Breakthrough in coating technology

Citation

(2001), "Breakthrough in coating technology", Anti-Corrosion Methods and Materials, Vol. 48 No. 6. https://doi.org/10.1108/acmm.2001.12848faf.002

Breakthrough in coating technology

Breakthrough in coating technology

Keywords: Hardide Coatings, Coatings, Gas phase

A breakthrough environmentally friendly coating technology which claims to provide solutions to problems not solved by any existing processes is reportedly poised to have a major impact on the world-wide engineering sector as licenses become available for the first time.

Known as Hardide and originally developed in Russia, the gas phase process is believed to be a world first in that it is claimed to be the only low temperature, super hard coating technology to be able to coat "out of sight" surfaces and complex shapes uniformly.

Hardide, the composition of which is based on tungsten carbide, is also said to be able to challenge all existing coating methods such as PVD, thermal or plasma spraying due to a combination of credentials, which are claimed to be:

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  super hardness (up to 3500HV) outperforming spray coatings, hard chromium, nitriding and cementation by a ratio of three to one;

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  an ultra low dry friction coefficient (from 0.1 to 0.2) offering enhanced self lubricating capabilities;

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  unrivalled chemical and corrosion resistance to water, salt and acids;

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  a wear factor of between 40 and 100 times less than case hardened steel – and up to ten times less than cemented carbide hardmetal;

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  outstanding erosion resistance, outperforming steel by a factor of ten when subjected to water/sand jet tests at 10m/sec and by 100 when speed increased to 20 or 30 m/sec;

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  porosity of less than 0.04 per cent;

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  coating thickness with a variability range from 5 to 30 microns.

Nor does the Hardide technology produce just one but a family of more than 20 coatings offering a variety of parameters to meet specific application requirements. All these coatings can be produced at one plant, while the composition and structure of each is controlled by process conditions.

According to Hardide, where factors have previously dictated the use of costly hardmetal (also called cemented carbide) or special case hardened steel these can now make way for coated steel which is easy to machine and costs less.

Yet another feature claimed of Hardide is that during the coating process Hardide fills and closes micro cracks and restores the shape and size of worn parts, while the smooth nodular texture ensures quality finishing results.

The technology, which is said to have the potential to replace most traditional coating methods including heat treating, claims an immediate benefit for internal die tools as it reportedly eliminates traditional problems such a droplets sticking to the extrusion die and scratching the extrusion section surface.

We are also informed that Hardide's non-porous coating can also facilitate the release of any moulded product in that it has non-stick characteristics. It is also reported to be inert and so does not interact with other materials.

Hardide report that accelerated wear tests showed that five pairs of piston sleeve hydraulic parts coated with 30 microns of Hardide outperformed case hardened piston sleeves by a factor of seven when subjected to the rigours of oil with diamond abrasive grit. The company also states that other more common abrasives like sand would make the difference much more significant.

The company believes that with the potential to dramatically reduce manufacturing and maintenance costs – Hardide coated parts can last up to 100 times longer – the process offers a major new technological weapon for industrial companies fighting cheap imports from China, Latin America and the Pacific Rim.

It has taken 20 years for Hardide to come to the coatings market after being extensively researched and developed, initially in Russia and more recently in Oxford, England, where the first application development centre in the West and only the second in the world – the other being in Moscow – has just been unveiled and from where samples can be obtained on request.

Heading up the team at the new UK Centre of Excellence are two leading Russian scientists. Professor Yuri Lakhotkin, technical director of Hardide Ltd, is one of the world's leading authorities on chemical vapour deposition used in the Hardide process; while Dr Yuri Zhuk, Hardide Ltd's managing director, is not only a renowned academic but also an expert in international technology transfer – and a prime mover in bringing Hardide's benefits to the West.

Hardide believes it has the potential to provide major benefits for coating companies serving all industry sectors, with specific areas already pinpointed including automotive, aviation, and construction and agricultural equipment.

In the automotive sector, the fact that Hardide is said to provide a slippery low friction surface without lubrication will make it attractive to crankshaft bearing manufacturers among others. The extreme wearability claimed of the product could make it ideal for components such as gudgeon pins and precision parts such as those found in fuel injection systems where there are very strict tolerance issues.

Power steering boxes and suspension components are said to be others in a seemingly endless list of potential applications in the automotive arena.

The company also believes that its technology scores heavily over hard chrome coating traditionally used in the manufacture of construction and agricultural equipment. In the company's opinion, not only is the Hardide process environmentally-friendly, whereas chrome salts solution is so dangerous it is due to be restricted in Europe, it also offers a coating that is three to four times harder.

Hardide's composition, structure, coating method and applications have been protected by international patents covering 67 countries including the USA and Canada, the EU, Japan, China, Korea, Brazil and Mexico.

Speaking to ACMM, Graeme Hitchen, business development manager said "What we have with Hardide is not another coating but a solution to problems not solved by existing materials. We are looking for suitable partners among the coating industry world wide to ensure that Hardide achieves its global potential."

Details available from: Hardide Coatings. Tel: +44 (0)1865 309677; Fax: +44 (0)1865 309676; Web site: www.hardide.com