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In the Laboratory for Precise Measurements of Length, LFSB, which is now the Croatian National Laboratory for Length, unique roughness reference standards were developed in the year 1986. Because of the world-class quality of those standards and their measuring features, the same were sold in several European countries, and today they, among others, are used as roughness reference standards in Italy, Slovenia and Croatia. However, especially in the last decade, there was significant progress in the field of nanotechnology that led to the development of new measuring equipment. The above-mentioned standards due to their size, production technology and measuring features cannot fully meet metrological requirements in the field of nanometrology, i.e. they are not compatible with scanning probe microscopes. Therefore, it was decided to search for possible limitations in the procedure of groove depth measurements on the LFSB standards. In order to include as many measuring devices as possible, i.e. measurement methods, in this research, in 2008 the LFSB launched EURAMET Project 1012 'Limitations of methods for measuring the depth of the groove' in collaboration with national metrology institutes of Italy and Egypt. In this paper the results of measurements performed within the project are presented, and based on the obtained results, the advantages and limitations of the LFSB standards have been discussed, with recommendations for their improvement.

This paper presents the research regarding the influence of glyoxal on electrochemical and corrosion behaviour of austenitic stainless steel in water. For this purpose, model solutions containing glyoxal in water in concentrations ranging from 0.1 to 1 % were prepared. Spring water was used as control electrolyte. From the potentiostatic polarisation data (using the standard three-electrode system), the corrosion current (i corr ), corrosion potential (E corr ) and polarisation resistance (R p ) were calculated. The research included also the conductivity, total dissolved soils, salinity, resistivity and pH, absolute potential, and relative potential of model solutions. The presence of glyoxal at the highest concentration of 1 % in the water solution has accelerating effect on corrosion.Key words: stainless steel, localized corrosion, water, glyoxalIn dieser Arbeit wurde die Auswirkung des Glyoxals auf das elektrochemische und korrosieve Verhalten von austenitischem Edelstahl im Quellwasser untersucht. Für diese Erforschung wurden Wasserlösungen vorbereitet, die von 0.1 bis 1 % Glyoxal enthalten haben. Das Quellwasser wurde als blinde Probe benutzt.Für die potenziostatische Polarisation wurde das Standard DreiElektroden-System benützt, mit Hilfe von diesem wurde der Korrosionsstrom, das Korrosionspotenzial und die Widerstandsfähig-keit des Materials berechnet.In den vorbereiteten Wasserlösungen mit Glyoxal wurden die Leitfähigkeit, die gesammten gelösten Feststoffe, der Salzgehalt, die Widerstandfähigkeit, pH und das absolute und relative Potenzial bestimmt. Die Konzentrationen von Glyoxal zeigen schon ab 1 % und mehr die beschleunigte Korrosion auf der Oberfläche des austenitischen Edelstahls.

The influence of surface roughness on the pitting potential and the corrosion potential of the DIN W.Nr. 1.4541 and DIN W.Nr 1.4465 stainless steels were examined using electrochemical techniques. Roughness and electrochemical tests were performed on samples with various surface finishing. Electrochemical studies were conducted in an electrochemical cell where steel electrodes were immersed in 0.1 M NaCl and 0.1 M NaCl + 0.1 M Na 2 SO 4 aqueous solutions. We found for both materials when immersed in 0.1 M NaCl aqueous solution lower pitting potential than in 0.1 M NaCl +0.1 M Na 2 SO 4 . The results showed that the electrochemical behaviour of the DIN W.Nr. 1.4465 is better than of DIN W.Nr. 1.4541.Keywords: stainless steels / surface finishing / pitting potential (E pit ) / corrosion potential (E corr ) / Der Einfluss der Oberflächenrauheit auf das Lochfraß-und Korrosionspotenzial der DIN W.Nr. 1.4541 und DIN W.Nr. 1.4465 Edelstähle wurde anhand von elektrochemischen Verfahren untersucht. Rauheits-und elektrochemische Untersuchungen wurden an Proben mit verschiedener Oberflächenveredelungen durchgeführt. Elektrochemische Studien wurden in einer elektrochemischen Zelle durchgeführt, wo Stahlelektroden in 0.1 M NaCl und 0.1 M NaCl + 0.1 M Na 2 SO 4 wässrigen Lösungen eingetaucht wurden. Wir fanden für beide Materialien, dass das Lochfraßpotenzial beim Eintauchen in 0.1 M NaCl wässriger Lösung niedriger ist als in 0.1 M NaCl + 0.1 M Na 2 SO 4 . Die Ergebnisse zeigten, dass das elektrochemische Verhalten von DIN W.Nr. 1.4465 besser ist als von DIN W.Nr. 1.4541.

In this Paper potentiodynamic and Tafel (anodic and cathodic) polarization tests were conducted in order to relate the dependence of surface roughness on the resistance to pitting corrosion (pitting potential) of AISI 316 stainless steel in spring water at 20 8C. Furthermore, uniform corrosion resistance of AISI 316 steel was studied. Tests were performed on seven samples that were polished with emery paper with silicon carbide particles of various grits. Using scanning electron microscope qualitative evaluation of surface roughness was done, and roughness parameter Ra was measured using stylus instrument. Achieved results show that with decreasing mean arithmetic deviation of profile investigated surface significantly increases the resistance to pitting potential, and expands the passivation area of the AISI 316 stainless steel in spring water.

It is well known that measurement uncertainty is a key indicator of the quality of measurement results. We evaluate measurement uncertainty because the measurements are not perfect, for the purpose of unambiguous expression and comparison of measurement results obtained in various calibration and testing laboratories and also in order to compare the measurement results with the manufacturer's specifications or tolerance interval. In the paper, the impact of measurement uncertainty on the acceptance or rejection of a product according to its specification and measurement result is analysed. Decision rule based on simple acceptance and decision rules based on guard bands are described. In order to determine whether specified requirements relating to a product, process or system are fulfilled the different methods for uncertainty evaluation are also discussed.

Conformity assessment is defined as any activity that is undertaken to determine whether a product, system or process meets the relevant standards and performs certain requirements. The decision whether the object of interest is in accordance with a request is based on the measurement results. The quality of the measurement results is described by the measurement uncertainty that is relevant to conformity assessment. The consumer and producer risks are described in this paper, as well as their impact on the conformity assessment and the way in which they can be managed. This paper also describes the impact of measurement uncertainty on the acceptance and rejection of a product according to its specifications.