What Materials Are Used For Metal Spray Coating?
In the case of metal parts that wear off or corrode, it may be expensive and time consuming to replace the parts. The place where metal spray coating comes in is to revive old parts and provide some additional protection to new ones.
It can be a pump shaft that you have to fix or it can be the attempt to make molds last longer, but the proper choice of coating material matters all. This article explores what goes into these coatings, how they work and which materials fit each job best. Read on to learn more.
Why Material Choice Matters
Not all coatings are created equal. Some must handle extreme heat while others need to fight off rust or friction. If you choose the wrong one, parts can still fail early. Picking the right material helps you:
- Extend part of life and cut downtime.
- Reduce costs on replacements and maintenance.
- Improve performance by adding special properties like conductivity or traction.
At CY Thermal Spray Coating, engineers have spent over 40 years helping industries match the perfect coating to their parts.
Common Materials Used in Metal Spray Coating
Various materials are used for different purposes. Following important types of metal spray coating and what each one can offer to the table:
1. Self-Fluxing Alloys (Nickel- or Cobalt-Based)
These finishes are the work-houses of wear and corrosion coating. They fuse and melt on the surface forming a coarse tough layer.
Best for:
- Pump shafts, valves, and bearings.
- Machinery exposed to friction or chemicals.
Benefits:
- High toughness and hardness.
- Good anti-corrosion and anti-galling.
- May be smoothed to a mirror finish.
Some common examples: Co-Cr-W, Ni-Cr-B-Si alloys.
2. Carbide Coatings (Tungsten and Chromium Carbide)
When you require incredibly high wear resistance, then this is your choice. Carbide finishes act as a shield to your equipment. They are able to operate under high temperature and speed.
Best for:
- Wire drawing rollers, cutting tools, and extrusion dies.
- Environments with abrasive dust or slurry.
Benefits:
- Extremely hard and dense.
- Outstanding resistance to abrasion and erosion.
- Long life even under high heat.
Typical compositions include WC-Co and Cr₃C₂-NiCr.
3. Ceramic Coatings:
Ceramics may be fragile though when it comes to metal spray coating they are strong and protective. These finishes are resistant to corrosion and chemicals as well as heat. They are perfect when metals would otherwise fail.
Best for:
- Insulating surfaces and high-temperature zones.
- Components that need electrical or thermal barriers.
Benefits:
- Excellent corrosion and oxidation resistance.
- Great insulation properties.
- Smooth, clean finish for reduced friction.
Common materials: Al₂O₃ (aluminum oxide), Cr₂O₃ (chromium oxide), and ZrO₂ (zirconia).
4. Metallic Coatings (Zinc, Aluminum, Stainless Steel, Inconel)
The heroes when corrosion is your number one foe; consider bridges and pipelines or offshore gear. They are used as a protective coating that covers the underlying base metal.
Best for:
- Structural steel, tanks and marine assets.
- Repairing rusted or pitted parts.
Benefits:
- Massive corrosion resistance (particularly zinc and aluminum).
- Reflective finish increases the effect and resistance to heat.
- Easy to apply and repair.
These layers are also used as bond coats then overlaid with harder layers.
5. Specialty Coatings (Copper, Bronze, Molybdenum)
Some jobs call for something unique. For instance, copper or bronze coatings provide conductivity, while molybdenum adds slip and wear resistance.
Best for:
- Electrical contacts, sliding parts, and anti-seize surfaces.
Benefits:
- Custom properties for specific performance goals.
- Good for both new parts and repair work.
Matching Material to Process
Not every coating material fits every process. Here’s how they usually pair up:
- HVOF (High-Velocity oxygen-Fuel): Ideal when it comes to the carbide coating- thick and extremely hard.
- Plasma Spray: This is the most suitable when surfaces on ceramics and metals require a fine finish.
- Arc or Flame Spray: This is used on zinc, aluminum and stainless steel.
- Spray Welding: Ideal in self-fluxing alloys in which the fusion and rebuild strength is important.
Each process affects coating density, bond strength, and cost so expert selection counts.
Choosing the Right Material
Wondering which coating your part needs? The same question is posed to many engineers and maintenance teams. The good thing is that, with a bit of guidance, it becomes easy to reduce it. The trick is to think where your part is, what forces are acting upon it and how long it is worth bearing. Here’s a simple guide:
- Rust or salt exposure? Go for zinc or aluminum coatings. They are like bodyguards of your metal and they sacrifice themselves in favor of the base steel that is underneath. Ideal in the marine or outdoor setting where the enemy is moisture.
- Heavy wear? Choose tungsten carbide. It is hard as nails and it is capable of friction, wear and tear or speeding. Just imagine it like roller-armor plating of dies and other moving mechanisms that are being battered daily.
- High heat? Pick ceramic or Cr₃C₂-NiCr coatings. The materials counter the severe temperatures and retain their strength where other coatings would melt or crack. They are excellent in furnaces, moulds or components close to areas of high heat.
- Electrical conductivity? Go with copper or bronze coatings. They not only resist wear but also let electricity or heat flow freely. You’ll often find them on conductive parts, connectors and slip rings.
- Dimensional repair? Apply nickel-based spray welding alloy. It restores damaged components to their natural dimensions and even gives them a tough, resistant to corrosion surface. This will save both time and money that would have to be spent replacing the whole component.
Selecting the correct option isn’t guesswork; it’s engineering. That’s why it helps to consult professionals who understand both materials and operating conditions. At CY Thermal Spray Coating, technicians evaluate the working environment, temperature, and part geometry to recommend the ideal combination.
Quality and Testing
A coating is only as good as its preparation. Before applying metal spray coating, the surface is grit-blasted to ensure a strong bond. CY uses:
- Bond coats (like Ni-Al) for better adhesion.
- Adhesion and hardness tests to ascertain the strength of coating.
- A fine level of precision grinding and polishing to attain smooth and accurate finishes.
The result? Coatings that remain in place when it is under pressure and extend equipment life.
Real-World Payoff
Companies that use professional metal spray coating often see:
- Up to 5× longer part life.
- Reduced downtime due to fewer breakdowns.
- Lower maintenance costs over the long term.
Such advantages become actual savings and improved productivity something all engineers and project managers can enjoy. See our Coating Services and Case Studies page to find out more about the other coating processes and stories about success.
Final Thoughts:
When choosing the material to use in coating metal, it is not only a technical decision but a business decision. The right coating reduces the expense, enhances productivity, and maintains smooth running of machines.
You need to repair old components or enhance new components, CY has been doing this all over decades to ensure that your money spent does not go to waste. Looking for expert advice? Visit CY Thermal Spray Coating Services to explore solutions and also check out case studies and request a quote.
FAQs
Question 1. Which metal spray coating material is the most rust-resistant?
Answer: The most resistant to rust is zinc and aluminum. Even where the marine or outdoor environment is concerned they create a protective layer that protects steel against corrosion.
Question 2. Can stainless steel be sprayed to repair parts?
Answer: Yes! Stainless steel can be applied using arc or flame spray to rebuild worn surfaces and restore corrosion resistance.
Question 3. Which is more wear-resistant, ceramic or metal coating?
Answer: The ceramic is highly resistant to heat and corrosion. The metal layer (comprising carbide) is more resistant to the overweight or friction.
