Selected fabrics was cut into 15 × 15 cm square, into a beaker of acetone solution, in ultrasonic instrument for cleaning for 30 min, followed by deionized water cleaning 3 - 5 times to basically smell the irritating smell. Then clean the fabric into the oven at 100 degrees 30 min or so, until the fabric weight is not changed. In order to make the sputtering film and substrate material have a better combination, the dry fabric with plasma machine for processing, in order to remove some impurities on the original, and finally iron will be smooth.

The fabric is fixed on the working table of the magnetron sputtering coating machine, the closed chamber is closed and sealed. The mechanical pump is opened, and the molecular pump is pumped to 5.0 × 10⁻⁴ Pa, and the chamber is heated to the setting temperature, and the thermal equilibrium time is 1800 s. After the temperature is stable, high purity argon (concentration of 99.99%), and adjust the preset pressure, a 200W DC power supply for the first 3 min pre sputtering and remove the baffle of sample sputtering time. This process samples always to min speed rotation to keep the sputtering uniformity (the selected experimental parameters are after a lot of experiments using orthogonal experiment was used to optimize the parameters, seeing Table 1). After sputtering, close the DC power supply, and open the pump and the mechanical arm of the pump and the mechanical arm to clean the cavity chamber of the gas (pumping time at least 6 min). After the chamber temperature dropped to 80 degrees Celsius, close the pumping gas channel, open the gas valve (time 3 min) to get rid of the chamber vacuum, open the chamber to remove the specimen.

The surface appearance of the prepared sample with S-3400N scanning electron microscope, the resolution of the scanning electron microscope is 4 nm, the magnification is 30000 times, and the accelerating voltage is 5 kV - 15 kV. X’PERT por type X-ray diffraction were used to characterize the film crystal structure, test conditions for Cu Target K alpha, the Ni filter, tube voltage 40 kV, tube current 40 mA, determination of wavelength lambda = 0.15418 nm, sweep range is 2 theta (5 DEG to 90 DEG), scanning speed for 0.8 sec/step. Japan Shimadzu Corporation UV-3600 UV-vis-IR spectrophotometer, μm film in 0.5 radiation in the wavelength range of reflectivity test using United States Thermo Nicolet’s AVATAR370 FTIR spectrophotometer, the sample wave

number in 400 - 4000 cm⁻¹ (2.5 - 25 μm wavelength) tested the reflectivity. ATR, the samplers are OMNI- SAMPLERTM, scan 32 times, data interval is 1.929 cm⁻¹, and the resolution is 8 cm⁻¹.

Aramid fabrics with improved process parameters on single layer of aluminium sputtering thin film and its surface as shown in Figure 1(a), Figure 1(b); Al thin films in air is a highly oxidizing substance, to improve the heat reflective aluminum film effects, well plated aluminum top layer and SiO₂ is protected, its surface as shown in Figure 1(c), Figure 1(d); three-layer membrane structure morphology of SiO₂/Al/SiO₂ as shown in Figure 1(e), Figure 1(f).

From the 2 K SEM which can be seen in the figure, on the whole, three kinds of coating process on the fiber surface forming a dense homogeneous membrane structure. And it could be seen most single-layer membrane structure of Al surface smooth, mirror-like effect; double SiO₂/Al surface although smooth but granular is also significantly bigger. From 10 K SEM figure you can see that single layer of Al film surface for Al small spherical particles, even thin film is formed on the surface, we can see that Al-membrane structure formation can be used to form a mirror effect to anti-thermal radiation requirements. SiO₂/Al bilayer surface particle becomes large, flat geometry and particle shape, surface flatness is better. Three SiO₂/Al/SiO₂ surface layer of SiO₂ is grainy, but its size gets bigger. Poor smoothness of the film than the other two, there are several points in the larger agglomeration.

In general, all three kinds of membrane structure on the fiber surface forming a continuous dense film structure. Viewed from the surface, single film of Al the most smooth, metal fine particles on the surface; SiO₂/Al bilayer surface is smooth but larger particle size than single-layer membrane. Three layers of SiO₂/Al/SiO₂ surface roughness decrease, and in some places the phenomenon of particle agglomeration.

Figure 2 shows the three kinds of XRD diagrams of structural films. It can be clearly seen from the three film structure, 2θ respectively for, 38.51˚, 44.75˚, 65.11˚, it has obviously peak after and elemental aluminum of standard (JCPDS cards 652869) compared, respectively for Al corresponds to of (111), (200), (220) three a features peak, 78.29˚ at has weaker of Al (311) of features peak, description three species film structure in the are contains metal Al of components. By XRD analysis, Scherrer, Paul formula calculates the average grain size of Al film. Scherrer, Paul formula, where D is the average grain diameter and λ is the wavelength of x-diffraction, β is the most intense diffraction peak FWHM, in radians, and θ is the diffraction angle. Computed in single layer of Al film Al an average particle size of about 28 nm; SiO₂/Al two-layer membrane structure of the average particle size is also about to 28 nm; SiO₂/Al/SiO₂ film structure characteristic peaks in the first three Al calculated an average particle size of about 29 nm. As can be seen in different film structure, little has changed of Al particles with an average diameter. Target interface in the coating process on different surface coating process of particles in particle size has not changed. In 15˚ - 35˚ between the main diffraction peak is the outer layer of SiO₂.

From Figure 5 you can see that after magnetron sputtering coating fabrics in varying degrees of temperature difference between before and after the upgrade, suggests lining heat insulation and heat radiation performance improves. Among them, Al single layer and three-layer SiO₂/Al/SiO₂ fabric side eventually reached 11 degrees Celsius temperature difference showed better protection against heat radiation performance. SiO₂/Al bilayer sides fabric fabric temperature stable at 6˚C instead of coating aramid fabric around the same temperature.