corrosion sensor apparatus are disclosed for detection of contamination affecting metal based components and devices . for example , an apparatus comprises : a set of corrosion sensor elements comprising a first corrosion sensor element and at least a second corrosion element , each corrosion sensor element being coupled between a source and a monitor , wherein a width of the first corrosion sensor element is different than a width of the second corrosion sensor element , wherein each corrosion sensor element is susceptible to corrosion caused by an operating environment of the corrosion sensor elements ; and a set of reference elements comprising a first reference sensor element and at least a second reference sensor element , each reference sensor element being coupled between the source and the monitor , wherein a width of the first reference sensor element is substantially equal to the width of the first corrosion sensor element and a width of the second reference sensor element is substantially equal to the width of the second corrosion sensor element , wherein each reference sensor element is not substantially susceptible to corrosion caused by the operating environment of the corrosion sensor elements .