What is Plasma Spraying?

Plasma spraying is a thermal spray coating process that applies protective and functional layers of materials to industrial components. This coating technology delivers precise, durable surface treatments for enhancing component performance and longevity across manufacturing, aerospace, industrial, and power generation applications.

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Defining Plasma Spray Coating

Plasma spray coating uses high-energy plasma to melt and apply specialized materials onto component surfaces. The process's high temperatures enable strong bonding and consistent coating quality while accommodating materials that traditional coating methods cannot handle. This capability makes plasma spray coating essential for applying advanced ceramics, metals, and composites in critical industrial applications where surface protection directly impacts operational performance.

The Plasma Spray Coating Process

Plasma spray coating begins when an electric arc forms a plasma jet between a cathode and anode. Primary gases (typically argon or nitrogen) and secondary gases (hydrogen or helium) are ionized to form the plasma plume. The coating material is injected into this high-temperature plasma jet, which melts and accelerates toward the substrate. The molten particles flatten and solidify rapidly upon impact, creating a layered coating structure.

Different Plasma Spray Coating Techniques

Atmospheric Plasma Spraying (APS)

APS is the most widely used plasma spray technique, performed in normal atmospheric conditions. This method offers excellent versatility and cost-effectiveness for many applications. The process allows for high deposition rates and can accommodate a wide range of coating materials, making it suitable for large-scale industrial production.

Vacuum Plasma Spraying (VPS) or Low-Pressure Plasma Spraying (LPPS)

VPS/LPPS operates in a controlled atmosphere chamber under reduced pressure. This technique produces superior coating quality with minimal oxidation and improved density. The vacuum environment enables better control over coating properties and is particularly valuable for reactive materials or applications requiring exceptional coating purity.

Plasma Spray Applications

Aerospace Components

Advanced plasma spray coatings protect turbine blades, combustion chambers, and other critical aerospace components from extreme temperatures and wear. These coatings significantly extend component life and improve engine efficiency.

Power Generation

Thermal barrier coatings applied through plasma spraying protect gas turbine components, enabling higher operating temperatures and improved efficiency. The process helps extend maintenance intervals and reduce downtime.

Automotive Industry

Plasma coatings improve wear resistance in engine components and provide thermal management solutions for electric vehicle batteries. These applications contribute to increased vehicle performance and durability.

Electronics Industry

Plasma spray ceramics are used in the electronics and semiconductor industry due to their superior dielectric properties, corrosion, and wear resistance. These coatings find applications in etching chamber components as well as insulated bearings. 

Advantages of Plasma Spray Coating

Superior Coating Properties

Plasma-sprayed coatings deliver exceptional bonding strength that ensures long-term durability in demanding applications. The high-energy plasma process creates coatings with superior density and hardness characteristics that significantly outperform conventional coating methods. These coatings exhibit excellent wear and corrosion resistance across various operating conditions, providing reliable protection in aggressive environments. The process allows precise control over coating thickness and composition, enabling engineers to tailor solutions for individual application requirements.

Process Versatility

The plasma spray coating process offers remarkable material selection and versatile application methods. Engineers can work with an extensive range of materials, from metals and ceramics to advanced composites, expanding possibilities for innovative coating solutions. The process accommodates variable coating thickness requirements, from thin films to substantial protective layers, while maintaining consistent quality. Complex geometries pose no challenge for plasma spraying, as the process can effectively coat intricate surfaces and hard-to-reach areas. Precisely controlling multiple process parameters ensures optimal coating properties for each application.

Economic Benefits

Components protected by plasma coatings typically experience significantly extended operational life, reducing the frequency and cost of replacements. Organizations see substantial reductions in maintenance costs through decreased downtime and fewer repair interventions. Improved operational efficiency translates directly to bottom-line benefits. Compared to the costs of component replacement or alternative coating methods, plasma spraying is a cost-effective solution that delivers long-term value through enhanced performance and durability. 

Potential Challenges of Plasma Spraying

While plasma spray coating offers significant advantages, successful implementation requires careful attention to possible challenges. Here are the primary considerations for using this thermal spraying technology:

• Process Control - Maintaining consistent coating quality requires precise control of multiple parameters, including plasma gas composition, power input, and powder feed rate. Small variations can affect coating properties.
• Equipment Complexity - Plasma spray systems' sophisticated nature requires specialized expertise for operation and maintenance. Regular calibration and monitoring are essential for optimal performance.
• Material Considerations - Not all materials are suitable for plasma spray coatings, and some may require specific processing conditions or modified parameters to achieve desired results.

Linde AMT's Plasma Spraying Solutions

Linde's TAFA® plasma spray systems combine precise control mechanisms with advanced monitoring capabilities to ensure consistent coating quality. Our systems feature automated parameter management and real-time process documentation, enabling repeatable results across diverse applications.

We provide our equipment with comprehensive operational solutions, including application-specific coating materials and detailed process development. Our engineering team works directly with customers to optimize coating parameters and implement maintenance programs that maximize system performance. We also provide technical training and support to help operators maximize equipment performance and value throughout its service life.

Our Atmospheric Plasma Spraying (APS) solutions:

• Standard Atmospheric Plasma Spray (APS) - This industry-standard process is widely used to deposit various materials, including ceramics, metallic alloys, and cermets. This technique is particularly effective for applying ceramic coatings for thermal barriers and electrical insulation, as well as metallic coatings for oxidation resistance and wear protection.
• Cascaded APS (Sinplex, C+) - This technology uses a series of connected arcs to generate a more stable plasma flow. This enhanced stability leads to better process control, higher coating efficiency, and reduced operating costs, especially when coating large surface areas. This process excels at producing dense thermal barrier coatings (TBCs) with controlled vertical cracks at extended spray distances, making it ideal for complex component geometries. Additionally, when coating silicates onto cold substrates, this method achieves superior crystalline structures compared to conventional plasma spray techniques.
• High-Velocity APS (SG100, 100HE, PlazJet) - This solution offers a middle ground between conventional plasma and HVOF processes. Its unique torch design, powder injection system, and gas flow mechanisms enable faster particle speeds than standard plasma spraying. This technology serves as an alternative when HVOF application isn't practical, and produces higher quality carbide coatings compared to traditional plasma spraying methods. Carbide coatings deposited with this process would be superior to those deposited using a traditional plasma process.
• Shrouded APS (1100 series) - This proprietary plasma spray process utilizes a shrouded design to prevent oxidation of metallic materials during deposition. It is also capable of depositing dense ceramics at much lower substrate temperatures compared to other plasma spray processes. This technique is used for two main applications: creating premium LPPS-equivalent bond coats for thermal barriers and depositing dense dielectric ceramics on temperature-sensitive substrates for electronics.
• Suspension Plasma Spray (SPS) - This technology uses liquid suspensions rather than dry powders as feedstock material. This process, which employs significantly smaller particles, creates distinctive coatings characterized by columnar structures, vertical cracks, and high density. SPS offers a cost-effective alternative to EBPVD (Electron Beam Physical Vapor Deposition) for thermal barrier coatings on aviation components like turbine blades and vanes, while also being suitable for thin, dense ceramic coatings in industrial applications such as printing rolls.
• Low Pressure Plasma Spray (LPPS) - This specialized coating process is performed in low-pressure environments to minimize oxidation while depositing metallic materials. This technique is particularly valuable for applying metallic bond coats to aviation components, including turbine vanes and blades.

Why Partner with Linde?

With over 50 years of experience in thermal spray technology, Linde is more than just an equipment provider — we're a true technology partner driving operational excellence in coating applications. Our process optimization expertise has been refined through countless applications across diverse industries, allowing us to deliver solutions that consistently exceed performance expectations.

Our extensive global service network ensures that customers receive prompt, expert support whenever needed. This commitment to service is matched by our dedication to innovation, where we continuously advance coating technology through research and development. Our teams collaborate with customers to develop solutions that address emerging challenges and requirements, so our partners stay ahead in their respective markets.

FAQs

What materials can be applied using plasma spraying?
Plasma spraying can apply metals, alloys, ceramics, cermets, and various composite materials, with material selection based on specific application requirements.

How long do plasma spray coatings last?
Coating longevity depends on the application conditions and maintenance practices, but properly applied plasma spray coatings can extend component life by several times compared to uncoated parts.

What industries benefit most from plasma spray technology?
Aerospace, power generation, medical device manufacturing, and automotive industries are primary beneficiaries of plasma spray technology, though applications exist across many industrial sectors.

How does plasma spraying compare to other coating methods?
Plasma spraying offers superior coating properties and versatility compared to many alternative methods, particularly for high-temperature applications and advanced materials.