Design, Fabrication, and Testing of a Modular Magnetic Field Microsensor on a Flexible Polymer Foil
In contrast to existing microelectromechanical systems (MEMS), this paper describes the development, fabrication, and testing of an anisotropic magnetoresistance (AMR) microsensor using a 7 μm thick polymer foil as substrate material. The modular magnetic field micro sensors are fabricated on a standard 4 in Si Wafer due to handling purposes during the sensor fabrication process. To enable a release of the micro sensors at the end of the fabrication process, initial investigations concentrated on the proof of principle applying a deep reactive-ion etching (DRIE) process to structure the Si wafer. The DRIE process was used to structure Si frames, which serve as carriers for the modular magnetic field micro sensors. For the evaluation of the fabricated modular magnetic field micro sensors, electrical resistance measurements were accomplished. The aim of these investigations was the characterization of the magnetic field dependence of the electrical resistance. The electrical output signal of the AMR sensors were subsequently compared to electrical resistance measurements of AMR sensors fabricated on a Si substrate and served as reference. The measurement results show a marginal effect of the substrate material on the characteristics of the AMR sensors.
Design and Fabrication of a Modular Eddy Current Micro Sensor
In order to provide a contactless measurement technique for the detection of surface damages, a modular design of an eddy current micro sensor was developed and fabricated in thin- fllm technology. The sensor is intended to be applied for the detection of cracks in ferrous and non- ferrous metals. The sensor consists of two parts, a single-turn excitation coil and an anisotropic magneto-resistance (AMR) sensor. The AMR sensor detects the change of the magnetic fleld induced in the sample by the excitation coil. The sensor is capable of detecting defects which are smaller than 50"m.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.