ISSN:0947-5117    

DOI:10.1002/maco.19950461017

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19950461018

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19950461019

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19950461020

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractDer Beitrag behandelt das Qualitätsmanagement (QM) in Prüflaboratorien. Der Schwerpunkt liegt einerseits bei den technischen Aspekten wie der Kalibrierung, der internen und externen Qualitätskontrolle und der Validierung und andererseits bei einigen Gesichtspunkten des Labormanagements, z.B. der Qualitätsdokumentation, dem Management‐Review und den Qualitätsaudits. Die Notwendigkeit zur Laborakkreditierung im gesetzlich geregelten Bereich und die Vorteile im gesetzlich nicht geregelten Bereich werden betont. Nach einer Erläuterung der Unterschiede zwischen Prüflaborakkreditierung und der Zertifizierung von QM‐Systemen werden einige neuere Entwicklungen auf dem Gebiet der Akkreditierung und des

ISSN:0947-5117    

DOI:10.1002/maco.19950461002

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractThe electrochemical behaviour of a homogeneous binary Al–4wt.%Cu and of a homogeneous binary Al–3wt.%Zn alloy in weakly acid chloride solutions, in O2‐saturated chloride and citrate buffer solution and in Fe2+/Fe3+‐containing citrate buffer solution has been examined using a rotating disc electrode. In weakly acid and in O2‐containing solutions the behaviour of the AlCu and of the AlZn alloy differs from the behaviour of pure Al. H+‐and O2‐reduction at these alloys take place at a much higher rate. Under certain conditions, the reactions are even under transport control. Obviously, this is caused by the preceding selective dissolution of Al. Clusters from residual Cu and Zn, respectively, can pierce the passive layer and act as cathodic sites. In an electrolyte, where the passive layer is not dissolved, the AlZn and the AlCu alloy behave like pure Al. This is shown with the Fe2+/Fe3+redox system in a neutral bu

ISSN:0947-5117    

DOI:10.1002/maco.19950461003

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractSome observations concerning the aims of corrosion rate monitoring, the choice of the electrochemical parameter, the opportunity of optimising the measurement technique and the usefulness of developing specific software for computerised systems are made. The basic concepts for the evaluation of the mass loss of metals or alloys are introduced and some mathematical formulas of the method of successive approximations are given.A short description of the SOFTCOR‐DC‐PHTS code is given, Which concerns its improvements and the most important points and stresses the significant differences between this program and commercial software and the potentialities of the present method.The experimental applications, concerning the behaviours of Armco iron and SA 182 grades F11 and F22 carbon steels in inhibited 5% by weight HCl solutions at 75°C and SA 106 grade B carbon steel in solutions containing 100 gl−1of EDTA at 100°C and different pH values, have demonstrated the existence of a discrepancy between direct and electrochemical determinations of the corrosion rate. The value of the electrochemical determination of the corrosion rate, obtained through potentiostatic measurements with a polarization time of 1 s, was higher than the mean value of the direct evaluation from weight loss data. The present results show that the electrochemical technique cannot reproduce the true behaviour of a corrosion process. However, the SOFTCOR‐DC‐PHTS program is very useful to deal with the problem of monitoring the corrosion rate of metals in acid media and to process experimental data without the intervention of an operator.Finally, it has been experimentally demonstrated that the determination of the polarization resistance depends on the technique adopted for performing polarization m

ISSN:0947-5117    

DOI:10.1002/maco.19950461004

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractThe electrochemical and corrosion behaviour of a nickel base super alloy (C‐263) has been investigated in the deaerated binary and ternary solution mixture of concentrated phosphoric acid, acetic acid, sulphuric acid, nitric acid or water using potentiostatic technique at 35°C. The possibilities of electropolishing of this alloy in these solution mixtures have been also explored. The alloy showed distinct active, passive and transpassive behaviour in the experimental solutions. The alloy remained active and turned passive in the negative potential region. Transpassive dissolution of the alloy is observed and electropolishing is achieved in this region. The best electropolishing is obtained in 50% H3PO4+ 40% CH3COOH + 10% H2SO4. Higher content of water in the electrolytic solution is not useful for electropolishing of the alloy The experimental results also suggest that a current plateau in the transpassive potential region is not a sufficient condition to achieve electropolishi

ISSN:0947-5117    

DOI:10.1002/maco.19950461005

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19950461006

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19950461007

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY