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Alloy Layers (alloy + layer)

Distribution by Scientific Domains

Polymers and Materials Science	50%

Selected Abstracts

Abscheidung von Palladium und Palladiumlegierungen mit hohen Schichtdicken für die Mikrosystemtechnik

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 2 2007
E. Günther
Palladium and palladium alloys; Heavy deposits are used; Microsystems technology; Internal stress; Graph of current density vs. potential Abstract Die Abscheidung von Metallen und Legierungen in Mikrostrukturen erfordert meist eine Schichtdicke größer als 100 ,m, die der Strukturhöhe entspricht. Für die Nutzung von Edelmetallen in Mikrosystemen ist die Abscheidung von spannungsarmen, rissfreien, porenfreien und duktilen Schichten notwendig. Da die kommerziell abgeschiedenen Edelmetallschichten nur bis etwa 10 ,m qualitätsgerecht abgeschieden werden können, sind geeignete Zusätze und Variation der Abscheidungsbedingungen erforderlich, um mikrosystemtaugliche Elektrolyte zu entwickeln. Charakterisierung der Schichteigenschaften, Parameter der Abscheidungstechnologie und Anwendungsbeispiele werden aufgeführt. Erste Ergebnisse werden vorgestellt und diskutiert. Deposition of Thick Palladium and Palladium Alloy Layers for Microsystems Technology Layers of metals and alloys deposited in microstructures usually require to be thicker than the 100 ,m which is the approximate height of the structure. The deposited form of noble metals used in microsystems must be non-stressed, ductile and free of cracks and pores. As the thickness of layers deposited from commercial noble metal electrolytes will rarely exceed 10 ,m without loss of quality, developing an electrolyte system suitable for microsystems involves finding appropriate additives and deposition parameters. Details are given of deposit characterisation, the parameters of the deposition technology and some practical examples. Initial results are presented and discussed. [source]

Nanostructured Alloy Layers With Magnetic Properties Obtained by the Impulse Plasma Deposition

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Katarzyna Nowakowska-Langier
Abstract The main purpose of our work was to study the growth mechanism during the impulse plasma deposition (IPD) and its influence on the structure and the magnetic properties of the FeTi layers. The deposition processes were conducted by the use of the IPD method in an apparatus equipped with two independent and alternatively working coaxial accelerators of impulse plasma. The properties of the layers allowed to discuss the role of the atom mixing processes for phase structure formation. The comparison between the properties of the FeTi layers and previously studied the FeCu layers were discussed. [source]

AlGaN epitaxial layers grown by HVPE on sapphire substrates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
V. Soukhoveev
Abstract Growth of AlxGa1,xN (x , 0.0-1.0) alloy layers by hydride vapor pahse epitaxy (HVPE) is reported. Crack-free undoped AlGaN layers from 0.1 to 2 ,m thick were grown on 2, SiC and 2,and 4, sapphire substrates. For AlxGa1,xN (x , 0.7-0.8) layers grown on sapphire, high-resolution symmetric/asymmetric X-ray diffraction (XRD) measurements resulted in ,-scan rocking curve widths ranging from 250 to 650 arcsec and from 1400 to 1900 arcsec, for the (00.2) and (10.2) reflections, respectively. Minimum XRD-estimated screw and edge dislocation densities in AlGaN layers grown on sapphire were <6 x 108 cm,2 and <2 x 109 cm,2, respectively. Raman studies revealed that the composition dependences of the phonon modes of HVPE-grown AlxGa1,xN layers are in a good agreement with the one, which have been observed for MOCVD-grown AlxGa1,xN alloys earlier. Grown layers had n-type electrical conductivity for the composition range up to x = 0.4. The layer became highly resistive for higher AlN contents. First results on 40 µm thick crack free AlGaN growth on SiC substrates are reported. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Surface Modification by Compositionally Modulated Multilayered Zn-Fe Alloy Coatings

CHINESE JOURNAL OF CHEMISTRY, Issue 12 2008
V. THANGARAJ
Abstract Compositionally modulated multilayered alloy (CMMA) coatings of Zn-Fe were developed from acid chloride baths by single bath technique. The production and properties of CMMA Zn-Fe coatings were tailored as a function of switching cathode current densities (SCCD's) and thickness of individual layers. Corrosion rates (CR) were measured by electrochemical methods. Corrosion resistances were found to vary with SCCD's and the number of sub layers in the deposit. SCCD's were optimized for production of Zn-Fe CMMA electroplates showing peak performance against corrosion. The formation of discrete Zn-Fe alloy layers having different compositions in the deposits were demonstrated by scanning electron microscopy (SEM). Improvements in the corrosion resistance of multilayered alloys are due to the inherent barrier properties of CMMA coatings as evidenced by electrochemical impedance spectroscopy (EIS). Corrosion resistance afforded by Zn-Fe CMMA coatings are explained in terms of the n-type semiconductor films at the interface, supported by Mott-Schottky's plot. It was observed that the alloy with high w(Fe) on the top showed better corrosion resistance compared to that with the less w(Fe) on top. At optimum SCCD's of 3.0,5.5 A·dm,2, a Zn-Fe CMMA coatings with 600 sub layers showed ca. 45 times better corrosion resistance than conventional Zn-Fe alloy of the same thickness. The deposit showed no red rust even up to 1130 h in salt spray test. [source]