An optical fibre corrosion sensor with an electroless deposit of Ni-P

The feasibility of an optical fibre corrosion sensor (OFCS) is studied. A P CS fibre is metallised with chemical nickel-phosphorus deposit on an unclad ded part of 2 cm length. The light power (P) transmitted through the fibre is registered as a function of the angle of incidence (CL) Of the light emi tted by a laser diode at 670 nm wavelength. The P(a) curves are modified wh en the nickel coating is corroded in phosphoric acid solutions, the full wi dth of these curves at half-maximum increases when the density of corrosion pits increases. Kinetic curves of the corrosion are determined in differen t concentrations of phosphoric acid. This type of corrosion sensor can be i nserted in structures in order to follow in situ the corrosion state of the structure. (C) 2001 Elsevier Science B.V. All rights reserved.