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- Haftfestigkeit (4)
- Klebfestigkeit (3)
- Acoustic levitation (2)
- Mass spectrometry (2)
- Mehr-Proben-Vorbehandeln/Kleben/Prüfen (2)
- 16S amplicons (1)
- ALD-Abscheidungen (1)
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- Adhesives and adhesive tapes (1)
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Die Bestimmung der Haftfestigkeit von Lackierungen, Beschichtungen oder Klebeverbunden ist ein wichtiges Analyseinstrument bei der Beurteilung von entsprechenden Fertigungsabläufen. Unter Verwendung einer neuen Zentrifugentechnologie wurde in einem AiF Forschungsprojekt OKTETT die gesamte Prozesskette Vorbehandlung - Verklebung - Prüfung validiert.
Die Bestimmung der Haftfestigkeit von Lackierungen, Beschichtungen oder Klebungen ist wichtig für die Beurteilung von entsprechenden Fertigungsabläufen. Unter Verwendung einer neuen Zentrifugentechnik wurde jetzt ein neues Mehr-Proben-Konzept zur schnellen Validierung von Klebverbindungen entwickelt.
The multiple-sample approach by means of centrifugal adhesion testing (CAT-technology) allows the determination of bonding strength of adhesive-bonded joints on a statistical basis of up to eight samples. Therefore, it is obvious to ensure the continuous handling and identical processing of an octet of samples within the entire process chain of wet-chemical cleaning, plasma-chemical pre-treatment, bonding of samples, and testing of bonding strength. Within the multiple-sample bonding set-up (MPKV-technology) a defined bonding pressure can be adjusted regardless the actual number of samples. A comparison of single- and multiple-sample approach is made for bonding strength of selected adhesives, double-sided adhesive tapes and different material combinations [stainless steel (V2A) vs. stainless steel, polyamide (PA), or polypropylene (PP)]. It is shown that both technologies improve reliability of results
DNA and locked nucleic acid (LNA) were characterized as single strands, as well as double stranded DNA-DNA duplexes and DNA-LNA hybrids using tandem mass spectrometry with collision-induced dissociation. Additionally, ion mobility spectrometry was carried out on selected species. Oligonucleotide duplexes of different sequences – bearing mismatch positions and abasic sites of complementary DNA 15-mers – were investigated to unravel general trends in their stability in the gas phase. Single stranded LNA oligonucleotides were also investigated with respect to their gas phase behavior and fragmentation upon collision-induced dissociation. In contrast to the collision-induced dissociation of DNA, almost no base loss was observed for LNAs. Here, backbone cleavages were the dominant dissociation pathways. This finding was further underlined by the need for higher activation energies. Base losses from the LNA strand were also absent in fragmentation experiments of the investigated DNA-LNA hybrid duplexes. While DNA-DNA duplexes dissociated easily into single stranded fragments, the high stability of DNA-LNA hybrids resulted in predominant fragmentation of the DNA part rather than the LNA, while base losses were only observed from the DNA single strand of the hybrid.
Three effects have been observed in wet-thermally grown structures under bombardement with energetic 15N ions: (1) Out-diffusion of H from the SiO2/Si system through the surface, (2) Accumulation of H at the SiO2/Si interface, (3) Changes in the optical fingerprint spectra of Ψ and Δ in dependence on λ (wavelength) obtained by ellipsometric measurements.
Adhesion and other mechanical behaviour of coatings is at present routinely tested in industry and research organisations using the scratch test. The test has been the subject of a European Standard prEN 1071-3:2000 established by the European Standards Committee CEN TC184 WG5. A previous European project on the development and validation of test methods for thin hard coatings—FASTE—revealed that uncertainties in the Rockwell C stylus tip shape represent a major source of error for the scratch-test method. Therefore a follow-up project—REMAST—was started to develop and certify a reference material as a quality control tool for the testing and qualification of scratch-test instruments. In addition, a considerable effort was devoted to improve the scratch stylus manufacturing process. This paper presents the results of the REMAST project. During a feasibility study, two candidate materials—titanium nitride (TiN) and diamond-like carbon (DLC) coatings both on high speed steel substrates—were evaluated. Because of the lower sensitivity to styli tip shape variations and higher data scatter observed for the TiN coating, DLC was chosen as the reference material to be certified. One thousand samples were produced, as well as qualified styli to carry out the certification campaign, including homogeneity and stability testing. Nine independent laboratories were involved in the certification exercise, and the data were statistically analysed to obtain the certified critical load values and their uncertainty ranges. A certified reference material BCR-692 is available for verification purposes. This presents three repeatable failure events at certified critical load intervals and can provide a good indication of overall scratch-test instrument performance, including stylus condition and calibration. It is also useful as a diagnostic tool, providing a means of sensitive monitoring of machine and stylus performance over extended periods. Considerable improvement of the quality of scratch styli was achieved by the strict control of all manufacturing steps.
SMT4-CT98-2238 - A certified reference material for the scratch test - REMAST - Synthesis report
(2002)
Aufzählung der wichtigsten wissenschaftlich-technischen und anderer wesentlicher Ergebnisse
• ALD Abscheidungen auf Polymeren (PE, PP, PTFE) unter Atmosphärendruck und im Vakuum mit Ozon als Oxidationsmittel wurden durchgeführt:
- Mit Variation der Schichtdicke
- Mit Variation der Zykluszeit
- Mit und ohne Ozon Vorbehandlung der Oberfläche
• ALD Abscheidungen auf (PE, PP, PTFE) in Vakuum mit O2- und H2-Plasma Vorbehandlung wurden durchgeführt.
- Mit Variation der Schichtdicke
- Mit Variation der Zykluszeit
- Mit und ohne Plasma Vorbehandlung der Oberfläche
• Die ALD Prozesse wurden mit in situ Laserellipsometrie untersucht.
• Die ALD Schichten wurden für die Haftfestigkeit bei der BAM ausgewerte