Thermal spray coatings or metal coatings are used across a wide range of industries to enhance, protect and restore metal parts and surfaces to improve both their functionality and appearance.
Today we’re exploring the topic of thermal spray coatings and the aerospace industry, and taking a closer look at the types of coatings used and how the application of thermal spray coatings improves performance and safety.
Why Are Thermal Spray Coatings So Important to the Aerospace Industry?
Metals are the most commonly used material in aviation and aerospace due to their excellent weight-to-strength ratio, durability and resistance to high temperatures, including UV rays from the sun.
However, without thermal spray coatings, these metals wouldn’t be able to withstand the extreme conditions that aircraft and spacecraft are routinely subject to.
Metal coatings imbue specialist properties to metal surfaces to enhance performance, and also to ensure that aircraft parts and structures are able to meet rigorous safety standards. Examples of this include coatings that offer oxidation resistance or a thermal barrier, as well as abradable coatings, commonly used in aircraft jet engines.
Metal spray coatings also improve the longevity and hardiness of an aircraft, resulting in less wear and tear, which reduces the likelihood of parts failure or the need for costly repairs or replacement parts.
Thermal spray coatings, therefore, are a vital aspect of aerospace design, engineering and manufacture.
Applications for Thermal Spray Coatings in the Aerospace Industry
Thermal spray technology has a number of applications within aerospace. Here are some of the most common parts of aircraft on which thermal spray coatings are used.
- Landing gear (including bearings and axles)
- Wing structures
- Transmission systems (such as gears and shafts)
- Engines (including combustion liners and transitions, discharge nozzles, compressor blades, turbine blades and engine cowling)
- Actuation systems (pistons and pumps)
- Valves
- Airfoils
Types of Coatings Used in the Aerospace Industry
The most common thermal spray coatings utilised in the aerospace industry include:
- Tungsten carbide
- Chromium carbide
- Nickel graphite
- Aluminium bronze
- Zirconium oxide
Thermal Spray Coating Techniques for Aerospace Applications
There are a variety of methods that can be used when undertaking thermal spray coating for aerospace applications. Frequently employed techniques include HVOF, plasma spraying and flame spraying.
HVOF for Aerospace
One of the most commonly used techniques to apply thermal spray coatings in the aerospace sector is HVOF (High-Velocity Oxygen Fuel spraying).
This involves using a fuel gas and oxygen torch to propel molten powder onto a surface at high velocity. The powder then sets and solidifies into the desired coating.
HVOF offers exceptionally high bond strength and can be used for numerous applications, including applying coatings that combat wear and tear (such as anti-abrasion or erosion coatings) or protective coatings against corrosive conditions, as well as to coat parts that are subject to high temperatures.
Plasma Spraying for Aerospace
In plasma spraying, the material particles are partially melted down before being accelerated through a plasma jet to deposit the coating across the surface of the specific part being treated.
Plasma spraying allows for full customisation to meet the specific needs of that part, whether that’s thermal and electrical insulation or corrosion resistance.
Flame Spraying for Aerospace
Another technique commonly used to apply thermal spray coatings in the aerospace industry is flame spraying.
Similar to HVOF, flame spraying combines fuel with oxygen and can be used to apply a range of thermal spray coatings. However, it is a comparatively low-energy method of application, meaning it can be used on parts that have low thermal stability.
Flame spraying can be used to repair and restore aerospace components and to apply abradable and clearance control coatings.
Thermal Spray Coating Services by Alphatek
We hope this has helped to explain the vital partnership between thermal spray coatings and the aerospace industry.
With over a century of cumulative coating expertise, Alphatek provides expert metal coating services to enhance and restore surfaces across multiple industries, including aerospace.
To find out more about our thermal spray coating services, don’t hesitate to get in touch. Alternatively, you can call us on 01706 821021 or email postbox@alphatek.co.uk.
If you’d prefer to visit Alphatek in person, you’ll find us 20 miles north of Manchester. Be sure to check our opening times when planning your visit.
