120M999

Summary:

There are different ways of hiding from radar signals, today the most intensively studied area is radar absorbing materials (RAM). Considering strategic importance of prevention of electromagnetic waves in the defense and communication sector, studies in this area have taken our country to a higher level in both national and international platforms. On the other hand, in parallel with new industrial developments, technical knowledge in this field has started to increase in our country. In terms of researcher potential and physical infrastructure, Hacettepe University is well suited for research done and to be conducted in this field.

Today, solutions developed for decreasing radar cross-section can be easily applied to the air and sea vehicles since all personnel and equipment can be hidden in their body. However, the body shapes of tactical vehicles and fire support elements used by ground units, environment in which they are used, and the equipment that used by the personnel outside the vehicle left them unprotected agains to radar-guided ammunition.

Covers will be light and easy to use as they consist of f-group element doped barium-ferrite and strontium-ferrite-based nanoparticles with high absorption coefficient. Although it is known in the literature that adding F-group elements increases absorption properties, the effect of additions to barium and strontium ferrite structures has not been studied in literature. It is one of the original values ​​of this study. In preliminary experiments, barium ferrite nanostructures with a particle size ranging from 60 to 10 nm were observed to provide a reflection loss of -30 dB in the range of 8-14 GHz. In addition, Nd addition has been observed to increase coercive field of ​​barium ferrite nanostructures. This result supports prediction that f-group doping will increase absorption coefficient. However, as is known, the distribution of magnetic structures in a matrix changes the distance between particles and thus magnetic and absorption properties. Fact that magnetic and absorption properties of structures to be obtained by adding the RAMs produced within scope of this project to polyethylene at different rates have not been studied in the literature also makes study technologically and scientifically unique.

Nanostructures based on barium and strontium ferrite will be prepared by mechanical grinding method. High particle size distribution, which seems to be disadvantage of this method, will be used as an advantage in the study and RAMs showing resonance absorption in a wide frequency range will be prepared.

The prepared RAM will be distributed into polyethylene with ultrasonic-probe and nano-composite covers of different thicknesses will be produced in coupon size (25x25 cm) with hot rollers. XRD and RAMAN will be used for structural analysis of samples at each stage of study. Magnetic Properties will be determined by VSM. The mechanical strength will be determined by tensile tests both after production and after UV aging. Radar cross-section reduction coefficients of covers will be determined by performing open field reflection / passing tests in the range of 8 - 18 GHz.

With this project, TRL4level coupon product will be obtained. Thus, basic research will be completed in the production of RAM covers required by our land forces on field, and experienced researchers will be trained on the subject. This will open the way for both production of a need of the defense industry with domestic and national facilities, and to contribute to the national economy as an export item.

In addition, the project will be carried out as multi-disciplinary with participation of Physics Engineering, Electric and Electronic Engineering and Chemistry departments under direction of Nanotechnology Department, so that interdisciplinary relations will be developed and graduate students with multi-disciplinary working experience will be trained.