Novel force sensor based on hard diamond-like carbon films
This paper deals with the development of novel multifunctional carbon based sensor layers for use as force and pressure sensors in various mechanical applications. The diamond-like coatings (DLC) have been optimized for an effective variation of the electrical resistivity in dependence of the applied mechanical forces. The structure of those layers was amorphous for undoped and nano-crystalline for metal doped coatings. It was found, that the force sensor worked effective by the introduction of normal forces. The multifunctional diamond-like-carbon based coating showed besides the force sensitivity of the electrical conductivity excellent tribologic properties. Because of the extreme hardness and high elasticity in the order of 15 - 30 GPa and 140 - 270 GPa, respectively, the coatings can be applied directly to mechanical parts. The fabrication was done by means of sputtering and plasma CVD techniques. The friction against steel was as low as 0.1. It turned out, that the novel sensor layer can be used in various technical applications. Examples of characterization and applications will be discussed.