Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

KorroPad: New rapid test for stainless steel surfaces

15.04.2014

KorroPad is the name given to a new rapid colour test developed at BAM Federal Institute for Materials Research and Testing that enables stainless steel surfaces to be tested inexpensively and rapidly and, most importantly, also by non-specialists.

The pleasure of many designs or components made of stainless steel sometimes declines after a short time. Instead of a beautiful metallic shininess, discoloration and stains may develop after a few months. A few optimists like the emerging ‘leopard pattern’ or lively surface, but most customers simply complain because the appearance does not meet their expectations.

The unexpected discoloration and stains can easily be explained: the protective chromium oxide layer – also called a passive layer – fails to fully develop. However, the stainless steel owes its name solely to this layer. This layer cannot be seen, thus, its defects cannot be recognised. There are a number of reasons for the protective layer to become impaired. The problems are often caused as early as during processing. But faulty semi-finished products, which are currently manufactured world-wide, lead to nonconformities in the materials’ expected corrosion resistance.

The KorroPad test enables steel surfaces to be checked immediately after processing or in the delivery state. In this way, for example, handicraft businesses can protect themselves against costly warranty claims. And this not only involves visual problems since stainless steels are also the material of choice for the manufacture of anchors, dowels and bolts, hazardous material containers and complex chemical plants. These are usually installed in such a way that an error is not obvious at the time, which can lead to safety problems. Thus KorroPad also serves safety in engineering.

Three pads are needed for a test which provides a snapshot of the state of the passive layer. The pads are about the size of a five cent coin and are placed on the stainless steel surface. First, the surface is cleaned with acetone or alcohol and the pads are then lightly pressed onto the surface to be tested. They are removed with a spatula after 15 minutes and placed on a plastic support film where they can be scanned or photographed.

15 minutes is very fast compared to other methods which often take several hours or even weeks. KorroPad also offers another advantage: the component can be further processed after the test or installed at the customer’s premises because it is virtually non-destructive.

Water and a ferric ion indicator are the ingredients of the gel-like pads. If the protective chromium oxide layer is missing on the steel surface, the indicator reacts with the iron ions in the material. The outcome is that the indicator changes its colour and blue dots appear on the slightly yellow pads. Each point indicates a spot on the steel surface where the protective passive layer was not able to develop.

Stainless steels consist of at least twelve percent chromium. The protective layer on the surface needs oxygen and water (from humidity) and a clean, bare metallic surface to be able to develop. The passive layer then seals the surface. If the protective layer cannot be formed all over the surface, corrosion occurs.

"KorroPad helps people help themselves," says Andreas Burkert who, together with Jens Lehmann, has developed the test at BAM. Visually the surfaces always look blank at the beginning. But do the components really provide what the material’s name promises in practice? Many factors play a crucial role: How has the surface been processed? How have the weld seams been treated? Are the alloying elements evenly distributed? Burkert continues: "It is like baking a cake: The ingredients alone are not enough! The dough needs to be stirred properly and the subsequent heat treatment in an oven must be at the right temperature over the right time."

Meanwhile, some companies have already used KorroPad. The quick method is also included in the teaching curriculum in vocational schools and at universities. KorroPad visualises material properties that are otherwise hidden to the human eye. And KorroPad shows students how important it is to adhere to the rules of processing. Because standards alone will not lead to a safe technical application, what counts is what actually has been implemented in practice.

Pads can be ordered via BAM’s webshop. Of course, end users can also order the test itself if needed. 100 pieces cost 390 euros, smaller packages will also soon be offered due to numerous requests. A test with three pads costs about 12 euros. The process is so simple that even laymen can perform it. A private developer can quickly and inexpensively check to see if his new stainless steel railings are of flawless quality.

The project 17136 N/1 of the Research Association GfKORR e.V. was funded by the Federal Ministry for Economic Affairs and Energy via AiF within the Industrial Research Promotion Programme (IGF) based on the German Bundestag’s decision.

Contact:
Dipl.-Ing. Jens Lehmann
Division 6 Materials Protection and Surface Technologies
Email: Jens.Lehmann@bam.de

BAM is a senior scientific and technical Federal Institute with responsibility to the Federal Ministry for Economic Affairs and Energy (BMWi).

Dr. Ulrike Rockland | idw - Informationsdienst Wissenschaft
Further information:
http://www.bam.de

Further reports about: BAM Economic Energy Materialforschung ions processing surfaces

More articles from Materials Sciences:

nachricht 3-D-printed structures 'remember' their shapes
29.08.2016 | Massachusetts Institute of Technology

nachricht Crystal unclear: Why might this uncanny crystal change laser design?
29.08.2016 | National Institute of Standards and Technology (NIST)

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Virtual Reality: 3D Human Body Reconstruction from Fraunhofer HHI digitizes Human Beings

Scientists at the Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, HHI have developed a method by which the realistic image of a person can be transmitted into a virtual world. The 3D Human Body Reconstruction Technology captures real persons with multiple cameras at the same time and creates naturally moving dynamic 3D models. At this year’s trade fairs IFA in Berlin (Hall 11.1, Booth 3) and IBC in Amsterdam (Hall 8, Booth B80) Fraunhofer HHI will show this new technology.

Fraunhofer HHI researchers have developed a camera system that films people with a perfect three-dimensional impression. The core of this system is a stereo...

Im Focus: Streamlining accelerated computing for industry

PyFR code combines high accuracy with flexibility to resolve unsteady turbulence problems

Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...

Im Focus: X-ray optics on a chip

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.

In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...

Im Focus: Piggyback battery for microchips: TU Graz researchers develop new battery concept

Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.

Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...

Im Focus: UCI physicists confirm possible discovery of fifth force of nature

Light particle could be key to understanding dark matter in universe

Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The energy transition is not possible without Geotechnics

25.08.2016 | Event News

New Ideas for the Shipping Industry

24.08.2016 | Event News

A week of excellence: 22 of the world’s best computer scientists and mathematicians in Heidelberg

12.08.2016 | Event News

 
Latest News

Cancer: Molecularly shutting down cancer cachexia

31.08.2016 | Life Sciences

Robust fuel cell heating unit developed

31.08.2016 | Power and Electrical Engineering

Algorithms Offer Insight into Cellular Development

31.08.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>