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 Strange but true: Turning a material upside down can sometimes make it softer
20.10.2017 | Universitat Autonoma de Barcelona

nachricht Metallic nanoparticles will help to determine the percentage of volatile compounds
20.10.2017 | Lomonosov Moscow State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>