Development of Zinoco

Developing the next generation of rail corrosion protection

We have a long history of developing and providing corrosion protection systems to the rail industry. Combined with our in-service knowledge of how our products perform in real-life, we set out to design the most robust corrosion protection system available which would also be tolerant to in-service damage.

After the successful development of our previous Railcote product, we understood its limitation in terms of impact and abrasion resistance. So our Research and Development teams got to work developing a superior product. One which retained the damage tolerance, but importantly one which was far more resistant to damage in the key areas of impact and abrasion resistance.

Many options were considered and tested in the laboratory, and some of the comparison test information is presented below.

Corrosion testing

The prohesion test is an industry standard tests which tests the performance of coatings. Here it is used to both test the performance of the coating, but also the damage tolerance by artificially damaging the coating in an area of the test panel. The test samples below have undergone 2,000 hours of testing.

Most coatings offer good levels of corrosion protection where the coating is perfectly intact. However in real-life performance some degree of damage is virtually inevitable over the decades of life often expected from rails. The damage may be from flying ballast, imperfect maintenance operations such as tamping or clip installation, or even from installation itself.

Corrosion testing by Prohesion test comparing different coating performance

The test panels show an uncoated steel panel as a control – which shows severe corrosion and lots of ‘red rust’. 

Each test panel has a calibrated vertical scratch put into its surface in the middle of the panel to simulate damage to the coating

The glass flake epoxy paint protects well where the coating is intact, however where the coating is breached severe corrosion occurs and red rust is clearly visible along with rust creeping under the coating causing it to blister around the damaged areas. The damaged area is not protected from corrosion.

The aluminium coating does not fare well in the accelerated corrosion testing. Red rust is clearly visible in both the coated and also the artificially damaged areas.

Both the Railcote and the Zinoco panels show very good protection in the intact coating areas, but also show no red rust in the artificially damaged areas. This means that even in areas with minor coating damage the steel beneath is still protected ensuring its life is maximised.

Zinoco shows the highest corrosion resistance under accelerated corrosion testing

Durability

One of the key performance attributes desired when developing our Zinoco product was an improved resistance to damage. Whilst the previous coating we offered – Railcote offers good damage tolerance it had limitations in terms of its resistance to damage.

Two key measures were used to assess the performance – Impact resistance and abrasion resistance.

Impact resistance

A bespoke test was developed to mimic real life rail coating damage in association with Network Rail (the UK rail infrastructure owner). This test was then used to assess the performance of various coatings and potential solutions.

The results show the energy required to breech the coating to reveal bare steel beneath, (bare steel is shown with copper colour in images below). The higher the energy needed the more resistant to damage the coating is.

Railcote impact damage resistance testing Zinoco impact resistance testing
Railcote impact energy - ~1Joule Zinoco impact energy – 6-7.5 Joules 


Zinoco shows over 6 times more resistance to impact than previous rail coatings

Abrasion resistance 

In service, particularly around fastenings and within level crossings a rail coating experiences abrasion. Taber wheel abrasion testing was used to evaluate the performance of several coatings. The lower the amount of material that is lost from the surface, the more resistant the coating is to abrasion. Zinoco clearly gives a huge improvement in abrasion performance over previous rail coatings such as Railcote and other historic coatings such as Aluminium.

Taber wheel abrasion test results for Zinoco, Alphatek Hyperloy M1034 (Aluminium) and Railcote

Zinoco provides excellent abrasion resistance to rubbing to protect rails for longer

Zinoco was developed to deliver extremely damage resistant yet also damage tolerant corrosion protection for rails

To find out more get in touch and see how we can extend rail life in challenging environments contact us here.

Product enquiries

PO Box 1, Brigg Road, Scunthorpe,
North Lincolnshire, DN16 1BP.
T +44 (0) 1724 404040 E rail@britishsteel.co.uk