Direct fabrication of thermosensors by laser micro-cladding functional materials

Abstract

Sensors are very important products for the information society. As one of the most important sensors, thick film thermo sensors are developing towards to smaller sizes, higher integration and higher precision. Comparing with the thick film thermosensors fabricated by silk screen printing, the laser micro-cladding technique is more flexible for its direct fabrication without mask in advance. Furthermore, the sensors fabricated by this technique may be more precise with better quality. In this presentation, thick film thermosensors are fabricated on 96%wt Al2O3 ceramic substrate successfully by laser micro-cladding electronic paste. The maximum scanning velocity to fabricate the coatings with good quality can reach 70mm/s. The sensors have excellent surface morphologies and narrow widths (minimum 60µm) with TCR 2330 ppm/°C, the answering time 2.3s and linearity tolerance <1°C. Besides, the fabricated thermosensors have excellent properties and stability after heat shock. The performances about the sensors fabricated by the laser micro-cladding technique are characterized by different methods. The experimental results demonstrate that the performances of the thermosensors fabricated by laser micro-cladding are equal to or even better than those fabricated by the traditional silk screen printing methods.