(September 14, 2026) Domestic silicone-based new material companies have made significant progress in the research and development, as well as the commercialization of vacuum diffusion pump oils. The new generation of high-purity phenylsilicone-based vacuum diffusion pump oils have passed multiple batch tests by customers. Their core performance indicators are comparable to those of international products; they can effectively serve high-vacuum applications such as vacuum coating, semiconductors, optical devices, and scientific analysis instruments, thereby accelerating the process of domestic substitution for high-end vacuum medium materials.

Vacuum diffusion pump oils are essential working media that enable diffusion pumps to achieve high vacuum conditions. They are often referred to as “invisible core materials” in high-vacuum equipment. Such products must have extremely low saturation vapor pressure, excellent thermal stability, and anti-oxidation properties. They should not decompose or form carbon deposits at temperatures above 200°C. Additionally, they need to control the oil return rate to prevent contamination of the vacuum chamber, ensuring the stable operation of delicate processes like coating and deposition. Traditional mineral-based diffusion pump oils easily decompose at high temperatures, producing carbon deposits that can contaminate the components being coated. In contrast, phenylsilicone-based diffusion pump oils do not form carbon deposits at high temperatures and possess strong chemical stability, making them the preferred choice for high-end vacuum processes.

With the expansion of N-type photovoltaic cells, the improvement of optical coating technologies, and the increasing demand for semiconductor equipment, the market for high-purity vacuum diffusion pump oils continues to grow. Industry data shows that the domestic market for vacuum fluids used in high-vacuum applications is experiencing steady growth. Downstream customers are demanding higher standards regarding product purity, batch consistency, compliance certifications, local delivery, and technical support. The situation where high-end pump oils had to be imported in the past is gradually changing.

The domestically produced vacuum diffusion pump oil that has passed testing is a colorless, transparent liquid with extremely low saturation vapor pressure. It provides excellent performance in achieving high vacuum levels. It decomposes little and causes minimal oil return during long-term operation, resulting in a longer service life of the oil. This product can be used with various types of oil diffusers and is widely applied in areas such as optical coating, metal thin film deposition, vacuum metallurgy, electron microscopes, mass spectrometry instruments, and aerospace simulations. It also meets regulatory requirements such as REACH, allowing domestic companies to use it for export purposes.

A person in charge of an optical coating company said that previously, the production line used imported diffusion pump oils, which had long procurement cycles and high inventory costs. After starting to use this domestic vacuum diffusion pump oil, the vacuum level became stable, contamination of the chamber could be controlled, and the oil change interval was similar to that of imported products. As a result, overall operating costs decreased significantly, and supply chain risks were reduced.

Industry experts note that there are two main trends in the development of vacuum diffusion pump oils today: First, high purity, low volatility, and low precipitation become the requirements for entering the high-end market. Downstream manufacturers have stricter requirements for the impurities in the oil. Second, green and long-lasting products are replacing traditional oils. Long-lasting oils can reduce waste oil production, which aligns with the manufacturing industry’s efforts to reduce carbon emissions. In the past, the high-end market was dominated by foreign manufacturers. Domestic material companies continue to work on molecular structure design and ultra-pure refining processes, narrowing the performance gap. Domestic diffusion pump oils are gradually moving from low-end applications to high-value-added fields such as semiconductors and precision optics.

Looking ahead, with continued investment in high-vacuum equipment, thin film processes, and scientific research facilities in China, the market for vacuum diffusion pump oils is expected to expand further. Domestic new material companies will continue to improve product formulations, enhance batch management systems, and provide technical support such as guidance on vacuum system selection and oil maintenance. This will help strengthen the upstream materials sector in the high-vacuum industry, providing reliable vacuum medium solutions for high-end equipment manufacturing and export activities in China.