(August 17, 2026) Domestic special chemical materials enterprises have completed an update and optimization of their new generation benzene-based vacuum diffusion pump oils. These products have been improved in key aspects such as ultimate vacuum level, thermal oxidation stability, and low oil return rates. They can be compared with imported models and provide reliable domestic vacuum media solutions for industries such as vacuum coating, semiconductors, photovoltaics, vacuum smelting, and scientific research experiments.

Vacuum diffusion pump oils are the core working media of oil diffusion pumps. The saturated vapor pressure, thermal stability, and anti-oxidation capabilities of these oils directly determine the ultimate vacuum level, equipment lifespan, and product yield of a vacuum system. They are essential components in high-vacuum systems. With the rapid development of optical coating, HJT photovoltaic cells, and semiconductor thin-film processes in China, downstream customers have higher requirements regarding the purity, service life, and batch stability of these oils. At the same time, problems such as long delivery times and fluctuating procurement costs of imported products continue to become significant issues. As a result, there is a growing demand for high-quality domestic diffusion pump oils.

It is understood that the updated vacuum diffusion pump oil is a colorless, transparent benzene-silicon oil system. Through precise synthesis and purification processes, the content of low-molecular impurities has been reduced effectively. This oil has a very low saturated vapor pressure, does not easily decompose or oxidize under high-temperature conditions, and has excellent control over oil return rates. It can maintain an ultimate vacuum level of 10⁻⁶–10⁻⁸ Pa even during long-term continuous operation. In some cases, combined with a cold trap, even higher vacuum levels can be achieved. The oil has a low freezing point and strong adaptability across a wide temperature range, making it suitable for industrial production equipment and ultra-high vacuum devices in laboratories. It can be widely used in applications such as optical coating, electronic device manufacturing, vacuum smelting, vacuum brazing, electron beam equipment, and high-energy physics research facilities.

Several vacuum coating companies have already conducted small-scale trials with these oils. The continuous operation period of the new generation diffusion pump oil is longer than that of traditional products, and the oil change interval is also extended. This effectively reduces the frequency of equipment downtime and maintenance, and the overall cost of use is optimized, allowing continuous and stable production in mass production lines.

Industry analysts say that in 2026, the domestic diffusion pump oil market is in a phase of transition from “meeting basic needs” to “achieving high-performance capabilities”. High purity, low gas emission, and long lifespan have become essential criteria for entering the market, and the process of domestic substitution is accelerating. However, in high-end ultra-high vacuum conditions, domestic oils still need more long-term operational data to prove their effectiveness. In the future, domestic new material companies will continue to optimize molecular structures, improve their product portfolio of medium- and high-end diffusion pump oils, and develop customized products for semiconductor and aerospace applications. This will further narrow the gap with international leading products.

Industry professionals remind that the selection of diffusion pump oils should be based on the vacuum level of the equipment, operating temperature, presence of a cold trap, and requirements for process cleanliness. Proper cleaning of the pump before changing the oil is necessary to avoid mixing different types of oils, thereby ensuring the long-term stable operation of the vacuum system.