Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists develop life-saving chrome

21.09.2005


British scientists develop new way of using chrome that doesn’t put workers’ lives at risk



British scientists have developed a safer and more versatile alternative to chrome electroplating, the coating found on vintage car bumpers, steel camshafts, and fixtures such as door furniture and light fittings.

Chrome electroplating protects from corrosion and adds an aesthetically pleasing sheen, but chromium comes with serious health risks and chromium compounds have been shown to cause cancer.


Speaking at an Institute of Physics conference in Chester, UK, Professor Robert Akid warns that workers are being exposed to chromium compounds that are potentially cancer-causing and says that a safer alternative is much needed. He told the conference, Novel Applications of Surface Modification, organized by the Applied Physics and Technology Division of the Institute of Physics, that he and his colleagues are developing an alternative that will not only be safer but cuts down on costs by reducing the numerous processing stages associated with conventional electroplating.

Professor Akid, who is Head of the Structural Materials & Integrity Research Centre at Sheffield Hallam University, is developing a so-called "sol-gel technology" which is a colloid with nanoparticles in a solvent that can form a gel. A metal object is sprayed with or dipped into the sol-gel system and it quickly forms a gel-like layer on the object’s surface. The solvent is then removed by evaporation and the coating cured, or hardened. Akid says that the sol-gel approach can be used to coat a wider range of metals than electroplating methods.

Professor Akid said: "These inorganic-organic hybrid coatings have the potential to become an effective method of producing an alternative low-cost anti-corrosion or functional coating. The technology can be formulated and cured to give highly corrosion resistant, ceramic-based coatings. The method uses a range of cure temperatures and coatings are cured rapidly. The chemistry of the formulations has also been developed to provide sol-gel solutions that have a good shelf life."

There are technical issues yet to be addressed by the Sheffied team, however. For instance, a pre-requisite for such anticorrosion coatings on metals, such as aluminium and other metal surfaces, including zinc, stainless steel, and magnesium, is that they should be sufficiently thick, to give adequate lifetime and hard enough to be protected from scratching and abrasion.

Until now, sol-gel derived layers can be formed only up to two or three hundred nanometers in thickness with a single-dip. Akid explains that double dipping to produce multiple coatings is possible but this has the potential drawback of a reduction in coating properties.

Akid said: "The new type of protective coatings not only have high corrosion resistance and don’t easily release their constituent ions into the environment, but are also non-toxic." Akid and his colleagues have used sol-gel mixtures that produce aluminium oxide and silicon oxide coatings with a chemical component that allows them to bind to the metal component’s surface.

The team’s preliminary corrosion tests, including so-called potentiodynamic polarisation in which an electric current is used to induce corrosion showed that the coating possesses excellent corrosion resistance properties compared with uncoated samples and other pre-treatments. The researchers have also carried out mechanical tests and have shown with a simple scratch and bend tests that the coatings exhibit very good adhesion to the substrate.

As a further test of the durability of the coating, the researchers also immersed coated components in an exfoliation solution consisting of nitric acid and chloride with very high acidity, pH1. This simulates the kind of corrosion that aluminium alloy aerospace components might experience, albeit an accelerated test. Akid explained that their test results compared well with similar tests on bare and chromic acid anodised samples. The sol-gel hybrid coating showed little attack even after almost 200 hours immersion. The chromic acid anodised components were pitted after this time and so failed the test, while the bare simple was extremely corroded. The team used scanning electron microscopy (SEM) to identify the nature of the attack, general or localised corrosion.

David Reid | EurekAlert!
Further information:
http://www.iop.org

More articles from Physics and Astronomy:

nachricht UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire

nachricht NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>