The low-temperature deposition of BaNi_(2-x)Co_xFe₁₆O₂₇ thin films with a Ba hexaferrite structure for electromagnetic shielding was studied. The BaNi_(2-x)Co_xFe₁₆O₂₇ thin films produced through the spin spray process were suitable for thin film deposition on a flexible substrate because it crystallized well at low temperature below 90℃. The change in shielding characteristics depending on the Co content of the BaNi_(2-x)Co_xFe₁₆O₂₇ thin film was investigated, and excellent shielding characteristics with S21 of -1 dB were obtained in a wide frequency range of 26~40 GHz when the Co content was 0.4 or more. The purpose of this study is to analyze changes in shielding properties caused by change in Co content in relation to phase changes in BaNi_(2-x)Co_xFe₁₆O₂₇ and obtain basic data for developing excellent flexible electromagnetic wave shielding materials.

Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as a resistive gas sensors for the H2 gas detection. Sensor films were fabricated by the air spray method using the multi-walled CNTs dispersion solution on the glass substrates cured with plasma and nitrocellulose. Sensors were characterized by the resistance measurements in the self-fabricated oven in order to find the optimum detection properties for the hydrogen gas molecular. The sensitivity and the linearity of the MWVNT sensors using the glass substrate cured with plasma for the H2 gas concentration of 0.06∼0.6 ppm are 0.013∼0.097%/sec and 0.131∼0.959%FS, respectively. The MWCNT film was excellent in the response for the hydrogen gas moleculars and its reaction speed was very fast, which could be using as hydrogen gas sensor. The resistance of the fabricated sensors decreases when the sensors are exposed to H2 gas.