Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

Abstract

Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

Structural and Morphological Characteristics of Polyaniline Synthesized in Pilot Scale

“…Despite using appropriate materials and process for protection, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures (Rinaldi et al 2012). There are several new technologies now under consideration for aluminum alloys protection including conductive polymers as primers without Cr-based metal pre-treatments (Bierwagen 2001).…”

A Review of Corrosion in Aircraft Structures and Graphene-Based Sensors for Advanced Corrosion Monitoring

“…performs processing operations [105]. The concept of multi-parameter integrated sen was investigated by Rinaldi et al, where a distributed corrosion sensing network proposed to detect hydrogen, relative humidity and temperature variations [54]. The tem includes polyaniline/carbon nanotubes-based sensors for hydrogen gas and humi detection [54].…”

“…C bining carbon nanotubes (CNTs) with PANI enhances the conductivity of the semi ductor by improving the charge carrier mechanism in PANI [54]. In this configura PANI/CNTs composite material was deposited on simple sensing chip made of interd tated electrodes as shown in Figure 13 [54]. The sensor exhibits excellent sensitivity to humidity compared to commercially a able sensors [54].…”

“…In this configura PANI/CNTs composite material was deposited on simple sensing chip made of interd tated electrodes as shown in Figure 13 [54]. The sensor exhibits excellent sensitivity to humidity compared to commercially a able sensors [54]. However, its response to variation in hydrogen concentration was ited by hydrogen bonding sites in the PANI/CNTs material or the presence of resi moisture as a result of the fabrication process [54].…”

“…Sensor nodes is a monolithic integration approach that incorporate sensors targe different analytes in the same node. It is a novel approach that can be useful in air corrosion monitoring, where several sensors targeting the corrosion factors outline Figure 2, are encapsulated in the same node and placed in critical locations of the air The sensor exhibits excellent sensitivity to humidity compared to commercially available sensors [54]. However, its response to variation in hydrogen concentration was limited by hydrogen bonding sites in the PANI/CNTs material or the presence of residual moisture as a result of the fabrication process [54].…”