In this blog, we will go over everything you need to know about thermal barrier coatings. From the advanced materials used, the temperature protection they offer, and the application methods. Thermal barrier coatings are highly customisable and require expert guidance to achieve optimal results. Read on to find out how Alphatek can help you find the best coating solution for your engineering needs.
Advanced Materials
The first thing you need to know about thermal barrier coatings is the advanced materials we use to achieve first-rate results.
Thermal barrier coatings harness the insulation properties of superalloy metals and ceramics. By spraying these materials onto a substrate, it alters the surface quality and thermal performance.
Materials used in thermal barrier coatings allow components that would otherwise fail in extreme environments to operate for a prolonged lifespan.
Ceramics
Ceramics, such as yttria-stabilized zirconia (YSZ), are often used in thermal barrier coatings. Properties of ceramic coatings:
- Excellent Thermal Resistance: Ceramics offer highly effective thermal insulation properties. For applications that require isolated thermal energy, ceramic coatings offer a solution.
- Low Thermal Conductivity: Ceramic coatings are suitable for applications that require isolated thermal energy. The low conductivity minimises the transfer of heat to unwanted areas.
- Stability: It is important that thermal barrier coatings maintain their insulation capabilities over prolonged periods, which ceramic coatings like YSZ will. This enhanced durability prolongs the lifespan of both components and the coating itself.
Metallics
Metallic coatings are another common material used for thermal barrier coatings. Properties of metallic coatings:
- Oxidation Resistance: A sprayed alloy forms a stable oxide layer, which then works effectively to protect the underlying substrate from the impact of oxidation and corrosion.
- Strong Adhesion: Metallic coatings are renowned for their impressive adhesion, leading to stronger, more durable coatings.
- Thermal Shock Resistance: Metallic coatings offer thermal shock resistance, protecting components that are required to endure extreme temperature changes.
Composite
Composite coatings are a combination of ceramic and metallic coatings. Properties of composite coatings:
- Tailored Thermal Conductivity: Combining the thermal performances of both metallic and ceramic coatings adjusts the overall composition. Therefore, the conductivity can be tailored for specific applications.
- Enhanced Durability: Composite coatings merge the properties of both ceramic and metallic coatings, resulting in a tougher coating.
- Customisable: The measurements/ratios of composite coatings are highly customisable. Properties from different coating materials can be drawn out, leading to enhanced thermal protection, mechanical strength, and oxidation resistance.
Extreme Temperature Protection
In a lot of mechanical engineering applications, extreme temperatures are either required or generated due to vigorous activities or friction.
Thermal barrier coatings are particularly useful for applications that require isolated thermal energy. By reducing heat transfer, extreme temperatures do not spread to unwanted areas or damage the underlying substrate.
To ensure the best results, thermal barrier coatings usually have a multilayer structure. This ensures complete protection from thermal cycling, extreme heat, oxidation, and corrosion.
Thermal barrier coatings are also designed to mitigate thermal stress. When a component reaches extreme temperatures, it may cause expansion or contraction. The coating accommodates this by expanding, which prevents cracks from forming or delamination. This ensures that the underlying substrate is always protected, and the coating performance is not compromised.
Application Techniques
Now you know about the materials used, and the quality of thermal protection they offer, the final thing you need to know about thermal barrier coatings is the application techniques.
There are various application methods for thermal barrier coatings. Thermal spraying is highly customisable, based on the application requirements. Some components must adhere to specific requirements and the materials used for spraying or the substrate itself are interchanging too.
Application techniques for thermal barrier coatings are constantly being innovated. The more traditional methods are also highly effective. Ultimately, the application method alters the final result.
Before application, a spraying engineer will consult with their client to determine their needs, in terms of thermal insulation, protection, conduction etc. This will impact the materials and application techniques the spraying engineer uses, to achieve optimal results.
For more technical insight into spraying methods, check out our blog The Science Behind Metal Spraying.
Benefits Of Plasma Spraying
- Versatile Application: It can be used on various substrate materials. The precision of plasma spraying means it can be used on intricate components.
- Thickness Control: Plasma spraying can be applied in layers, meaning the thickness can be controlled. The geometries of components are unaltered by thinner applications, yet they are protected from thermal fatigue.
- Strong Adhesion: The rapid cooling on the substrate forms a strong adhesion, enhancing the durability of both the component and the coating performance.
Benefits Of High-Velocity Oxygen Fuel (HVOF)
- Dense Overlay: The result of HVOF coatings is a dense overlay, with low porosity. HVOF coatings are therefore excellent for providing corrosion and wear resistance.
- Strong Adhesion: The high-velocity spray method provides excellent adhesion, which prolongs the lifespan of the coating.
- High Deposition Rates: The method of HVOF spraying is highly efficient and the application time is short.
Thermal Barrier Coatings From Alphatek
Now you’re up to date on everything you need to know about thermal barrier coatings.
At Alphatek, we extend our independent services to a range of industries, providing metal spraying, thermal spray coatings, fluoropolymer coatings and finishing solutions.
Our thermal barrier coatings work effectively to confine heat in applications where it is required and isolate it from areas where it is unwelcome. We have an extensive range of thermal barrier coatings, suitable for a range of applications, which help achieve an otherwise unattainable level of performance.
If you’d like more information on thermal barrier coatings, you can read our recent blog post, Find A Thermal Barrier Coating Solution For Your Specific Needs.
For any queries or detailed product descriptions, please contact us by calling +44 (0) 1706 821021 or emailing us at postbox@alphatek.co.uk
