Environment Spectra and Corrosivity Monitoring Using Electrochemical and Electrical Resistance Sensors
This Aerospace Informational Report (AIR) provides guidance on using environmental, electrochemical, and electrical resistance measurements to monitor environment spectra and corrosivity of service environments, focusing on parameters of interest, existing measurement platforms, deployment requirements, and data processing techniques. The sensors and monitoring systems provide discrete time-based records of 1) environmental parameters such as temperature, humidity, and contaminants; 2) measures of alloy corrosion in the sensor; and 3) protective coating performance in the sensor. These systems provide measurements of environmental parameters, sensor material corrosion rate, and sensor coating condition for use in assessing the risk of atmospheric corrosion of the structure. Time-based records of environment spectra and corrosivity can help determine the likelihood of corrosion to assess the risk of corrosion damage of the host structure for managed assets, aiding in establishing maintenance intervals and processes.
Diagnostics for determining damage to a structure and prognostics for predicting the remaining useful life before reaching a critical damage threshold of corrosion are not within the scope of this document. Also, not within the scope of this document are other nondestructive evaluation (NDE) tools or structural health monitoring (SHM) technologies that can directly assess corrosion-based damage. While this document is focused on air-vehicle environments, many of these topics would translate to other industries and systems without much modification.
Rationale: The purpose of this document is to describe available environmental electrochemical, and electrical resistance sensor technologies and techniques for on-board air-vehicle environmental spectra and corrosivity monitoring, along with outlining data processing and handling methods. This document provides a system-level approach, covering sensor selection, data management, data reporting, and deployment.