A new laser-based clad coating technology has been developed that promises to help enhance the life of boilers
used in thermal power plants by two to three times compared to currently used surfacing technologies.
Laser cladding is a technique for fusing a coating material on a substrate. It allows materials to be deposited accurately, selectively, and with minimal heat input into the underlying substrate. This process allows for property improvements of the surface of a part, including better wear resistance, thus allowing for the repair of damaged or worn surfaces.
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In advanced supercritical and ultra-supercritical thermal power plants, various parts of the boiler and its accessories such as feeder nozzle tip, re-heater boiler tube bends, burner spreaders often degrade due to severe wear and corrosion at high temperatures and thereby require frequent replacements. Shutdown due to such problems severely affects power production.
To overcome this challenge, scientists from the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous institute of the Department of Science and Technology, Government of India led by Dr. S. M. Shariff, have developed a laser-based clad coating technology (LCCT) that provides adequate protection to the boiler parts ensuring life span improvement beyond two years. An Indian patent has also been granted to the novel technology.
The technology involves fusing a Nickel-based soft matrix with hard metallic carbide particles of tungsten, chromium, or vanadium on steel parts by employing a high-power laser integrated into a multi-axis robot with process monitoring and control. The technology has been successfully tested for feeder nozzle tips of boilers used in NTPC’s 200 and 500 Megawatt thermal power plants at Farakka and Korba.