- Corrosion Experts
- Technical Groups
It is essential for defence forces to have equipment and infrastructure that is functional and operationally ready. Corrosion poses a severe threat to the operational readiness of defence forces. Analyses have been conducted into the impact of corrosion in the Australian Defence Force (ADF).
Royal Australian Navy
The RAN operates in environments that are harsh and subject to corrosion. Knight et al.64 report on a corrosion cost analysis of corrosion on four frigates in the RAN. Three different costing methods were used (a direct analogy of USN frigate corrosion costs, a proportional analogy of USN frigate costs and a bottom-up method).
Method 1 (comparison to U.S. studies) gave an estimated corrosion cost between $81 million to $126 million Australian dollars (AUD); Method 2 (mixed costing approach) gave much lower estimates of $41 million to $72 million AUD; and Method 3 (detailed costing using RAN maintenance records) showed an estimated cost of ~$94 million AUD. The costs were then extrapolated across the RAN fleet. Using corrosion costs relative to total maintenance costs from the USN, and MSA costs for the RAN, the cost of corrosion for the entire RAN fleet during the 2015 calendar year was estimated to be between $A137 to $A242 million.
Costs of corrosion in the RAN can be reduced through implementation of effective technologies. The Australian Defence Magazine reported in 2018 that the RAN was investing in Envelop protective covers for use initially on HMAS Canberra and Adelaide. These Envelop covers have been shown in the USN to save $US30,020 of corrosion maintenance cost within the first two years of use. The USN has made the use of these covers mandatory on all vessels.
Royal Australian Air Force
RAAF aircraft are operated beyond their original design life. As a result, more corrosion is likely to develop in airframes as protective coatings deteriorate. The costs of dealing with corrosion are likely to increase. The use of Structural health monitoring (SHM) systems that provide diagnostic and prognostic information on corrosion-related damage will enable maintainers and operators of aircraft to manage the prevention and control of corrosion in aircraft structural components on a condition basis rather than on elapsed number of (flying) hours.
In defence, older airframes are reporting that corrosion can be the primary cause of structural nonconformances, and that non-availability due to inspection and correction can be upwards of 10%. The cost of corrosion for the period from January 2010 through to December 2011 was assessed as $2.49 million. For new airframes, improved components incorporating carbon composites are causing significant issues due to galvanic corrosion around metallic fasteners, and original equipment manufacturers are mandating extensive inspection regimes where 70 to 75% of maintenance actions are for corrosion control.
The Defence Science and Technology Organisation (DSTO) has been developing tools to monitor the atmospheric corrosion of military aircraft. Initially, this work involved the development and use of sensors, both corrosion and environmental. The work has evolved to include corrosion models and prognostic capabilities to give a more complete corrosion prognostic health management (CPHM) system. The anticipated outcome is to facilitate condition-based maintenance for corrosion prevention, which will replace maintenance dictated by either flying hours or service duration.
Corrosion is also an issue with helicopters. A joint development program between DSTO and researchers at Monash and Swinburne Universities has developed a silane coating. This coating is completely biodegradable and non-toxic so people can handle it safely. It also delivers the maximum corrosion resistance ever achieved for magnesium alloys. It could be used to repair the corroded gearbox housings of SeaHawk helicopters.