume synergistically suppress 25℃ vapor pressure to 5×10⁻⁸ torr (extrapolated value ~2×10⁻⁸ torr). Phenyl steric hindrance also suppresses the depolymerization that limits PDMS high-temp performance, enabling 704 to reside long-term without decomposition at typical diffusion pump operating temperatures of 200-250℃.
• Single-Component Zero Light Fraction: 704 is a single-component pure fluid — every molecule in the charge is identical. This means no light fractions can preferentially evaporate; while ordinary blended silicone oils gradually drift in composition as light components escape during long-term use, leading to decaying ultimate vacuum, 704 maintains compositional constancy from the first drop to the last, delivering long-term vacuum stability and predictability far exceeding blended oils.
• 38cSt Jet Dynamics Precise Matching: Viscosity 38±3cSt at 25℃ (about 24cSt at 40℃), this viscosity window is the "golden zone" for diffusion pump nozzle high-speed jet — ensuring stable high-speed vapor ejection and momentum transfer at the nozzle while guaranteeing smooth condensate return, achieving rapid pump-down and high pumping efficiency.

Performance Leap: From "Mineral Oil Coking" to "10⁻⁸ torr Clean High Vacuum"

• High-Vacuum Level: Untrapped ultimate vacuum reaches 10⁻⁷~10⁻⁸ torr, meeting the stringent demands of conventional high-vacuum equipment such as electron tubes, CRTs, optical coatings, and high-vacuum metallurgy.
• Minimal Backstreaming: 25℃ vapor pressure only 5×10⁻⁸ torr; ultra-low vapor pressure leads to minimal backstreaming, and with baffles or cold traps, backstreaming can be further suppressed, ensuring process purity in high-vacuum chambers.
• Thermal-Oxidative Dual Stability Without Coking: Phenyl steric hindrance grants 704 excellent thermal stability and oxidation resistance — even during accidental air leaks while the pump is hot, 704 remains chemically inert, preventing the formation of gums, tars, or hard carbon deposits on jets or pump walls, extending oil life and maintenance intervals.
• Wide-Temp Reliable Start-Up: Congealing point -35℃ ensures start-up reliability in cooler environments; COC flash ≥210℃ provides ample safety margin for various industrial sites.
• Rad-Hard & Flame-Retardant: High phenyl content grants excellent radiation resistance and flame retardancy, suitable for nuclear industry and other high-energy environments.

Application Penetration: From CRT Manufacturing to High-Vacuum Metallurgy

• Electron Tube & Display Industry (Main Battlefield): TV tubes, fluorescent tubes, cathode ray tubes, ordinary bulbs, capacitors, rectifier metallized film vacuum systems — 704's low backstreaming ensures internal high-vacuum purity, preventing efficiency drops or electrode leakage.
• Optical Coating: Anti-reflective coatings, optical filters, mirror surface improvement — provides a clean high-vacuum environment for vacuum coating in the optical industry.
• High-Vacuum Metallurgy: Melting, degassing, and sintering of refractory metals in high-vacuum furnaces — 704's thermal stability ensures oil quality stability during long-term operation above 200℃.
• Research & Accelerators: Atomic energy accelerators, electron microscopes, and other scientific research equipment's high-vacuum systems — single-component pure characteristics ensure long-term constant vacuum.
• High-Temp Carrier & Transmission Fluid: Can function as transmission fluid in high-temperature carriers and various instruments.

IOTA Technical Guide: Moisture-Proof & Light-Proof, 3-Year Long Efficiency

• Application: As diffusion pump working fluid, fill per pump specification; typical boiler temperature 200-250℃; 704's viscosity of 38cSt enables fast start-up and moderate heating power consumption — when process vacuum demand is at the 10⁻⁷ torr level, 704 is the optimal economic choice, no need to blindly upgrade to 705.
• ⚠️ Taboo: Store diffusion pump oil sealed, no mixing with other oils, water, or impurities; immiscible with mineral/ester oils, no blending; avoid contact with oxidants.
• Storage: Store in moisture-proof, damp-proof, sunlight-protected warehouse at indoor temperature -40~50℃; 25kg PE drum or 200kg iron drum; non-toxic non-hazardous transport and storage; 3-year shelf life.
• Handling: Single-component nature ensures compositional constancy during long-term high-temp operation, but regularly check oil level and color; when changing oil, clean the diffusion pump with No. 120 solvent gasoline, dry, and add the specified amount.

Industry Insight: The three core metrics of diffusion pump oil — vapor pressure, thermal stability, and molecular weight — determine the performance ceiling of high-vacuum systems; in conventional high-vacuum (10⁻⁷ torr level) scenarios, blindly adopting UHV oil not only fails to bring linear benefits, but also causes slow start-up, high energy consumption, and cost waste due to excessive viscosity. IOTA 704, with "tetramethyl tetraphenyl trisiloxane + 5×10⁻⁸ torr vapor pressure + 10⁻⁷~10⁻⁸ torr ultimate vacuum + ≥210℃ flash + 38cSt jet dynamics + single-component pure + 3-year shelf life", fills the key supply chain link for domestic high-vacuum diffusion pump oil in electron tube, CRT, optical coating, and high-vacuum metallurgy fields, providing import-substitution for downstream conventional high-vacuum manufacturing enterprises (identical chemical structure to Dow DC 704, same CAS 3982-82-9, priced at approximately 50-60% of Dow's, domestic spot delivery in 3-5 days). This confirms domestic specialty silicone oils are leaping toward "single-component tetraphenyl high-vacuum silicone oil", with growing technical say in high-vacuum media.