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Composite Powder (composite + powder)
Selected AbstractsSlip Casting of ZrB2,SiC Composite Aqueous SuspensionsADVANCED ENGINEERING MATERIALS, Issue 3 2010Valentina Medri Slip casting of concentrated aqueous suspensions was set up as forming technique for the production of crucibles from ZrB2,SiC composite powder. The dispersion effectiveness and the effect on the final microstructures of two commercial ammonium polyacrylates (Duramax D3005 and Dolapix PC33) used as dispersants were investigated. The first goal was pursued by evaluating the zeta potential of the powders in water at different concentrations of additives, while the second one was assessed by analyzing the microstructure. Duramax D3005 resulted more effective than Dolapix PC33 in electrostatically stabilize the suspensions. Correspondently, almost homogeneous microstructures and lower final porosity of the sintered crucibles were obtained with Duramax D3005, while ZrB2 layers on the vertical surfaces initially in contact with the plaster molds were observed using Dolapix PC33. Moreover, the use of this latter dispersant did not allow the preparation of thick crucible walls due to the sample rupture during the binders pyrolysis stage. [source] Design and Construction of Insulation Configuration for Ultra-High-Temperature Microwave Processing of CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2003Geng-fu Xu A multilayer insulation configuration suitable for microwave sintering of ceramics up to 2100°C was designed and tested successfully. The configuration is based on porous, granular BN/ZrO2 fiber composite powder for packed beds and spacer cylinders. This insulation allows stable, controlled microwave sintering and can be modified to microwave process materials with different thermal, dielectric properties with improved properties. [source] Untersuchungen zur Herstellung siliziumkarbid-partikelverstärkter Aluminiumpulver durch Hochenergiekugelmahlen.MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 6 2010Fabrication of silicon carbide reinforced aluminium powders by high-energy ball-milling High-energy ball milling; Aluminium matrix composite; AA2017; SiC particle reinforcement; Microstructure Abstract Die Herstellung von Siliziumkarbid-Aluminium-Verbundpulver stellt die erste Stufe der pulvermetallurgischen Herstellungsroute für partikelverstärkte Aluminiumwerkstoffe dar. Der Prozess der Verbundpulverausbildung beim Mahlen in einer Hochenergiekugelmühle und der Einfluss von Prozessparametern werden anhand der Al-Legierung EN AW-2017 mit 10 und 15 Vol.-% Siliziumkarbidteilchen der Kornfraktion <2 ,m untersucht. Die Gefügeentwicklung des Pulvers wird materialografisch charakterisiert. Bestimmte Prozessparameter beeinflussen den Verbundpulverzustand zum Teil gegenläufig, so dass der erreichte Optimierungsstand als Kompromiss anzusehen ist. Lösungsvarianten für eine weitere Verbesserung werden aufgezeigt. The fabrication of aluminium silicon-carbide composite powder is the first step of the powder metallurgical production of particle-reinforced aluminium material. This paper deals with the production of silicon-carbide reinforced aluminium matrix (AA2017) composite powder through an high energy ball milling process by using simoloyer- and planetary high energy mills. The Stages of composite powder formation during the high-energy ball milling process will be shown by means of materialographic studies and by micro hardness. Major factors of influence as well as typical problems are discussed. [source] Entwicklung hochverschleißbeständiger wolframschmelzkarbidbasierter Schichten auf Aluminiumbauteilen durch Plasma-Pulver-Auftragschweißen,MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 7 2007S. Kondapalli Dipl.-Ing. plasma transferred arc welding; wear-resistant coating; aluminium; composite coating; fused tungsten carbide Abstract Durch den Einsatz von Wolframschmelzkarbid können Funktionsflächen von Bauteilen mit stark abrasiven Beanspruchungen wirkungsvoll geschützt werden. Bereits seit vielen Jahren wird Wolframschmelzkarbid eingesetzt, um die Verschleißeigenschaften von Stahl zu verbessern. In diesem Artikel werden Ergebnisse von Untersuchungen zum Verschleißschutz von Aluminiumoberflächen mithilfe des Plasma-Pulver-Auftragschweißens von wolframschmelzkarbidbasierten Schichten vorgestellt. Die Wolframschmelzkarbid-Schichten werden mit zwei Methoden entwickelt, zum einen durch Dispergieren von Wolframschmelzkarbidpartikeln, zum anderen durch eine Kombination aus Dispergieren und Legieren von Verbundpulvern auf Wolframschmelzkarbidbasis. Die Schweißbarkeit der Pulversysteme wird für variierende Auftragschweißparameter und Karbidpartikelanteile untersucht. Im Anschluss erfolgt die Analyse der spezifischen Eigenschaften und der Verschleißbeständigkeit der entwickelten Schichten. Abschließend wird das Anwendungspotenzial am Beispiel von Führungsrollen dargestellt. Development of high wear-resistant FTC-based coatings on aluminium components using plasma transferred arc welding Nowadays, functional surfaces of components can be effectively protected from extreme wear with the help of fused tungsten carbide (FTC) coatings. The wear protection of steel components using FTC has been well known for many years. This paper presents the feasible study of improving the wear resistance of aluminium components with FTC particles using plasma powder arc welding. The FTC coatings are developed with two methods: one is the dispersion of carbide particles in aluminium and the other one is the combination of dispersing and alloying of FTC-based composite powders. In this research, coatings within a thickness range of a few millimeters are developed with varying process parameters and compositions of the filler materials. The developed coating systems are tested with regard to their specific properties and their wear resistance. Finally, their application potential is presented. [source] Preparation and applications of novel cross-linked fluoroalkyl end-capped oligomeric nanocomposites possessing aromatic siloxane segments as core unitsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Yuki Goto Abstract Fluoroalkyl end-capped N,N -dimethylacrylamide oligomer and N -(1,1-dimethyl-3-oxobutyl)acrylamide oligomer were reacted with phenylene- and biphenylene-bridged ethoxysilanes under alkaline conditions to yield cross-linked fluoroalkyl end-capped oligomeric composites possessing aromatic siloxane segments as core units. These isolated fluorinated composite powders were found to be nanometer size-controlled fine particles with a good dispersibility and stability in water and organic solvents. Nitrogen adsorption,desorption isotherms confirmed the presence of micropores in these nanocomposites; the micropore size estimated by the HK method was 0.7,0.8,nm. Interestingly, fluorinated nanocomposites possessing a higher micropore volume ratio were found to exhibit a selective encapsulation ability of fullerene into their composite cores. These fluorinated nanocomposites were also applied to the surface modification of poly(methyl methacrylate) film, resulting in a good oleophobicity imparted by fluorine on the surface. In addition, fluorescence emission was visibly observed only from the modified PMMA film surface treated with fluorinated nanocomposites possessing biphenylene units when irradiated by light. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||