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SMT4-CT98-2238 - A certified reference material for the scratch test - REMAST - Synthesis report
(2002)
Auf Basis einer Literaturstudie werden der Stand und die Perspektiven des Recyclings beschichteter Bauteile vorgestellt. Die Studie ist verfahrens-, branchen- und produktübergreifend angelegt. Die gesetzlichen Rahmenbedingungen werden erläutert, eine Auswahl beschichteter Bauteile und Materialkombinationen bezüglich ihrer Recyclingfähigkeit untersucht und unterschiedlichste Recyclingverfahren diskutiert. Auf die Bedeutung des Recyclings beschichteter Bauteile als spezieller Verbundwerkstoff wird eingegangen.
Although adhesion testing of coatings is of fundamental interest for quality assurance, it is still a challenge regarding reliable quantitative results. Because of the huge variety of coating/ substrate systems in terms of materials and thickness range, adhesion tests display the same variety as coating/substrate systems. Some tests are qualitative, many are quantitative but except for the pull (DIN EN ISO 15870) and pull-off test (DIN EN ISO 4624) adhesion is not measured in terms of force per area.
For optical coatings, the standardized tests according to ISO 9211-4 apply, i.e. abrasion tests (cheese cloth or eraser test) and adhesion tests (tape or cross-hatch test) with different degrees of severity. Instead of the adhesion strength, all these single-sample tests provide only quantitative information on the abrasion or adhesion resistance of a particular coating/ substrate system.
The centrifuge test has manifold advantages. First, it can be easily run as multiple-sample test. Second, adhesion strength is measured in absolute numbers (N/mm2). Third, the centrifuge test requires only a one-sided sample support instead of a two-sided sample clamping as the pull- and pull-off test do. Fourth, it is much easier and faster than many other tests. Fifth, the centrifuge technology additionally enables tests under defined climates or harsh environments. Last but not least, versatile test conditions (alternating loads at various load rates) important to fatigue testing can be easily realized by varying the number of revolutions.
The centrifuge test was applied to the testing of optical coatings on glass and CaF2. It could be shown that there are significant advantages compared to other tests. In particular, the centrifuge test was able to discriminate the adhesion strength for coating/substrate systems until failure which all passed the standardized tests of ISO 9211-4.
Zusammenfassung
Some methods of nano-scale analysis are on the threshold of being a standard method in industry and therefore quality assurance becomes important. But, at the present time, there are deficits in standardisation and validation of these methods. Therefore, we have organised method comparisons and interlaboratory comparisons to overcome these deficits. We report the results of an interlaboratory comparison in step-height determination by atomic force microscopy and the development of a reference material for laterally resolving methods of material analysis.
Neue Produkte und Technologien erfordern oft auch neue Werkstoffe, doch lassen sich die mittlerweile gestellten Anforderungen kaum noch mit einem einzigen realisieren. Deshalb nutzt man häufig unterschiedliche Materialien in Verbunden. Einen bedeutenden Beitrag dazu leisten Oberflächen- und Dünnschichttechniken, die Eigenschaften modifizierter Randschichten beziehungsweise aufgebrachter Beschichtungen mit denen des Grundwerkstoffs kombinieren. Typische Schichtdicken liegen zwischen wenigen Nano- und bis zu einigen Mikrometern (millionstel beziehungsweise tausendstel Millimetern).
Solche Überzüge mit besonderen Eigenschaften wie Glanz, Härte oder chemische Beständigkeit lassen sich auf vielfältige Weise herstellen. Zu den klassischen Verfahren für Beschichtungen gehört etwa die Galvanotechnik, also das im allgemeinen elektrochemische Abscheiden von Metallen zum Korrosionsschutz oder als dekorativer Überzug. Das Verfahren wurde bereits 1840 in Frankreich und England zum Vergolden und Versilbern eingesetzt. Heutzutage versteht man darunter auch rein chemische, also stromlose Methoden der Metallisierung. Es lassen sich damit Legierungen abscheiden und Hartstoff-Partikel für den Verschleißschutz beigeben; auch die Mikroelektronik-Industrie nutzt Weiterentwicklungen der Galvanotechnik in der Chip-Fertigung, um Leiterbahnen und Kontakte aufzubringen.
Um nahezu beliebige Legierungen sowie viele chemische Verbindungen ohne Belastung der Umwelt durch Abfälle der galvanischen Bäder auf Stahl, Leichtmetall, Glas oder auch Kunststoff extrem dünn abzuscheiden, wurden die in den vorstehenden Beiträgen beschriebenen Prozesse der Gasphasenbeschichtung - physical und chemical vapour deposition (PVD und CVD) - entwickelt. Keramische Überzüge, halb so hart wie Diamant, schützen Werkzeuge wie Bohrer, Fräser und Schneiden oder stark beanspruchte Maschinenbauteile wie Lager, Scheiben, Federn und Kolben vor Verschleiß;[...]
Die Festlegung von einheitlicher Terminologie, Schnittstellen sowie Mess- und Prüfverfahren in Normen schafft Vertrauen bei Endnutzern und Investoren und ebnet den Weg für weitere marktfähige Innovationen. Wer die Norm setzt, macht den Markt. In dem sich schnell entwickelnden Gebiet der Nanotechnologien wurden 2005 in ISO (International Organisation for Standardization), IEC (International Electrotechnical Commission) und CEN (Comité Européen de Normalisation) neue Normungsausschüsse etabliert, die jeweils den Titel Nanotechnologies führen. Terminologie und Nomenklatur, Messtechnik, Gesundheit, Sicherheit und Umwelt sowie Materialspezifikationen bilden den Rahmen, aus denen die aktuellen Normungsthemen generiert werden. Deutschland ist aktiv an diesen internationalen Anstrengungen beteiligt, insbesondere an den wirtschaftlich wichtigen Themen Terminologie und den in der öffentlichen Diskussion besonders aufmerksam verfolgten Feldern Umwelt- und Arbeitsschutz.
Globalisation of both science and trade has increased the relevance of the comparability of measurement data whether in research, industry or regulatory contexts. Reference materials (RMs) are essential tools in the quest for comparable and reliable measurement results, a quest which laboratories, worldwide, are tasked with every day. An explicit acknowledgement of the importance of RMs in todays measurement systems is found, for instance, in the laboratory accreditation standards, such as ISO/IEC 17025.
Depth profiles of layer systems consisting of different film materials and having different thicknesses are of great practical importance. Multilayer reference coatings of conducting (Ti/Al) and non-conducting (SiO2/Si3N4) material are analyzed with Auger electron spectroscopy (AES) and glow discharge optical emission spectroscopy (GDOES) depth profiling. Deposition techniques, physical vapor deposition for Ti/Al layers and plasma-enhanced chemical vapor deposition for SiO2/Si3N4 layers, as well as measurement and testing procedures for the determination of layer thickness such as optical and mechanical stylus and spectroscopie ellipsometry are discussed. GDOES depth profiles in direct current (d.c.) and radio frequency (r.f.) mode are related to measurements of crater profiles and compared with line scans and depth profiles performed by AES. It is shown that such multilayer reference systems are appropriate for calibration of depth profiles, i.e. the definition and the evaluation of the depth resolution at the interface, the determination of sputter rates both for d.c.- and r.f.-GDOES and AES, the optimization of the conditions of analysis, and the quantification of analysis itself.
Mechanical properties, i.e. hardness and elastic modulus, of amorphous SiO2 and Si3N4 PE-CVD coatings have been studied for two coating thicknesses (0.1 and 1.0 µm) and two substrate materials (fused silica, i.e. Herasil, and borosilicate glass, i.e., BK7) using low load instrumented indentation. The coating systems are being considered for possible use as reference materials for thin film mechanical property test methods. Single layers of SiO2 and Si3N4 and a multilayer stack consisting of five double layers of SiO2/Si3N4 (individual layer thickness: 0.1 µm) were investigated on both substrate materials. A special plasma pre-treatment of the substrates prior to deposition ensured that coating adhesion exceeded inner film stress for all systems considered. The applied indentation load ranged from 700 down to 0.1 mN and resulted in indentation depths from more than 1 µm to about 15 nm. The influence of coating thickness and the effect of the substrate on the measurement of hardness and elastic modulus of the films are discussed, with emphasis on the effects of indentation depth vs. coating thickness on the observed coating properties. One coatingsubstrate system (1.0 µm Si3N4 on Herasil) out of ten was found to be above a critical threshold for tensile cracking of the coating. In this system, termed overcritical, tensile cracks occurred both prior to, and as a result of, indentation, indicating that Berkovich indentation may also be used to probe residual film stress.
Functionality of optical systems requires optical coatings of
high quality which have to be adapted to the application in
terms of the performance of optical parameters such as
reflectivity (AR, low, defined, high), the substrate material of
interest (polymers, ceramics, and glass), the environmental
conditions (such as temperature or humidity), and the service
conditions (such spectral range and power density). Moreover,
in many cases, additional non-optical requirements have
to be met, including mechanical features such as scratch
resistance, hardness and modulus.
Consequently, thickness and overall uniformity requirements
are steadily increasing. In general, these demands can usually
not be achieved by a single film or coating. Instead, films with
specific design features (such as gradients), layer stacks and
multilayers are a prerequisite for high quality layers and their
reliability. For the development of such layer systems, a
versatile cluster deposition system consisting of three clusters
and a cluster-to-cluster handler has been designed. Besides a
PECVD cluster for DLC coatings, two PVD clusters implement
ion assisted electron beam evaporation and plasmabased
sputter technology. In addition to metallic films, preparation
of oxide and nitride optical coatings (SiO2, TiO2, Ta2O5,
ITO, Al2O3, TiN, AlN) in various process modifications (nonreactive,
partially reactive, full-reactive; rf-, dc-, mf- mode;
PEM control) has been carried out.
Within this paper, the effect of several process parameters on
layer quality (optical constants, density, and uniformity) is
discussed for selected applications examples (AR- and HR
coatings, applications at elevated temperatures and applications
of enhanced mechanical performance).
It has been shown that specific features of ion and plasma
assisted PVD processes, including ion-beam and plasma preand
post-treatment of substrates and layer systems, may
widen the application range and improve functionality features
of given coating/substrate systems.
In the last years, a lot of research work has been performed in the field of surface coatings and thin films technology, often supported by governmental research programs, as i.e. in Germany, the Thin Film Technology and OSTec research programs. But up until now, there is still a lack in transfer of this large amount of knowledge created by research activities on to industrial application and commercialization. To overcome this problem, a new web based information system has been developed (http://www.schichttechnik.net), which in a first step will make the whole content of the German OSTec research program (approx. 180 research reports) of the last 10 years available. In further steps, data from products of coating suppliers and other research programs will be taken into account. The database contains the following sections: definition of the coating system, deposition equipment, deposition processes, application properties, test procedures and test equipment, information about standardization and base information about coating processes etc. It will be possible to search for coatings by material properties and functions of coatings, considering also restriction on the substrate. In addition, searching regarding combination of properties, e.g. for wear-resistant, conductive, decorative coatings etc. will also be possible.
This chapter will focus on those standards and standardization projects which are relevant for nanomaterials. These are mainly terminology documents defining a nanomaterial, documents describing the measurement and characterization of nanomaterials, the specifications and performance assessment of nanomaterials, as well as documents describing how nanomaterials can influence environment, health, and safety.