Carbide

About: Carbide is a research topic. Over the lifetime, 36331 publications have been published within this topic receiving 503586 citations.

High-rate electrochemical capacitors based on ordered mesoporous silicon carbide-derived carbon.

Abstract: Microporous carbons, produced by selective etching of metal carbides in a chlorine-containing environment, offer narrow distribution of micropores and one of the highest specific capacitances reported when used in electrical double layer capacitors (EDLC) with organic electrolytes. Previously, the small micropores in these carbons served as an impediment to ion transport and limited the power storage characteristics of EDLC. Here we demonstrate, for the first time, how the preparation and application of templated carbide-derived carbon (CDC) can overcome the present limitations and show the route for dramatic performance enhancement. The ordered mesoporous channels in the produced CDC serve as ion-highways and allow for very fast ionic transport into the bulk of the CDC particles. The enhanced transport led to 85% capacitance retention at current densities up to ∼20 A/g. The ordered mesopores in silicon carbide precursor also allow the produced CDC to exhibit a specific surface area up to 2430 m2/g and a ...

Continuous silicon carbide fiber of high tensile strength

Abstract: Continuous silicon carbide fiber of high-tensile strength (about 350 Kg/mm2) was synthesized by means of the heat-treatment of organosilicon polymer obtained from dodecamethylcyclohexasilane. X-ray analysis and high voltage electron microscopic observations revealed that the obtained continuous fiber is an ultrafine grain structure of β-silicon carbide.

Carbide, nitride and boride materials synthesis and processing

Abstract: Part 1 Introduction: overview safety issues. Non-oxide materials - properties and applications engineering: introduction advanced ceramics - origin, current status, trends: origins of advanced ceramics recent status monolithic ceramics ceramics composites manufacturing applications engineering: the market wear components ceramic armour high temperature applications electrically conductive ceramics corrosion resistant applications automotive applications electronic substrates special applications. Critical powder characteristics: introduction Tungsten carbide: effects of Tungsten/carbon stoichiometry hard metal composition silicon carbide: effect of oxygen sintering developments effect of impurities effect of particle size and method of synthesis silicon nitride: sintering developments effect of particle size effect of impurities effect of synthesis method aluminum nitride: sintering developments effect of oxygen effect of impurities effect of synthesis method summary references. Part 2 Carbothermal reduction synthesis processes: overall process safety issues. Thermochemistry and kinetics: introduction thermochemistry kinetics importance of the gas phase synthesis of carbide and nitride powders references. Acheson process: introduction, history basic silicon carbide process description manufacturing cost factors summary references. Electric arc process: introduction boron carbide manufacturing other non-oxide ceramics references. Tube/pusher/moving bed furnace processes: introduction fundamental physio-chemical considerations system design considerations process scale-up considerations safety considerations conclusions acknowledges nomenclature references. Rotary tube reactor processes: introduction rotary furnace design configurations process considerations operating difficulties applications to non-oxide powder synthesis references. Fluidized bed reactor processes: background application to carbothermal reduction processes references. Part 3 Combustion synthesis processes: overall process safety issues. Thermochemistry and kinetics: principles of combustion synthesis thermodynamics and thermochemistry combustion front structure and stability analysis gasless combustion gas solid combustion synthesis of complex composites and solid solutions nomenclature references. Processes: introduction solid-solid reactions gas-solid reactions summary nomenclature references. Part 4 Gas phase synthesis processes: overall process safety issues references. (Part contents).

A review of the present state of art in hard coatings grown from the vapor phase

Abstract: Hard‐coating materials range from ultrahard materials such as ‘‘diamondlike carbon’’ through refractory compounds to alloys. However, transition‐metal carbides and nitrides have achieved by far the highest level of commercial success. Titanium nitride and titanium carbide are the most studied and used. In this paper a review of the hard coating literature is given and includes in addition to nitrides and carbides also oxides, borides, mixed compounds, metals and alloys, and ‘‘diamondlike’’ carbon coatings. Only coatings grown from the vapor phase are discussed. Some considerations involved in selecting coating/substrate combinations as well as basic concepts of hardness and hardness measurements are also given. For example, it is shown that in order to measure the hardness of the coatings correctly the ratio between the film thickness and the depth of the indentation has to exceed a critical value, which depends on the coating/substrate combination. For TiN on steel, the coating thickness has to be a fact...

M3C (M: Fe, Co, Ni) Nanocrystals Encased in Graphene Nanoribbons: An Active and Stable Bifunctional Electrocatalyst for Oxygen Reduction and Hydrogen Evolution Reactions.

Abstract: Transition metal carbide nanocrystalline M3C (M: Fe, Co, Ni) encapsulated in graphitic shells supported with vertically aligned graphene nanoribbons (VA-GNRs) are synthesized through a hot filament chemical vapor deposition (HF-CVD) method. The process is based on the direct reaction between iron group metals (Fe, Co, Ni) and carbon source, which are facilely get high purity carbide nanocrystals (NCs) and avoid any other impurity at relatively low temperature. The M3C-GNRs exhibit superior enhanced electrocatalystic activity for oxygen reduction reaction (ORR), including low Tafel slope (39, 41, and 45 mV dec–1 for Fe3C-GNRs, Co3C-GNRs, and Ni3C-GNRs, respectively), positive onset potential (∼0.8 V), high electron transfer number (∼4), and long-term stability (no obvious drop after 20 000 s test). The M3C-GNRs catalyst also exhibits remarkable hydrogen evolution reaction (HER) activity with a large cathodic current density of 166.6, 79.6, and 116.4 mA cm–2 at an overpotential of 200 mV, low onset overpote...