Industrial gas and air turbines operate under conditions that accelerate surface wear by design.
High heat, high pressure, constant mechanical load – not exceptional circumstances, just the job. Components don’t fail suddenly. They degrade, steadily, until a planned maintenance window turns into an unplanned outage.
HVAF (High Velocity Air Fuel) thermal spray coating is engineered for this environment. It produces a low-porosity, mechanically bonded coating that resists the degradation mechanisms turbine components face in service. Because the bond is mechanical rather than metallurgical, heat input to the substrate is minimal, preserving the base material’s properties while the coating handles the surface wear.
What’s Happening to Turbine Components in the Field
Australia’s gas and air turbine infrastructure is aging, and the conditions around maintaining it are getting harder. Skilled worker shortages across the energy sector are compressing maintenance schedules, and cost constraints mean fewer operators can absorb an unplanned shutdown. Surface wear that would once have been caught early is progressing further before it’s addressed.
Three mechanisms drive most of the damage:
- Erosion from particle-laden gas streams wears down compressor and turbine surfaces gradually.
- Thermal cycling generates expansion and contraction stress on every start and stop; coatings that can’t flex with the substrate crack and separate.
- Oxidation and hot corrosion break down metal surfaces in the turbine’s high-temperature sections; compounding wear between service intervals.
How HVAF Performs in This Environment
HVAF operates at a controlled temperature of t of 1,800–2,000°C – significantly lower than HVOF’s 2,500–3,500°C which preserves carbide hardness in the coating material. That matters when the substrate is already a high-performance alloy, where hardness retention determines how well the coating holds up under thermal stress and abrasive wear.
Performance figures: up to 5x higher deposition rates and coatings up to 10x thicker than hard chrome. The process also eliminates hexavalent chromium, meeting WHS compliance requirements – relevant for plants managing the transition away from chrome-plated components.
Coating material is matched to the operating zone: tungsten carbide for erosion resistance, chrome carbide for high-temperature wear, aluminium oxide for oxidation and thermal protection. Specific pairings are confirmed through a qualified surface engineer before application.
Turbine Component Restoration
Turbines, compressor rotors, shafts, bearing journals, seal journals, and manifolds are all on the regular repair list. HVAF coating is applied in-house, followed by precision machining – cylindrical grinding, horizontal boring – so a component moves from worn to serviceable without delays.
When replacement parts for older or overseas-sourced equipment carry lead times measured in months, restoration is the faster and more practical path. Components move through coating, machining, and back to site within a planned maintenance window.
Waiting until a component fails removes the options. Engineers managing gas and air turbine assets can talk through their application with us and walk away with a coating specification that keeps the next shutdown planned.
