what are different types of corrosion sensors?

what are different types of corrosion sensors?

what are various kinds of sensors which can sense/measure corrosion rates etc..? in materials

In general, corrosion sensors can be use for (but are not limited to)
-Monitor for localized corrosion in process and cooling water systems
-Coating and paint integrity and performance
-Internal corrosion of natural gas pipelines
-Stress corrosion cracking

As such, there are several different types of corrosion sensors. Again, there are likely far more than those I am about to list, but at least these will give you an idea their application and uses:
-Multielectrode Array Sensor (MAS) Probe
-Localized Corrosion Monitoring
-Coating and Paint Integrity Monitoring
-Natural Gas Pipeline Internal Corrosion Monitoring
-Stress Corrosion Cracking Monitoring

The following processes are also used to monitor corrosion, but are not used in real-time:
-linear polarization resistance
-electrochemical noise
-electrical resistance methods

Follow the link below for more detailed information.

the most used type of corrosion sensors or device used to monitor corrosion are:
– Corrosion coupon, piece of metal exposed to the environment and then extracted and the loss of weght is measured to calculate the corrosion rate
– UT thickenss mat, small sensor attached to the external surfaces of an equipment. tehy read the thickness of the metal and calculate the corrosion rate
– LPR linear polarization resistance probe, they measure the polarization of an electrode and extrapolate the corrosion rate
– Resistance probe, a small piece of metal is exposed to the fluid. this probe is connected to a electronic device that calculate the reduction of resistance of the probe due to corrosion and calculate the corrosion rate
then there are other more sophisticated like FSM, Long range UT..