Corrosion Testing

Corrosion damage can be detected through a variety of testing methods, such as Visual Inspection, Non-Destructive Testing, and laboratory analysis of samples.

Destructive Testing methods can be used to identify corrosion by examining the surface of the material for signs of rust or pitting. Additionally, the material can be cut open to inspect the extent of corrosion within.

To better understand the extent of corrosion damage, it is essential to determine the type of corrosion present. Some common types of corrosion include Intergranular Corrosion, Pitting Corrosion, and Crevice Corrosion. Each type of corrosion can be identified using specific detection methods.

By using the appropriate detection and prevention methods, the negative effects of corrosion can be minimised, and the lifespan of materials can be extended.

Some early signs of corrosion include discoloration, pitting, roughness, and flaking of the surface. You may also notice a powdery residue or rust-coloured stains on the affected area. It’s important to address these signs promptly to prevent further damage.

These early signs of corrosion damage can include:

• Discoloration or staining on metal surfaces
• Flaking or peeling of paint or coatings
• Formation of rust or white powdery substances on metal
• Pitting or small holes on metal surfaces
• Soft spots or weak areas on metal structures
• Cracks or splits in metal
• Loose or missing fasteners or connections
• Changes in the shape or structure of metal
• Leaks or drips from metal pipes or tanks
• Unusual noises or vibrations from metal equipment

Different materials are affected by corrosion damage in different ways.

• Rust and discolouration are common forms of corrosion in metals, which occurs when iron or steel reacts with oxygen and moisture in the air.
• Corrosion can weaken the structural integrity of lead-based objects, making them more prone to failure.
• Nickel metals can also experience corrosion damage, causing them to deteriorate over time and resulting in a loss of strength and durability.
• Aluminium and copper metals can also experience corrosion, but they develop a layer on their surface that can slow down the corrosion process.

Some metals are well known for their corrosion-resistant properties, such as stainless steel, aluminium, and cupronickel alloys.

Stainless steel contains elements of chromium which helps it to form a naturally occurring, thin oxide layer across the surface of the metal to aid against corrosion damage. This protective coating makes it an extremely useful material for manufacturing a wide range of products and is used across many industries including nuclear and energy, marine and maritime, transportation, and much more.

Aluminium also forms an oxide layer when it encounters oxygen. While aluminium is naturally resistant to corrosion, it can still be affected by certain chemicals or conditions, so it is important to choose the right type of aluminium depending on its intended environment and take appropriate precautions to maintain its integrity.

Cupronickels are known for their excellent corrosion resistance. Some of its other properties and characteristics are good ductility, excellent thermal conductivity, and high electrical conductivity. It is commonly used in marine applications due to its resistance to seawater corrosion and in electrical components due to its conductivity.

Brass is an alloy of copper and zinc, and its corrosion resistance depends on the amount of zinc present. Higher zinc content can improve its resistance to certain types of corrosion.

Bronze is another copper alloy that can be resistant to corrosion, particularly in marine environments. Its resistance comes from the formation of a protective patina on its surface.

Copper itself is known for its excellent electrical conductivity, but it can also be corrosion-resistant in certain applications. Like bronze, copper can develop a patina that helps protect it from further oxidation.

Each of these metals has unique properties that make them suitable for different applications where corrosion resistance is important.

Whilst every industry can be affected by corrosion damage, there are certain industries that can experience corrosion more often than others.

• Transportation, Automotive and Aerospace; corrosion can be caused by weather conditions such as heavy rains and increasing flooding risks. This can affect vehicles, trains and train tracks, road traffic systems and safety signs.
• Automotive and Aerospace; corrosion can occur on key components such as jet engines, gearboxes, braking systems which can affect the safety and quality of essential components.
• Marine and Maritime; corrosion is extremely likely due to constant exposure of salt water and harsh environments. Ships, oil rigs and offshore energy systems can all be affected by corrosion.
• Construction; corrosion can affect the durability, safety and structural integrity of bridges, buildings, and other types of infrastructure.
• Energy, Oil and Utilities; corrosion can cause damage to integral pipelines for gas, water and oil supplies which can have an adverse effect on the environment and economy.
• Manufacturing; corrosion of key components and parts, can lead to machine breakdowns or failure of crucial production lines, resulting in significant downtime of equipment and reduced productivity.

It is essential for industries to take a proactive approach to corrosion prevention and mitigation to minimize the risks and costs associated with this pervasive problem.

Choosing the right materials for manufacturing components and products, such a corrosion-resistant alloys and metals, is the first step towards preventing corrosion damage. Factors such as the materials’ exposure to its intended environment, temperature, humidity, and any harsh chemicals or conditions are some key considerations when choosing appropriate materials.

Once the right material has been chosen, protective barriers or coatings on the material should be considered to aid in the prevention of corrosion damage. Coatings such as powders or paints, plating, anodising, and galvanising are all useful methods to give additional protection to a finished product.

Product aftercare is crucial; proper maintenance, such as regular inspection and cleaning of products and components can help detect early signs of corrosion or damage. If the environmental conditions can be controlled (maintaining humidity, temperature, and ventilation levels) they can support the prevention of corrosion damage.

It is important to note that corrosion is not always preventable, but identifying early signs of damage and taking necessary measures means that it can be managed effectively and reduces the likelihood of failure.

The economic impacts of corrosion damage include lost productivity, increased maintenance costs, and reduced lifespan of a product or component.

In addition to the economic impacts, corrosion damage can also have far-reaching environmental consequences. Corrosion can cause leaks and spills, leading to soil and water pollution. This can harm wildlife and ecosystems, and can also affect human health if contaminated water or soil is consumed.