Nano-magnetic sensors applied to non-destructive evaluation – CANOE

Industries undergo today a strong pressure to reinforce the reliability and the safety of the products, while improving their productivity. To take up this challenge, they use non destructive testings (NDT) methods which gather processes ready to provide information on the health of a part without deteriorting it. Among the existing techniques, eddy currents method (EC) occupies a major place by ensuring the detection of the subjacent or surface breaking flaws.

The EC method knows today a deep change to fulfill an increase in the performances of inspections required by the industries. The stake lies in the detection of very small flaws (<100µm) and burried flaws (under several mm), while decreasing time inspection to improve the rentability. To answer these constraints, new technologies of magnetic sensors are investigated. These technologies, resulting from collective manufacturing, present a high sensitivity and a good resolution, and offer interesting prospects in terms of phase-array realization. The IMAGINE project , labellized in 2005 in the call PNANO, showed the feasibility of the adaptation of magneto-resistance and magneto-impedance nano-components to the non destructive testing. However, an important work remains to be undertaken to make evolve these promising technologies from laboratory use to industrial exploitation.

CANOE aims at proposing technical development making reliable the manufacture of phase array EC probes containing magnetic nano-components. This project will lead to the realisation of demonstrators integrating giant magneto-resistances (GMR) and magneto-impedances (MI). In the field of the GMR, technological developments will be implemented to improve the sensitivity of the sensors. Concerning the nano-component the replacement of the IrMn barrier by the use of antiferromagnetic insulating (NiO) will reduce the effects of shunt, the improvement of the packaging of the probe will reduce the lift-off. An exploratory work will in addition be done to transpose GMR technology on flexible substrate. In the field of the magneto-impedances, the scientific devlopments will make possible to realisation of phase array probe containing MI nano-components. Innovating developments will be implemented such as the design of a phase arra architecture, the realisation of micro-winding around the nano-component.

CANOE will federate during forty-two months eight partners: CEA LIST will ensure the coordination of the project, the design, integration and the evaluation of the EC probes, THALES and the UMR 137 will carry out the phase array sensors containing GMR, the LGEP and the IEF will ensure the development of phase array sensors containing MI, AREVA and EADS IW will bring the application context to the project and the SME STATICE will take part in the integration of the EC probes, and will ensure the industrial transfer of developed technologies.
CANOE will propose more sensitive and phase array EC probe, and thus more powerful for the NDT market. Smaller flaws and/or located in difficult zones for inspection could be detected (turbine blades, tubes, weldings, riveted structure).