Ceramics, standards and certifications

Dr. Rendtel, even in the technical environment, many people flinch when faced with questions about standardisation or certification. Why is it that norms and standards are mainly perceived as something abstract that actually doesn't really concern anyone?

First of all, I agree with you – when people hear the word “standards”, many go blank; they think that standards are only for specialists. It’s actually a very interesting topic, namely determining measuring methods and the properties of certain materials in a way that’s generally binding. The problem is that this is rarely done in a way that’s understandable to the consumer. One has to observe certain framework conditions so that you’re ultimately not comparing apples to pears. And it can get quite complex...

How could that be changed? Is it possible for a lay person to get a better understanding of the importance of norms and standardisation?

It is actually not that difficult, because the advantages are in fact visible to everyone. You just have to go to the trouble to demonstrate it in practice. For example, we can see that it’s difficult to insert our plugs into an “Italian” socket – it works much better in France or in Sweden. Compliance with standards makes it possible for it to work smoothly everywhere. Or let’s take the European finance industry as an example: it has to a great extent been standardised by the euro. The same applies to technical devices when it comes to determining the properties of materials from all fields. Standards guarantee that when we speak of the “strength” of a material, we all understand the same thing. From comprehensibility, we get to liability and ultimately to the reliability of facts and their relationships.

Technical ceramic – what role does standardisation play here?

That is a question that’s often asked. Here, too, determining the essential properties plays a central role. In our field of non-oxide ceramics, the materials are not yet fully standardised. In the case of oxide ceramics, on the other hand, everyone in the industry who hears the term “KER-710” knows that it refers to an aluminum oxide. We don’t have that in the field of non-oxide ceramics yet. However, the reliability of the properties, as they are then also specified in the data sheets, is – indirectly – ensured by the standardisation of the procedures used for determining these.

What are the main properties that are measured?

The physical properties of ceramics, which play an essential role in their technical application –include strength, hardness, toughness, elasticity, heat conduction and insulation. For example, hardness measurements are carried out using reference materials that have been characterised by an accredited laboratory. The laboratory can use it to check its own measured values and the extent to which its own processes work through means of a comparable standardisation. Strength can be measured using a load cell, which outputs a certain voltage as a measurement signal. This voltage is then converted into a measuring unit to provide precise information regarding the strength.  

The same applies to testing the chemical composition. In this case, the specific values were determined on the basis of test series in which various laboratories took part. In the end, the results were compared and the ones with the most matches were accepted. One can therefore say that in this regard, the results came about through democratic processes, by an act of majority determination.

“From comprehensibility to liability and the reliability of facts and their relationships”

Dr. Rendtel

This means that the laboratories have a central function in this regard ...

Definitely. The values of the properties are determined in the laboratories. To do this, the measuring devices used in the laboratories must be checked regularly and are subject to a clearly defined quality assurance process.

Then we do actually have valid comparisons in every respect, right?

Hang on, there are other different methods that are also being used and they are only somewhat comparable. For example, the strength of ceramic can be determined using either the so-called four-point bend or the three-point bend method. The results of these two methods are usually not congruent: the three-point strength is usually somewhat higher than the four-point strength. So if the procedure is not specified in the data sheet, you basically don’t have any specific information.

What happens in such cases, then?

The market usually regulates this automatically. The customer will not buy anything unless it is made clear to them under which conditions certain values have been determined. If he is not provided with this information to a satisfactory degree, he will usually not buy the product. However, if the information in the data sheet is incorrect, then the supplier is liable for recourse – even if different levels of quality, which were ultimately not adhered to, are defined.

What roles do you yourself play in various functions as moderator and participant in standardisation institutions, committees etc.?   

The entire area of standardisation is very broadly divided into various specialist areas. In our rather small working committee, which I represent, we deal with only 200 standards. There are also a number of other working groups, such as for chemical analysis, in which other standards play a role.

The structure is always the same. In the DIN area, we deal with purely German standards. The next higher level are the EN standards that apply to the European Union, which must then be transposed into national standards by all EU member countries. For us, too, the highest level are the ISO standards, from which the European standards have to be adjusted again. The aim, therefore, is that you as a provider should cover the ISO standards to the greatest extent possible, because that would ensure worldwide distribution of your own products. Another important point is that standards are checked every five years. It’s then decided whether they still correspond to the current state of the art or whether they need to be reworked in this regard.

To what extent can companies benefit from standardisation? What are the advantages for you – possibly also in competition with others?

As I said, those who have the appropriate ISO standards will be accepted in every market in international competition. At 3M, we also have the advantage that we can actively contribute to standardisation – including through myself – e.g. by introducing our own measuring methods into standardisation.

This naturally also involves a certain amount of work for us. Standardisations always originate from the national organisations, where you meet with the relevant experts and read, analyse and check whether procedures have changed. Only as a member of such a working group are you entitled to participate in the corresponding European standardisation work, and from there it continues on to the international level. I myself am chairman of a working group in European standardisation, in which Germany acts as the secretariat. In this role, I am also responsible at a global level as the European representative for the creation of ISO standards.

What does working with standards mean to you? From a perspective of content, what is enjoyable about this work?

There are three main aspects that make the work special for me. First there’s the interaction with other experts, which actually takes place permanently and on several levels. Secondly, you always remain up to date with the “state of the art”, i.e. provided with the latest information on new developments, so you really never miss anything in this regard. Added to this is networking in the specialist circles, including your interaction with colleagues. Put it all together and I really love this job!

Dr. Andreas Rendtel has a doctorate in materials engineering.

After 17 years of research in the field of material properties, especially at high temperatures, and the structure-property relationships of non-oxide ceramics, Andreas Rendtel has been leading all activities in the analytical laboratory of 3M Technical Ceramics since 2002. Dr. Rendtel has performed excellent data collection of the property values of ceramic products as well as many new methods for determining properties.

Dr. Andreas Rendtel has been active in national and international standardisation in the field of measurement methods for determining the properties of ceramic powders and materials since 2005. During this time, he has successfully integrated some of the specific measurement methods used at 3M Technical Ceramics into national and international standards.

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