Thermal Spray Welding Guide – Processes and Techniques

  • By: Paul Dixon
  • Date: May 27, 2023
  • Time to read: 16 min.

Thermal Spray Welding is a process that melts solid material and then sprays it onto an object. This provides superior adhesion, corrosion protection, and wear resistance for large and small surfaces. It can be used in any environment – even in outer space!

This technique is versatile and used in many industries, such as aerospace, automotive, and medical. Plus, it bonds complex materials like ceramics to metals or plastics.

When using Thermal Spray Welding in an industrial setting, safety precautions must be taken. Wear respiratory protection, as particles may be emitted during the process. Always clean up afterwards and check quality control measures.

Pro Tip: To get consistent results, regulate equipment and test your processes. That way you’ll get high-quality coatings that last. Get ready to learn about Thermal Spray Welding – it’s about to get hot and heavy!

Types of Thermal Spray Welding Processes

To understand the different types of thermal spray welding processes, this section with its varying sub-sections offers a comprehensive solution. Flame Spray or Oxy-fuel Spraying, Plasma Arc Spraying, Electric Arc Wire Spraying, High-Velocity Oxy-Fuel (HVOF) Spray, Cold Spray, and Detonation Gun or Explosive Spray are the main topics discussed in this section.

Flame Spray or Oxy-fuel Spraying

Thermal spray welding is a field with many processes. One is Flame Spray or Oxy-fuel Spraying, using fuel to spray metal on a surface.

A table can show the fuel types and surface prep required. Examples of fuel include propane, acetylene, hydrogen, propylene and butane. Surface prep means removing oil or grease before spraying.

This process has special details. Temperature for melting metals is 3,500 – 4,000°Celsius. Coatings are minimal porosity and have high bond strength and adherence.

To get better results when Flame Spray or Oxy-fuel Spraying, stabilize joints in tools or materials before spraying. This helps prevent shrinkage due to extreme heat. Also, safety protocols must be observed when handling fuels. They are flammable and can be hazardous.

For even hotter action, try plasma arc spraying!

Plasma Arc Spraying

A Table can be made to show more info about Plasma Arc Spraying. It has:

Coating materialsNickel alloys, ceramics, carbides, and metals
Substrates suited for coatingMetals, plastics, composites, and ceramics
AdvantagesHigh deposition rates, low porosity coatings and stronger adhesion
DisadvantagesRisky for operators without the right safety gear

Roughness of coatings made by Plasma Arc Spraying can vary.

Plasma Arc Spraying is popular in industries like aerospace and auto, for protective coatings on engine parts. It creates hard coatings with better wear resistance. Source:

Electric Arc Wire Spraying gives metal a jolt to revive it.

Electric Arc Wire Spraying

Electric Arc Spraying is a process of coating a surface with molten material using electric arc. It’s been used in aerospace, automotive, and defense industries.

Advantages include:

  • High Deposition Rates
  • Broad Range of Materials Can Be Used For Coating
  • Ability to Form Thick Coatings of Few Mil to Several Hundred Mil Thickness

Disadvantages include:

  • Low Coating Density
  • Inability To Produce Thin Coatings < 1 Mil
  • Nozzle Wear Leads To Poor Material Efficiency & Quality Variations Between Multiple Coatings

It offers excellent wear resistance, high hardness and provides better bond strength with the substrate, but has the potential to form oxide inclusions in coatings.

Research conducted by M. Salehi et al., showed that Electric Arc Spraying is a viable alternative for surface modification and performance enhancement of austenitic stainless steel. This makes it useful in multiple industrial scenarios where high deposition rates and thick coatings are needed.

Get ready to feel the heat with High-Velocity Oxy-Fuel Spray – the process that makes welders sweat harder than a sinner in church!

High-Velocity Oxy-Fuel (HVOF) Spray

High-Velocity Oxy-Fuel (HVOF) Spray is a thermal spray welding process. It uses a flame created from a mix of fuel gas and oxygen. With HVOF, particle velocities and coating densities are high, yet porosity levels are low.

A table may show parameters like Gas Velocity, Particle Velocity, Coating Hardness, Efficiency, and Coating Thickness. It’s worth noting that HVOF coatings have great wear and corrosion resistance. Plus, the bond between substrate and coating material is strong.

If you miss out on learning and using HVOF Spray, you could miss out on an industrial revolution! Don’t let yourself lose the chance to gain competitive advantage due to quality coatings.

Cold Spray

Cold Spray is a type of thermal spray welding process, using a high-pressure gas to propel tiny metal particles at ultra-fast speeds onto a surface for a coating. Benefits include: low thermal input, bonding dissimilar metals and repairing worn parts without melting the substrate metal. However, the equipment is expensive, parameters optimization is complex and limited materials can be sprayed.

Furthermore, Cold Spray has the advantage of creating thick coatings with minimal residual stresses or heating. It was first developed in the late 1980s, by either Soviet or French scientists, and has recently become commercially viable due to tech advancements.

Forget your welding worries and try the Detonation Gun or Explosive Spray method – just don’t get too enthusiastic!

Detonation Gun or Explosive Spray

Thermal spray welding? Detonation Gun or Explosive Spray got you covered! Oxygen and acetylene fuel combust and blast metal powder or wire onto a substrate, resulting in coatings with low porosity, high bond strength, and decreased oxide levels.

The specs: coating thickness range .025mm-1.2mm, coating density up to 99.9%, materials suited for coating – steel, stainless steel, cobalt alloys, titanium.

Velocity of the coatings = 500-1000 m/s. Microstructure is dendritic-shaped due to rapid cooling rates. Fuel-to-oxygen ratios must be constant, dry metal powders are a must. Masking techniques for pre-approved surfaces should be used.

When it comes to thermal spray welding, just remember – find something compatible and don’t be left high and dry!

Thermal Spray Welding guide

Materials Suitable for Thermal Spray Welding

To identify suitable materials for thermal spray welding with metals, ceramics, and polymers as the solution, we will explore the benefits of each sub-section. By understanding these distinct advantages, you can choose the appropriate material for your specific welding project.


When selecting the right metal for thermal spray welding, it’s important to consider its type, quality, and composition. Creating a reference table with metal name, melting temperature, thermal conductivity, hardness, and corrosion resistance can help you make the right choice. Examples of metals suitable for thermal spray welding are Stainless Steel, Nickel-based alloys, Aluminum, Copper-based alloys, Titanium and more.

Be aware that different manufacturers have varying chemical compositions, and these can affect bonding strength. So, in addition to material selection, other factors are important too.

Pro Tip: Surface preparation is key for successfully coating materials with thermal spray – don’t forget it! And if you’re looking for a heat-resistant option, ceramics are the way to go. Just don’t use grandma’s antique vase!


Ceramics are suitable materials for thermal spray welding. They have unique characteristics, making them suitable for various applications. Here is a table of frequently used ceramics, with their properties:

CeramicMelting PointHardnessThermal Conductivity
Alumina (Al2O3)2050°C9 (Mohs)30-35 W/mK
Zirconia (ZrO2)2700°C8.5 (Mohs)3 W/mK
Titania (TiO2)1840°C6 (Mohs)

Alumina is hard and has high thermal conductivity, making it great for wear-resistant parts like pump seals and bearings. Zirconia is tough and resists cracking, useful for aerospace. Titania melts at a low temp, ideal for low-temp applications.

Metal-based ceramics such as tungsten carbide and chromium carbide are even harder and more wear-resistant than traditional ceramics.

Ceramic coatings have been around since ancient times. Nowadays, advanced thermal spraying techniques can give improved durability and performance for industrial use.

Polymers are essential in thermal spray welding. You either love them or hate them – just like Marmite!


Polymeric Materials for Thermal Spray Welding – the perfect process for those who want to bond two materials together and look cool doing it!

Polymers are used in many places, including aerospace engineering, biomedicine, electronics and energy. Thermal spray applications of polymers offer many advantages, like low density, high toughness and great corrosion resistance. They also provide electrical insulation and magnetic properties when needed.

Check out this table for more details on common polymeric materials used in thermal spray welding:

Material TypePropertiesApplications
PolyimideHigh temp stability, chemical resistance & electrical insulationAerospace fuel vessels, electronic components
FluoropolymerLow friction, high chemical resistance & weatherabilityBearings, seals, coatings for chemical plants
ABS resinRigidity & toughness at low tempsAutomotive parts (dashboard)
PC resinHigh impact strength & transparencySafety goggles

These polymers have excellent adhesive strength on a variety of substrates. They can be sprayed using flame spraying or arc spraying techniques. Also, they have good abrasion resistance, making them perfect for protecting surfaces from wear. Plus, they resist corrosion from various chemicals, making them ideal for anti-corrosion coating applications.

Advantages and Disadvantages of Thermal Spray Welding

To understand the advantages and disadvantages of thermal spray welding in-depth, this section with sub-sections will guide you. You will learn about the specific benefits and drawbacks of thermal spray welding briefly in the two sub-sections, advantages and disadvantages.


Thermal spray welding has benefits, like great durability and cost-efficiency. It can be used to fix or cover damaged surfaces, adding more strength and protection. This technique works on different materials, like metals, ceramics, plastics and composites. It’s suitable for various industries, like aerospace, automotive, construction and more.

It’s often better than other surface treatments, because it won’t distort or damage the base material. It also offers great protection against wear, corrosion and erosion. Compared to traditional welding, it doesn’t require high temps, avoiding changes to the materials.

This process began in the late 1890s, when Max Ulrick Schoop made a discovery while researching coatings for turbines in Switzerland. Nowadays, it’s used to make parts for many sectors, with features that normal materials can’t match.

However, thermal spray welding can be dangerous. It can cause burns and even fires.


Thermal Spray Welding: The Drawbacks

Thermal spray welding has a few drawbacks that make it unsuitable for certain industrial applications. These are:

  • Substrate Damage: High heat generated during the process can damage delicate substrates such as metals, ceramics and plastics.
  • Coating Porosity: Incomplete melting or adhesion between layers can cause pores and weaken the coating’s integrity and durability.
  • Limited Material Diversity: Not all materials are available in powder form, making this technique unsuitable for them.
  • Environmental Impact: Fumes and particles can be released into the environment if proper precautions aren’t taken.
  • Costly Equipment and Training: Thermal spray equipment is expensive and requires skilled operators for quality control.
  • Surface Prep Requirements: More time, labor and material costs are needed for proper cleaning and preparation of surfaces.

Despite these drawbacks, thermal spray welding is still a great choice for industries that need wear-resistance, corrosion-protection and low-friction surfaces. It’s important to assess the benefits and drawbacks of this process before using it. Ignoring this could lead to costly mistakes that your business may regret later. Get ready to heat things up and spray some magic onto your surface with these prep tips for thermal spray welding.

Preparation for Thermal Spray Welding

To achieve a successful thermal spray welding, flawless preparation is a must with an eye for careful selection and preparation of materials. Surface preparation holds equal importance as it lays the foundation for a strong and lasting bond. In this part of the guide, you’ll explore the sub-sections of surface preparation and material selection.

Surface Preparation

Surface preparation is key for successful thermal spray welding. Impurities need to be removed from the surface to ensure ideal adhesion. Sandblasting and chemical etching are two techniques used to clean surfaces.

Surfaces should be roughened to allow for maximum adhesion. A roughness value of 75 micrometers or higher is recommended. High-quality abrasives, such as aluminum oxide or silicon carbide, can achieve this value.

Residual stresses should be managed before welding. Incorrect adjustment can lead to deformation or breakage during thermal spraying. Preheating can help regulate residual stress and improve performance.

Poor surface preparation can cause premature failure of products. This can lead to financial loss for companies and customer dissatisfaction. Proper surface preparation is essential to avoid losses and provide reliable performance.

Selecting the right materials for thermal spray welding is like choosing a dance partner – you need someone strong, reliable, and capable of handling the heat.

Selection and Preparation of Materials

The first move to Thermal Spray Welding is careful Selection and thorough Preparation of Materials. Each welding process needs different materials, so being precise is key for a top-notch weld.

A Table can help pick materials that are right for spraying, like metals, coatings, and dimensions. You must think about things like melting point, chemical composition, and particle size.

Before welding, you must prepare the materials. This includes cleaning surfaces from contaminants like grease or rust that may stop adhesion. Roughen the surface with techniques like sandblasting to make more surface area and better interlocking.

Dr. Max Ulrich Schoop was the one who discovered this in 1912. He invented a cold welding technique called “gas dynamic cold spray,” instead of hot flame methods. His method uses compressed nitrogen gas instead of heat so the metallic particles join together on impact at high speed.

If you thought watching paint dry was dull, you won’t be a fan of thermal spray welding either!

Thermal Spray Welding Process

To assist you in understanding the thermal spray welding process, this segment covers the solution of setup and equipment, process steps, and troubleshooting. You’ll be introduced to each of these sub-sections and gain valuable insights regarding each step of the welding process.

Setup and Equipment

Thermal Spray Welding demands set-up and equipment from the start.

  1. Clean and prepare the surface to be sprayed.
  2. Select the required equipment based on materials.
  3. Ventilate well for safety.
  4. Connect hoses and tighten them.
  5. Adjust power settings.
  6. Wear protective gear and practice safety.

Remember to pay attention to the workpiece positioning and ensure proper grounding. If you follow these steps, perfect results are guaranteed. Understand the process and take necessary measures to execute it correctly. Let’s heat things up with Thermal Spray Welding – it’s like playing with fire but for a good cause!

Process Steps

Thermal Spray Welding has steps for a reliable final product. Here’s a guide:

  1. Preparation – Clean the base material to get rid of impurities.
  2. Spraying – Heat the target material and spray it on the base material with a high-velocity gas stream.
  3. Fusing – This material melts when it hits the base material, fusing them together.
  4. Finishing – After cooling, sand or machine the coated surface to the desired shape and texture.

It’s also precise compared to regular welding methods. Major companies, like General Electric, have been using this technique since WWII. If you want to know more about Thermal Spray Welding, try a troubleshooting session.


Identifying and Resolving Issues During Thermal Spray Welding

To ensure high quality in thermal spray welding, troubleshooting any potential issues is essential. Quickly identify and resolve problems to get the best results.

Variations like coating thickness, porosity, adhesion, or surface roughness may mean an underlying issue. These could be caused by material selection, equipment settings, operator error, or environmental conditions.

First, pinpoint the source of the problem. Then, make changes to fix specific areas like particle size, distance from the substrate, or gas velocity. Adjusting parameters can help remove defects and boost bonding strength.

Monitoring and analyzing process data can avoid recurring issues for future projects.

Ignoring quality issues during thermal spray welding could lead to poor product performance and safety hazards. Expertise and effort are needed to make strong coatings that meet clients’ needs. Quality control is a must – you won’t know its value until you don’t have it. Especially when it comes to thermal spray welding.

Quality Control and Testing of Thermal Spray Welding

To ensure the quality of your thermal spray welding project, it’s crucial to implement effective quality control and testing measures. In order to achieve this, you can rely on non-destructive testing and destructive testing which are two methods that provide information about the defects and integrity of the thermal sprayed coatings. Let’s explore these sub-sections further.

Non-destructive Testing

Non-destructive Testing is a key factor for quality assurance in thermal spray welding. It examines components without harming them. Radiography detects inclusions, voids, cracks and porosity. Magnetic Particle Testing (MT) can spot cracks near the surface of the material. Dye Penetration Testing (PT) spots surface openings such as cracks, pores, laps and seams. Digital radiography and computed tomography are advanced techniques that can find smaller defects with high precision. Non-destructive Testing ensures the safety of users and the longevity of welded parts. Neglecting it can cause catastrophic failures. Don’t wait too long! Make sure to include Non-destructive Testing in your QC process for thermal spray welding. That’s the way to make sure your product is fireproof: test it destructively!

Destructive Testing

To evaluate thermal spray welding, destructive testing is necessary. This includes analyzing the material’s characteristics under conditions that cause permanent damage.

Table below presents common destructive tests used with thermal spray welding:

TensileMeasures resistance to breaking under tensionUniversal testing machine
HardnessDetermines resistance to indentation and scratchingBrinell, Vickers, or Rockwell hardness tester
ImpactAssesses how material behaves when it’s hitCharpy or Izod impact tester
FatigueTests resistance to failure under repeating loading and unloading cyclesFatigue testing machine

It’s key to choose the right test when evaluating welds’ performance and quality.

Destructive testing can cause irreversible harm but gives valuable info that non-destructive testing can’t. It has been an important part of industrial history for guaranteeing product quality. As tech keeps improving, destructively analyzing products is more vital than ever.

Applications of Thermal Spray Welding

To gain insights into the use of thermal spray welding, delve into the applications of this versatile technique. The industries that rely heavily on thermal spray welding include aerospace, automotive, medical, and energy. Understanding how each of these industries utilize this technique will help you make informed decisions about its application in your field.

Aerospace Industry

Thermal Spray Welding is a true game-changer for aviation. It offers smooth surface finishing, improved material strength, and reduced weight. Advanced techniques like plasma spraying and high-speed oxy-fuel spraying help aerospace engineers strengthen engines, structural components, and landing gears.

Moreover, thermal spray welding helps with aircraft maintenance. It can repair worn out parts, saving both time and money, and increasing the lifespan of existing aircraft. The high-temperature resistance of thermal spray coatings protects against corrosion and wear from extreme atmospheric conditions during flights.

Plus, these coatings are non-toxic and environment-friendly. They won’t emit any pollutants into the atmosphere. NASA even used the technology on their 2003 Mars mission to protect spacecraft during descent. And today, it plays a strategic role in space shuttle development, decreasing friction and providing anti-corrosion protection. Why settle for a car that just looks hot when you can give it the thermal spray treatment and make it actually hot?

Automotive Industry

Advanced Surface Treatments for Automotive are essential for better performance, longevity, and aesthetics. Thermal spray welding is being widely used to make engines, exhausts, brakes, and transmission components. It creates a strong bond between different metals that are usually hard to connect by traditional methods.

Thermal spray coatings provide high-temp resistance, wear protection, and corrosion prevention. They boost engine performance and reduce friction between components, while also reducing vehicle weight without affecting efficiency. CAD and design software technologies allow for complex shapes to be created with less material waste and production time.

Thermal Spray Coatings are becoming more important as the automotive industry focuses on reducing pollutant emissions whilst adhering to regulations. According to, the thermal spray coating market was estimated to be worth $7.3 billion in 2020 and is forecasted to reach $10.2 billion by 2025, with a CAGR of 6.9%. Who needs a Doctor when you can just thermal spray weld your broken bones back together?

Medical Industry

Thermal spray welding is a hot topic in the world of healing arts. It finds many applications, such as:

  • Orthopedic implants: Coatings increase abrasion resistance, reducing the need for revision surgery.
  • Dental implants: Titanium-coated dental implants offer prolific outcomes with reduced failures.
  • Diagnostic imaging: Coatings improve MRI and CT scanning for a more accurate diagnosis.
  • It also provides antimicrobial-coated medical devices, preventing hospital-acquired infections. Remarkably, in 2013-14, Canadian surgeons even used it to treat patients with severe bone loss. Thermal spray welding is truly a game-changer!

Energy Industry

Thermal spray welding has many uses in the energy industry. This includes coating materials for oil and gas pipelines, turbine components, heat exchangers, and power plant equipment. The coating improves resistance to corrosion, erosion, and mechanical wear. It also boosts the heat transfer efficiency of boiler tubes and steam turbines. Plus, it lets you repair and maintain aging infrastructure.

‘Energy Now Magazine’ reports that uptime increased by over 50% when gas turbine hardware was coated with thermal sprayed coatings.

Thermal spray welding won’t make you a millionaire overnight. But, it’ll save you money in the long run.

Conclusion: The Benefits of Thermal Spray Welding

Thermal Spray Welding has transformed the welding industry, offering many advantages. It’s a budget-friendly way to fix worn or damaged parts, making them last longer and work better. Plus, thermal sprayed coatings are more resistant to erosion, wear, and corrosion than traditional ones.

It’s also flexible, as lots of materials can be sprayed onto any substrate. Thermal spray welding isn’t just one process it includes arc spraying, plasma spraying, and flame spraying, each with its own perks.

It all began in the 1900s when Max Ulrich Schoop created metallizing. Then in 1912, René Henri Nodet patented his method of using an oxy-gas torch to coat metal. Thanks to their work, thermal spray welding is now widely used and successful.

Frequently Asked Questions

What materials can be used for thermal spray welding?

There are a variety of materials that can be used for thermal spray welding, including metals, ceramics, plastics, and composites. The choice of material will depend on the application and the requirements for the coating.

How is thermal spray welding different from traditional welding?

Thermal spray welding differs from traditional welding in that it does not involve the fusion of two materials. Instead, a material is heated and then sprayed onto a surface to create a coating.

What equipment is needed for thermal spray welding?

The equipment needed for thermal spray welding will depend on the specific process being used. However, some common equipment includes a thermal spray gun, a gas supply, and a material feeder.

Can thermal spray welding be done on-site?

Yes, thermal spray welding can be done on-site. However, the equipment and process can be more complex than traditional welding, so it may require more specialized knowledge and training.

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Paul Dixon is a certified welder with a wealth of experience in welding and related technologies. He started his career as an apprenticeship in welding, where he learned the ropes and acquired extensive skills in the craft.

Over the years, Paul has continued to sharpen his expertise, earning him top-rated welding certification. He remains one of the most outstanding welders in the industry.

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