Piezo resistive thin film sensor system

This paper presents the latest investigations of thin film sensor developments based on amorphous hydrogenated carbon films. The piezo resistive layer is deposited in a plasma enhanced chemical vapour deposition process in a thickness of 4-6 mum. The advantage of this film is a excellent tribological behaviour with a hardness of 20-40 GPa and a coefficient of friction of 0,2 as it is well known from the diamond like carbon layers [1,2,3] combined with a piezo resistive characteristic [4]. This layer can detect loads without the need of elongation. A special sensor system in the shape of a washer can be easily integrated in screw joints to detect the normal load distribution.