Thermal spray technology is a critical surface treatment method widely used in modern industries. Different operating conditions impose various performance requirements on coatings, ranging from high-temperature resistance and wear resistance to corrosion protection and oxidation resistance. The selection of an appropriate thermal spray process directly affects the service life of components and the operational efficiency of equipment.

The following content introduces typical application scenarios of thermal spray technology across major industries, along with practical guidance for coating selection and maintenance.

Steel & Metallurgy Industry

In the steel and metallurgy industry, equipment is often exposed to extreme conditions, including high temperatures, heavy loads, and corrosive atmospheres. Thermal spray technology is commonly applied to critical components such as blast furnace tuyeres, continuous casting molds, and rolling mill rolls, providing heat-resistant, wear-resistant, and thermal shock-resistant coatings to extend service life.

For example, in continuous casting production lines, nickel-based or cobalt-based alloy coatings applied to copper plates of molds can effectively resist molten steel erosion and thermal fatigue.

When selecting coatings, key factors such as coating adhesion strength and thermal shock resistance should be considered. Regular inspection of coating thickness and surface conditions is also essential to prevent production interruptions caused by localized coating failure.

For more industry-specific solutions, please refer to our Steel & Metallurgy Application Guide.

General Machinery Industry

General machinery includes pumps, valves, compressors, hydraulic components, and other mechanical equipment. The main failure mechanisms of these components are usually wear, corrosion, and cavitation.

Thermal spray coatings such as chromium oxide, aluminum oxide ceramic coatings, and metal-ceramic composite coatings can significantly improve surface hardness, wear resistance, and chemical stability.

For example, piston rods and plungers coated with tungsten carbide coatings can achieve several times higher wear resistance compared with untreated surfaces.

During coating selection, factors such as operating medium characteristics (chemical corrosion, temperature, and pressure) and movement conditions (sliding, impact, or friction) should be carefully evaluated. After spraying, precision machining may be required to meet dimensional accuracy requirements.

During operation, abnormal impact should be avoided, and sealing surfaces should be regularly inspected for scratches or coating damage.

More information is available on our General Machinery Solutions page.

Aerospace Industry

Aerospace components require extremely high levels of reliability, lightweight design, and resistance to harsh environments.

Thermal barrier coatings (TBCs) are widely used on turbine blades to reduce substrate temperatures and improve engine efficiency. Abradable seal coatings are applied to compressor casings to control blade tip clearance and reduce fuel consumption.

In addition, landing gear components often use environmentally friendly alternatives to hard chrome plating, such as high-velocity oxygen fuel (HVOF) sprayed tungsten carbide coatings, to achieve excellent wear resistance and corrosion protection.

When selecting coatings for aerospace applications, strict compliance with aerospace material standards is required. Thermal expansion compatibility between the coating and substrate must also be considered.

Maintenance procedures should include professional coating thickness measurement and bond strength evaluation equipment, with repair processes carried out according to approved maintenance specifications.

For more details, please visit our Aerospace Coating Solutions section.

Mining Machinery Industry

Mining equipment, including crushers, conveyors, and excavator buckets, operates under severe conditions with continuous abrasion and impact loads.

High-hardness wear-resistant coatings, such as chromium carbide and tungsten carbide coatings, provide effective protection for base materials, reducing downtime and replacement frequency.

For example, crusher hammer heads treated with wear-resistant thermal spray coatings can achieve significantly extended service life.

When selecting coatings, a balance between hardness and toughness is essential. Excessive hardness may result in brittleness and coating cracking under impact conditions.

After installation, coatings should be inspected regularly for cracks or surface damage. Wear levels should be monitored during operation, allowing timely repair or recoating when necessary.

More information can be found in our Mining Machinery Application Guide.

Oil & Gas Industry

The oil and gas industry involves drilling, transportation, and refining processes where equipment is frequently exposed to high pressure, sulfur-containing environments, and abrasive particles.

Thermal spray coatings, including corrosion-resistant alloy coatings (such as Hastelloy and Inconel) and wear-resistant coatings, are widely used to protect drilling tools, valves, and pipeline inner surfaces.

For example, tungsten carbide coatings applied to downhole tools can significantly improve resistance against erosion and abrasive wear.

When selecting coatings, it is important to evaluate operating conditions including chemical composition, flow velocity, temperature, and resistance to stress corrosion cracking in hydrogen sulfide environments.

Regular inspection of wall thickness and coating integrity is recommended to ensure long-term equipment reliability. Damaged areas should be repaired promptly to prevent further degradation.

For detailed solutions, please refer to our Oil & Gas Coating Applications page.

Frequently Asked Questions

How should coating materials be selected according to operating conditions?

The first step is to identify the primary failure mechanism, such as wear, corrosion, high-temperature oxidation, or thermal fatigue.

Then, coating materials should be evaluated based on technical parameters including hardness, bond strength, temperature resistance, corrosion resistance, and wear performance.

For critical applications, sample testing under actual working conditions is recommended to verify coating performance.

What surface preparation is required before thermal spraying?

Surface preparation usually includes:

• Degreasing and removal of contaminants
• Abrasive blasting to increase surface roughness
• Cleaning and drying before spraying

Proper surface preparation ensures strong mechanical bonding between the coating and substrate.

Specific parameters should be determined according to the substrate material and coating requirements.

Is a thicker coating always better?

No. Coating thickness should be controlled according to design requirements and process limitations.

Excessive thickness may increase internal stress, reduce bonding strength, and cause coating cracking or delamination.

The recommended thickness range should always be followed to ensure uniform coating quality and long-term reliability.

Does thermal spray coating require post-processing?

It depends on the application.

Many thermal spray coatings require additional machining processes, such as grinding, polishing, or honing, to achieve required dimensional accuracy and surface finish.

However, some coatings, such as abradable seal coatings, are designed to remain in their as-sprayed condition.

How is coating quality inspected?

Common inspection methods include:

• Coating thickness measurement (eddy current testing, microscopy)
• Bond strength testing (pull-off test, scratch test)
• Hardness testing
• Metallographic analysis

The specific inspection requirements depend on application standards and customer specifications.

How can localized coating damage be repaired?

Small damaged areas can usually be repaired by:

1. Removing damaged coating through grinding or surface preparation
2. Cleaning the repair area thoroughly
3. Applying new coating material
4. Ensuring smooth transition between the repaired area and original coating

For large-scale damage, complete removal of the existing coating and full recoating may be required.