Nanometer aerogel insulation
Nanometer microporous aerogel insulation is a new type of material obtained by a series of physical and chemical reactions with SiO2 particles with a diameter of several tens of nanometers, combined with infrared sunscreen and fiber. It contains a large number of nano-scale micropores inside. It has a very low thermal conductivity, thermal insulation performance is 6 to 10 times that of traditional materials (ceramic fiber, calcium silicate, rock wool, etc.), thermal conductivity rises very little in the high temperature range, up to 1200 °C temperature resistance. In order to make the Nanometer microporous aerogel insulation material have good machinability, and also to increase the strength of the material, the Nanometer microporous aerogel material is added with a corresponding proportion of fiber reinforcement and binder. Another important factor is the infrared sunscreen, a mineral oxide powder that allows the Nanoometer microporous insulation to block the movement of infrared light. The heat radiation lost on the surface of the object is proportional to the fourth power of the temperature. When the temperature is above 100 °C, the radiation becomes the main way of heat transfer, and it increases rapidly with the further increase of temperature. The fine particles of the mineral oxidized powder are uniformly dispersed in the nanoporous material, and work by the refraction of the infrared rays on the surface of the particles. In order to achieve an effect optimization, the size of the particles is close to the infrared wavelength.
There are three reasons why the Nanometer hole aerogel superinsulation material has super thermal insulation properties:
1 almost all pores in aerogel material are below 100 nm, so the reflective interface and scattering particles inside the material increase, which greatly reduces the heat radiation absorption capacity and makes the material have excellent thermal insulation performance;
2 Most of the aerogel materials (more than 99%) have pore sizes of less than 50 nm, so that the material is in a vacuum state. The average free motion of the main components of air (nitrogen and oxygen) is around 70 nm. When the pore diameter is 50 nm, the gas molecules in the pore lose the ability to flow freely, and relatively adhere to the pore wall. At this time, the state of the material is similar to the vacuum state, so that the material is at a high temperature or At room temperature, there is a thermal conductivity lower than that of still air;
3 aerogel material has a very low bulk density, and the low bulk density enables the volume of gas inside the material to be large, which is beneficial to improve the thermal insulation properties of the material.