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Carbide
About: Carbide is a research topic. Over the lifetime, 36331 publications have been published within this topic receiving 503586 citations.
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17 Sep 2008TL;DR: In this paper, a negative active material for a rechargeable lithium battery and a method of preparing the same, which is composed of crystalline carbon having a dispersed element serving as graphitization catalyst therein, is presented.
Abstract: The present invention relates to a negative active material for a rechargeable lithium battery and a method of preparing the same, said negative active material comprising crystalline carbon having a dispersed element serving as graphitization catalyst therein. Said negative active material for a rechargeable lithium battery is prepared by the steps of adding an element serving as a graphitization catalyst to a carbon precursor; coking the mixture by heat-treating at 300 to 600° C. carbonizing the cokes; and graphitizing the carbide at 2800 to 3000° C.
93 citations
TL;DR: Tungsten carbide nanocrystal modified Pt catalysts have been prepared by an intermittent microwave heating method and show an improved activity for oxygen electroreduction in alkaline media.
93 citations
TL;DR: The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, and show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.
Abstract: A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR). The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (−0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm−2 at −0.8 V vs. Ag/AgCl). Furthermore, FeMo carbide -NG composites show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.
93 citations
TL;DR: In this paper, the performance of PVD-coated high speed steel (HSS) inserts was compared under identical machining conditions and to evaluate causes and phenomena of wear.
Abstract: Coatings produced by physical vapor deposition (PVD) enhance the performance of tools for a broad variety of production processes. In addition to TiN, nowadays (Ti, Al)N and Ti(C,N) coated tools are available. This gives the opportunity to compare the performance of different coatings under identical machining conditions and to evaluate causes and phenomena of wear. TiN, (Ti,Al)N and Ti(C,N) coatings on high speed steel (HSS) show different performances in milling and turning of heat treated steel. The thermal and frictional properties of the coating materials affect the structure, the thickness and the flow of the chips, the contact area on the rake face and the tool life. Model tests show the influence of internal cooling and the thermal conductivity of coated HSS inserts. TiN and (Ti,Zr)N PVD coatings on cemented carbides were examined in interrupted turning and in milling of heat treated steel. Experimental results show a significant influence of typical time-temperature cycles of PVD and chemical vapor deposition (CVD) coating processes on the physical data and on the performance of the substrates. PVD coatings increase tool life, especially towards lower cutting speeds into ranges which cannot be applied with CVD coatings. The reason for this is the superior toughness of the PVD coated carbide. The combination of tough, micrograin carbide and PVD coating even enables broaching of case hardened sliding gears at a cutting speed of 66 m min −1 .
93 citations
01 Jun 1998-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, MC-type carbide formation in MAR-M247 LC superalloy was systematically investigated using directional solidification and quenching methods in sample growth rates between 0.8×10−6 and 15×10 −6 m s−1.
Abstract: MC-type carbide formation in MAR-M247 LC superalloy was systematically investigated using directional solidification and quenching methods in sample growth rates between 0.8×10−6 and 15×10−6 m s−1. The results indicate that carbide growth rate, carbide forming element enrichment and surrounding solid geometry determine carbide morphology and carbide composition. The carbide forming element enrichment and interface energy control carbide nucleation. Heterogeneous carbide nucleation can occur above the alloy liquidus temperature. Carbide forming element enrichment and trapping behavior of the solid–liquid interface control carbide growth, which occurs at inter-secondary γ-dendrite arm positions and the mushy zone bottom which are rich in carbide forming elements. At fast sample growth rates, the solid–liquid interface can trap carbide nuclei in front of it. This trapping tends to occur at the inter-secondary γ-dendrite arm region.
93 citations