Metal spray coating, often called thermal spraying, forms protective layers by projecting molten or semi-molten particles onto a prepared surface. The process upgrades components, adding wear, heat and corrosion resistance while restoring dimensions. The layered build means thermal sprays suit many part sizes and industries.

How Thermal Sprays Work

Powder or wire feedstock is melted and accelerated by flame, arc, plasma or HVOF, and then forms a dense lamellar coating. Variants include flame spray for rebuilds, arc wire for rapid coverage, plasma for temperature-resistant ceramics and HVOF for hard, low-porosity carbide layers.

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Materials, Properties and Sealing

Typical feedstocks include tungsten carbides for abrasive wear, chromium oxide or alumina ceramics for insulation, and stainless or aluminium alloys for corrosion resistance. Coatings from thermal sprays can be ground to fine tolerances and sealed to reduce porosity where liquids or gases are present.

Correct surface preparation matters. Degrease, grit-blast to a controlled profile and mask critical bores before spraying. Thickness is verified with gauges, and adhesion is usually proved by standard pull tests.

Where It Helps and What to Check

Thermal sprays prolong the life of pump shafts, hydraulic rods, turbine parts and mould tools, while adding low-friction or anti-corrosion skins to rollers and valves. They also allow fast turnaround because only the worn surface is renewed.

When specifying, match coating chemistry to the environment, confirm service temperature limits and plan the post-coat finishing route so the part returns to service quickly and reliably.