Product Details Supplier Info More products

Hardide Coatings is developing a coating for gas turbine blades, which will increase their durability and improve their resistance to erosion from hard particles and high-speed water droplets.

This combination of benefits is not feasible using traditional coating methods, including titanium-nitride (TiN) and thermal-spray tungsten-carbide coatings, according to the company.

Longer-lasting turbine blades would offer cost savings to power-generation companies as blades are expensive components and replacement requires costly shutdown time.

Maintaining optimum turbine performance for longer also saves fuel and reduces greenhouse emissions.

Hardide claims that TiN and thermal-spray coatings both give some improvement in part life but the effect of TiN is limited as it is very thin, usually no more than 4 microns in thickness, while thermal spray, despite being thicker, is not as resistant to high-speed water-droplet erosion.

Tests have been performed on the Hardide coating as applied to both steel and titanium substrates, two of the most commonly used blade materials, with positive results.

The liquid-droplet erosion resistance of the coating was estimated to approach that of TiN and, when combined with the ability to apply Hardide up to 25 times more thickly than TiN, the results are said to be a significant development in the ability to achieve optimal performance for gas turbines.

Hardide coatings are produced using proprietary Chemical Vapour Deposition (CVD) technology, which comprises tungsten-carbide nano-particles dispersed in a tungsten metal matrix.

The CVD coating technology is suited to the uniform coating of complex shapes such as turbine blades.

The structure and properties of the Hardide coatings combine ultra-high hardness with enhanced toughness, which are both important for erosion resistance.

Hardness is necessary to resist erosion from solid particles such as scale and soot dust from burning fuel or generated steam.

Toughness and the ability to resist impacts are critical when the blades are hit by supersonic water droplets, which generate shockwaves in the metal surface.

The company claims that its technology allows the hardness and toughness to be controlled over a wide range to achieve the optimal combination for the specific operating conditions of turbine blades; for example, the coating hardness can be varied from 400Hv up to 3,000Hv, depending on the application requirements.

Hardide Coatings

View full profile