What happens when a finished part needs a super hard coating, but thermal spraying just won’t cover it? Liz Nickels paid a visit to Hardide Coatings in Bicester, UK and found out how a Cold War tungsten coating technology has become one of the most effective ways to make the whole surface of complex metal components extra hard.
The technology behind Hardide Coatings’ chemical vapor deposition (CVD) technology has an interesting history, originating as it did in the pre-perestroika Soviet Union. Technical director, Yuri Zhuk, tells the story. ‘Materials in general were one of the priorities in the Soviet Union – because for electronics or space sputniks or nuclear reactors you need materials with special properties,’ he explains. ‘The space race required very extreme materials, capable of withstanding extreme temperatures, extreme loads and so on. So at the time there was quite a lot of innovation and new developments in materials–but very little of that was commercialized, due to Cold War secrecy.
‘As a result, there was a risk that this research would never be published, and that potential users would never know that such wonderful technology exists. However, this situation changed in the early nineties with the collapse of the Iron Curtain – but then funding for research institutes in the former Soviet Union was dramatically cut. As a result, researchers were allowed and even encouraged to find commercial use for their technologies. So that's how it started.’
Hardide Coating's CVD technology is a way of producing a coating based on tungsten carbide that, unlike thermal spraying techniques, allows the coating to be completely pore free, and combine hardness with toughness, as a result, extremely abrasion, corrosion, and acid resistant.
This article appeared in the July/Aug issue of Metal Powder Report.
