cold spray technology scientistsFrom left, research associates Dmitry Dzhurinskiy, Volf Leschynsky, IDIR associate director Emil Strumban, and technician Damir Ziganshin examine a bottle of the powder composition being used to coat repair welds at the top of the Hanna Street water tower.

Spray technology extends life of water tower

The life of the Hanna Street water tower may be extended dramatically thanks to an exclusive low pressure cold spray process developed by scientists at the university’s Institute for Diagnostic Imaging Research.

About three weeks ago, Enwin workers began re-welding corroded seams of the water tank at the top of the tower, which holds about 1.5 million litres of water and helps regulate pressure in the municipal water system. Following behind them were workers trained by IDIR staff on how to coat those welds using a portable cold spray machine that spreads a mixture of powder materials including zinc, aluminum and some ceramic materials.

 “It’s very similar to a paint spraying process, but spraying a metal-ceramic powder composition instead,” explained physicist Emil Strumban, IDIR’s associate director. “The supersonic nozzle, which is the heart of the cold spray machine, accelerates the particles to very high velocities and actually embeds them into the surface of the welded joint. We’re actually building up the coating as it’s applied, and the technology allows us to form coatings with strong anticorrosion properties.”

The last time the 58-year-old tower was repaired was in the late 1980s according to Gary Rossi, Enwin’s director of water production.

“Because the microstructure of the heat affected zone around the weld changes considerably, it becomes susceptible to corrosion and the welds can rust very quickly,” said Strumban. “Our corrosion resistant coatings are designed to prevent the welds from rusting, and are probably the most efficient way to save them from corrosion.”   

The job, which involves welding and spraying about 250 meters of seams, was expected to wrap up yesterday.

“I have no worries about its longevity,” John Wladarski, Enwin Utilities’ vice-president of operations said of the proprietary technology, which IDIR has used in a variety of applications with such industry partners as Ford, Chrysler, Alcoa, Westinghouse Electric and the U.S. Army research lab. “I understand the sprayed coating is extremely resistant to corrosion and substantially extends the life of the welded joints.”

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