In spacecraft design, every gram of weight means higher launch costs. Multi layer thermal insulation components (MLI) are the core means of passive thermal control for spacecraft - by stacking dozens of aluminum plated films, they maintain the normal operating temperature of internal equipment in the extreme temperature difference environment of space.

The traditional MLI reflective layer uses a 25 μ m or thicker aluminum coated PI film. When engineers reduce the substrate thickness from 25 μ m to 7 μ m, the amount of polymer material used can be reduced by about 72% under the same area. For a satellite containing dozens of layers of MLI, this weight reduction directly translates into an increase in payload or a decrease in launch costs.

2、 PI Al: Material Collaboration in Extreme Environments

The performance advantage of 7 μ m PI aluminum plated film comes from the deep synergy between PI substrate and aluminum coating at the material level.

3、 Vacuum evaporation: "growing" optical grade aluminum layer on 7 μ m substrate

The aluminum layer preparation of 7 μ m PI aluminum coating film adopts vacuum evaporation process - in a vacuum environment, high-purity aluminum wire or aluminum block is evaporated into gas by heating, and then deposited on the surface of PI film to form a coating. This process requires precise control of parameters such as vacuum degree, evaporation temperature, and evaporation rate to ensure the quality and thickness of the coating.

Vacuum deposition on ultra-thin substrates with a thickness of 7 μ m faces a series of technical challenges that are far more stringent than conventional thickness substrates:

4、 Aluminum layer thickness: fine control from 0.1 μ m to 1 μ m

Based on a 7 μ m PI substrate, aluminum plated film products with different aluminum layer thicknesses can be prepared by precisely controlling the evaporation process parameters. The thickness of the aluminum layer (characterized by optical density OD value) varies from 0.1 μ m to 1 μ m, and different thicknesses correspond to different performance focuses:

Note: The thickness of the aluminum layer is the nominal reference value, and the specific performance is subject to the actual product specifications.

5、 Key performance: Technical confidence of 7 μ m specification

6、 Three major application layouts: from spacecraft to precision optics

7、 Selection considerations: from substrate thickness to coating specifications

8、 Conclusion

The essence of 7 μ m PI aluminum plated film is an engineering product that combines the extreme thinning of PI film with optical grade aluminum plating process. It is not simply "thinning" - at the 7 μ m scale, the thermal management, tension control, vacuum evaporation parameters, and coating uniformity of materials are facing new engineering boundaries. It is precisely these boundary conditions that have been overcome one by one - through precise vacuum evaporation process control, surface activation treatment, and high-temperature adhesion verification - that enable the 7 μ m PI aluminum coating to move from the laboratory to mass production, becoming the core material for high-end applications such as spacecraft thermal control, flexible electromagnetic shielding, and precision optics.

For engineers, understanding the process constraints and performance opportunities behind the thickness of 7 μ m - the extreme temperature resistance of PI, the optical reflection characteristics of aluminum, and the performance trade-offs of different aluminum layer thicknesses - is more valuable than simply remembering a specification.