I. What is silicone oil?

Silicone oil, also known as polysiloxane, has very stable silicone-oxygen bonds, so silicone oil has good thermal and oxidative stability. Currently, silicone oils used as lubricants mainly include methyl silicone oil, methyl phenyl silicone oil, methyl chlorophenyl silicone oil and ethyl silicone oil.
Methyl silicone oil is generally used as damping fluid and special-purpose grease base oil, ethyl silicone oil is mainly used for precision instrumentation oil.
Methyl phenyl silicone oil is often used to make synthetic high temperature grease base oil due to its high temperature resistance, low freezing point and good oxidation resistance.
Chlorosilicone oil has better lubricity than other silicone oils, so it is often used in the preparation of medium load grease base oil.

II. Silicone fluids in lubrication.

Lubricant defoamer or antifoamer.

Lubricating oil in the lubricating oil system is usually forced circulation mode of operation, operation often into some air, in the case of intense agitation will produce foam and bubbles, larger air bubbles can quickly rise to the surface of the oil, and smaller bubbles rise more slowly. Whichever form exists in the oil will have an adverse effect on the equipment, may make the oil pump oil pressure does not go up and affect the oil circulation, damage to the oil film, wear and tear, while the oil pressure is unstable, affecting the regulation, the bubble by the top of the tank in serious cases of spillage, threatening the operation of the unit, so the oil must be anti-foam properties.

In order to eliminate the working medium in the equipment system work foam, after a long period of observation and research, found a variety of anti-foaming methods, such as physical defoaming method, mechanical defoaming method, chemical defoaming method, etc., of which the chemical defoaming method of adding anti-foaming agent has the best effect, the method is simple, so it has been widely used at home and abroad. 1943 Shell Development Company and the Gulf Coast Research and Development Corporation at the same time found that liquid organic In 1943, Shell Development Company and Gulf Research and Development Company both found that liquid organic polysiloxane is a very effective antifoam agent. Nowadays, methyl silicone oil is still widely used as lubricant antifoam agent.

Precision instrumentation lubricant base oils.

Precision instrumentation, often used in aerospace, diving and other high-tech fields, requiring its long service life, high reliability, can be applied to a variety of harsh environments, precision instruments, bearings, gears and other components within the installation of space is often limited to the weight and power consumption are strictly limited, and the requirements of the neighboring high-precision functional components to match, some of the instrumentation of the work of the environment is relatively harsh, such as aerospace instrumentation in high altitude or Some instruments work in harsh environments, such as aerospace instruments working in high altitude or space, diving instruments working in the deep sea, polar instruments working in the snow and ice, etc.. Want to improve and maintain the performance of precision instrumentation, that precision instrumentation maintenance is essential, and maintenance of the most important is to add lubricant.

Precision instrument oil is a low viscosity synthetic lubricant with excellent viscosity and temperature, and a variety of additives such as antioxidant, rust and corrosion resistant instrument lubricant formulated from low temperature. This precision instrument oil is designed to be used for the life-long lubrication of low-temperature, low-torque, high-precision miniature bearings, gear shafts and slide shafts of precision instruments and timers, with excellent oxidation resistance, anti-wear and low-temperature properties.

Silicone oil is a common base oil used in precision instrumentation lubricants. The silicone-oxygen bonding energy in silicone oil is as high as 1014.2kJ/mol, which makes the silicone oil have excellent thermal stability and oxidation resistance, and ensures that it is not easy to decompose and react at high temperatures, so as to avoid damage to the quality of the oil, and at the same time, the silicone oil also has excellent low-temperature resistance, and the pour point can be lower than -50°C. The viscosity and temperature properties of silicone oil are better than the low-temperature and low-torque lubrication of precision instrumentation.

Silicone oil viscosity temperature performance compared to mineral oil to be more small, viscosity with temperature change is small, so that in the case of temperature change is not much to maintain the same lubricating properties, to protect the accurate operation of precision instrumentation. Silicone oil's stable chemical properties also gives it good anti-rust properties, to protect precision together with the internal parts are not rusted, and silicone oil shelf life is very long, precision instrumentation using silicone oil as lubricant can be used for a long time, reduce the number of replacement.

III. Application of silicone oil in vibration damping.

Silicone fluids are liquid polyorganosiloxanes with excellent high and low temperature resistance, chemical stability, shear resistance, viscous temperature characteristics and high compression ratio. Silicone oil-based vibration damping products are widely used in electrical and electronic equipment, high-rise buildings, bridges and weapons platforms.

Silicone oil viscous temperature coefficient than the carbon chain structure of organic polymers is lower, which is mainly due to the silicone oil molecular chain of silicone oxygen silicon bond bond angle and bonding energy of large, large degree of freedom of orientation, good flexibility. Among the various silicone oils, methyl silicone oil has the smallest temperature viscosity coefficient and the smallest change in viscosity with temperature, so it is most suitable for the base oil of damping fluid.

As the temperature rises, the viscosity of methyl silicone oil in the low-temperature section of the larger changes, while in the high-temperature section of the smaller and smaller changes. Therefore, methyl silicone oil is a damping material suitable for use at higher temperatures. Silicone oil-based damping fluid damping is stable in a wide range of temperature and frequency damping performance. However, in order to further improve the damping performance of silicone oil, it is often necessary to add a certain amount of filler viscosity.

In fact, due to the general molar mass of methyl silicone oil has a certain distribution, is polydisperse, which indicates that the viscosity-temperature coefficient and the distribution of the molar mass is also related to the viscosity-temperature coefficient can be different viscosity of methyl silicone oil formulated with lower viscosity of the required viscosity of methyl silicone oil as a damping fluid base oil. The common viscosity (kinematic viscosity at 25℃) of dimethyl silicone oil used as damping fluid is 1000-10000cs.