P. Corrigan

Interaction of Ce(dbp)3 with surface of aluminium alloy 2024-T3 using macroscopic models of intermetallic phases

Abstract The mechanism of corrosion inhibition by cerium(III) dibutylphosphate [Ce(dbp)3] on aluminium alloy 2024-T3 (AA2024-T3) has been investigated using macroscopic models of the intermetallic (IM) phases in the alloy. Polished specimens of pure Al (99·999%) and the macroscopic IM phases Al2CuMg, Al7Cu2Fe and Al3Fe were each coupled to a large surface area of AA2024-T3 to simulate the interaction they experience in the alloy. Samples were immersed in 0·1M NaCl with 200 ppm Ce(dbp)3 for 24 h, and the resulting surfaces characterised by scanning electron microscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy and Raman spectroscopy. Ce(dbp)3 was found to interact differently with each of the different phases examined, providing evidence for a multifunctional corrosion inhibition mechanism.

Extrusion Processing of Starch Film

Processing behaviors of starch film using a twin screw extruder were studied; in particular the effect of processing conditions, such as temperature, screw speed, feeding speed, and water content, on the extrusion torque and die pressure were systematically investigated. A specific focus of this work was to investigate the effect of amylose/amylopectin ratio containing in cornstarch on the film processing and performances. It was found that the processibility was decreased as the amylose content increased. Pre-mixing and equilibration improve the processibility of starch films, especially for the high amylose starches. The high amylose starches need higher moisture content and temperature for film extrusion.

Aqueous Corrosion Testing and Neural Network Modeling to Simulate Corrosion of Supercritical CO2 Pipelines in the Carbon Capture and Storage Cycle

A database was constructed from tests in aqueous electrolytes simulating the damage that may occur to ferrous transport pipelines in the carbon capture and storage (CCS) process. Temperature and concentrations of carbonic acid (H2CO3), sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3), sodium nitrate (NaNO3), sodium sulfate (Na2SO4), and sodium chloride (NaCl) were varied; the potentiodynamic polarization response, along with physical damage from exposure, was measured. Sensitivity analysis was conducted via generation of fuzzy curves, and a neural network model also was developed. A correlation between corrosion current (icorr) and exposure tests (measured in the form of weight and thickness loss) was observed; however, the key outcome of the work is the presentation of a model that captures corrosion rate as a function of environments relevant to (CCS) pipeline, revealing the extent of the threat and the variables of interest.

Use of Aqueous Solutions to Simulate Supercritical CO2 Corrosion

Capturing and storage of anthropogenic carbon dioxide (CO2) requires the transport of CO2 with varying combinations of impurities depending on the capture technology and source. Traditional pipelin...

Development of a sensor-based learning approach to prognostics in intelligent vehicle health monitoring

This paper reports the development and testing of an intelligent sensing network for monitoring corrosion of aircraft structures. The agent-based system uses sensed microclimate and corrosion data with an innovative analysis approach to diagnose corrosion and to infer the presence of corrosion in locations such as crevices and fasteners where it cannot be sensed directly. An important feature of the system is its ability to provide prognostic information to enable timely corrective maintenance scheduling.

Application of Atomic Force Microscopy on Studying Micro- and Nano-Structures of Starch

This paper reviews the application of atomic force microscopy (AFM) to the study of starch structures, including both macrostructure of starch granules and the nanostructure of molecular chains. It introduces the different techniques of sample preparation and discusses what AFM could observe. The paper summarises the present situation of the application of AFM in the study of starch structures and guides the direction for further research.

Distributed quantum dot sensors for monitoring the integrity of protective aerospace coatings

The development of a non-destructive health-monitoring system for painted metal structures is being pursued. The system is based on sensing the fluorescence emission intensity of quantum dot particles that have been distributed throughout protective aerospace coatings. The quantum dots serve as distributed sensors that can provide localized information on the corrosive conditions that exist within the paint film. Consequently this provides an early indication of several key aspects, which include: the quality of film application; the in-service loss of corrosion inhibitor; and the mechanisms of failure. In this paper we present the successful distribution of CdSe/ZnS core-shell nanoparticles into a commercial chromate-inhibited aerospace primer and demonstrate a correlation between available levels of hexavalent chromium corrosion inhibitor and quantum dot photoluminescence during accelerated corrosion testing. The development of a non-destructive inspection device utilizing a microchannel gated intensifying camera is in progress. Finally, we discuss the limitations of available quantum dot materials and provide a vision for non-destructive corrosion inspection in metal structures.

Frequency and duration of wetness periods on surfaces in airframes

Abstract This study reports on the wetting of sensors positioned in two diverse positions in two different air frames. The two spaces studied were a subgalley space in a commercially operated 747 and the cargo bay area of a military operated 707. The study found that in the 707 cargo, bay wetness events were relatively uncommon, with the majority of events lasting from 30 to 90 min but with some events lasting up to 600 h. In the 747 subgallery, wetness events were common, with the most frequent wetness period being 30 min (although periods of up to 270 min were observed) and the average wetness event being 50 min. The implication of such wetting intervals to the wetting and chloride ingress into intact paint films and the release of chromate into defects in paint films are discussed.

Recent Progress in Intelligent Vehicle Health Monitoring

Boeing, CSIRO and DSTO are collaborating on research into Intelligent Health Monitoring for Aerospace Vehicles (IHMAV). The system has the ability both to predict the probable development of corrosion and to elucidate the environmental factors that are promoting corrosion. The paper discusses the system capabilities, data output including the data derived from previous monitoring programs on B-707. In particular this data established the connection between local microclimate and corrosion events and highlights variations in microclimate and corrosion that can occur for different spaces in an airframe and different airframes.

DEVELOPMENT OF A CORROSION SENSOR FOR AN AIRCRAFT VEHICLE HEALTH MONITORING SYSTEM

A Rayleigh‐wave‐based sensor has been developed to measure corrosion damage in aircraft. This sensor forms an important part of a corrosion monitoring system being developed for a major aircraft manufacturer. This system measures the corrosion rate at the location of its sensors, and through a model predicts the corrosion rates in nearby places on an aircraft into which no sensors can be placed. In order to calibrate this model, which yields corrosion rates rather than the accumulated effect, an absolute measure of the damage is required. In this paper the development of a surface wave sensor capable of measuring accumulated damage will be described in detail. This sensor allows the system to measure material loss due to corrosion regardless of the possible loss of historical corrosion rate data, and can provide, at any stage, a benchmark for the predictive model that would allow a good estimate of the accumulated corrosion damage in similar locations on an aircraft. This system may obviate the need for c...