Silicone oil, due to its excellent thermal stability, low volatility and wide temperature range applicability, has become a commonly used heat carrier material in the industrial field. Not all silicone oils are suitable for heat transfer scenarios. They must meet core requirements such as high-temperature resistance, oxidation resistance, and small viscosity-temperature coefficient. Among them, methyl silicone oil, methyl phenyl silicone oil, and ethyl silicone oil are three main types of heat carrier silicone oils. 
Methyl silicone oil is the most basic heat carrier silicone oil. Its main chain is composed of silicon-oxygen bonds, and the side chain is a methyl group. Its usage temperature range is typically from -50℃ to 200℃. It has good chemical stability and electrical insulation properties, and has a low cost, and is widely used in small and medium-sized heating equipment and laboratory reaction vessels for temperature control. However, if used for a long time at temperatures above 200℃, it is prone to thermal decomposition, limiting its application in high-temperature scenarios. 
Methyl phenyl silicone oil improves performance by introducing phenyl groups, significantly enhancing its high-temperature resistance. Its usage temperature can be extended to 250℃ - 300℃, and its low-temperature fluidity is better than that of methyl silicone oil, maintaining good viscosity at -60℃. This type of silicone oil is suitable for high-temperature heating systems in plastic processing, textile printing and dyeing, etc., but excessive phenyl content will lead to an increase in viscosity, and the ratio needs to be adjusted according to specific working conditions. 
Ethyl silicone oil has good high-temperature resistance and radiation resistance. Its usage temperature range is from -40℃ to 220℃. It is widely used in heat transfer systems in nuclear industries, medical equipment, etc. 
When choosing heat carrier silicone oil, it is necessary to consider the working temperature, pressure, and equipment requirements comprehensively. At the same time, regular detection of its viscosity and acid value changes is required to ensure heat transfer efficiency and usage safety.