Sponge absorbing materials applied on ships

Sponge absorbing materialWith polyurethane foam as the carrier, soaked with absorbents and flame retardants, it becomes a wave absorbing material. It has the characteristics of good wave absorbing performance, strong flexibility, easy cutting and molding, and is the most historic type of wave absorbing material.

Good absorption performance: assuming the reflection loss of the absorbing material is R, whenAbsorbing materialWhen the thickness to wavelength ratio t/λ is 0.2, R can reach -12dB; When t/λ=1, R is -30dB; When t/λ=8, R is -50dB.

Has flame retardant properties: meets the requirements of the US Navy Laboratory Report NRL8093 (1977) Test I Voltage Endurance, Test II Flame Ignition and Propagation Difficulty, and Test III Flame Retardant Test. Its oxygen index can meet general fire protection requirements and can pass fire simulation tests, and its flame retardant effect is long-lasting. Power capacity of 0.8KW/m2, short-term 1.0KW/m2.

★ Oxygen index - ≥ 28%, tested in accordance with GB/T2406-93 "Plastic Combustion Performance Test Method - Oxygen Index Method" standard;

★ Combustibility - B2 level combustible material, tested in accordance with the GB8624-1997 "Classification Method for Combustion Performance of Building Materials" standard.

Good flexibility: The conical shape is neat, beautiful and clean, and flexible and bendable. The operating temperature ranges from -50 ℃ to 90 ℃, and short-term temperature ranges from -100 ℃ to 120 ℃.

Environmental performance: All raw materials meet environmental requirements, and the main chemical components are non-toxic. At the same time, advanced inorganic flame retardants are used, which are non-volatile, odorless, and non-toxic. The flame retardant performance is stable and does not decrease after long-term use. Sponge material is very soft and easy to cut. It can be installed using adhesive or nylon hooks. When using adhesive, use a brush to evenly apply it to both sides that need to be glued. The newly built darkroom should strengthen ventilation in the first 1-2 years.

It is a challenging problem for EMC anechoic chambers to meet the site requirements for radiation interference testing at low frequencies (i.e. 30MHz to 300MHz), with the most critical issue being the performance of absorbing materials in the low frequency range.

There are two common types in the marketMagnetic absorberThin sheet and square ferrite tiles. Its main component is NiZn ferrite, which is processed through ceramic technology to obtain high magnetic permeability and high magnetic loss tangent to ensure its excellent absorbing performance. By proper design, magnetic absorbers with a thickness of only a few millimeters have good absorption ability for normal incident waves at the low frequency end of 30MHz.

Installation method:

Combining pasting and screw fixation methods. The installation gap between ferrite tiles has a significant impact on the absorption performance, and it is required that the gap should not exceed 1mm.

In order to solve the problem of poor high-frequency performance of ferrite tiles, a conical absorbing material composite absorbing material was matched on the ferrite tiles to achieve broadband absorption of electric waves.