Carbide

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

The properties and structure of the boron carbide phase

Abstract: The specimens examined were completely characterized within the homogeneity range of the carbide phase (8.8–20.0 at.% C, i.e. B10.4CB4C). An X-ray study of the lattice dimensions together with accurate measurements of the density of the compounds examined allowed us to determine the number n of atoms contained in the unit cell. The value of n varies linearly with the carbon content between B12(CBC)0.666B1.333 (“B10.4C”; n = 15.33 atoms per unit cell) and B12−xCxC¦BxC1−xC) (“B10.4C”; 0

The effects of cryogenic-treated carbide tools on tool wear and surface roughness of turning of Hastelloy C22 based on Taguchi method

Abstract: In this study, Taguchi method has been applied to evaluate the effect of cryogenically treated tools in turning of Hastelloy C22 super alloy on surface roughness. The optimum parameters (cryogenic treatment, cutting speed, and feed rate) of turning were determined by using the Taguchi experimental design method. In Taguchi method, L9 orthogonal array has been used to determine the signal noise (S/N) ratio. Analysis of ANOVA was carried out to identify the significant factors affecting surface roughness. The statistical analysis indicated that feed rate, with a contribution percentage as high as 87.64 %, had the most dominant effect on machining performance, followed by the cryo-treated tools treatment and cutting speed, respectively. The confirmation tests indicated that it is possible to improve surface roughness significantly by using the Taguchi method. Surface roughness was improved by 28.3 and 72.3 % by shallow (CT1) cryogenic treatment and deep cryogenic treatment (CT2) applied on cementite carbide tools (UT). It found that wear resistance of tungsten carbide insert was increased by shallow and deep cryogenic treatments.

Production of Calcium Carbide from Fine Biochars

Abstract: Carbon is the most abundant source of energy and chemicals on the earth. Biomass produced from photon-activated conversion of atmospheric CO2, and biomass fossils such as coal and petroleum are all carbon-rich sources. In around only one century of heavy industrial use of petroleum, this hydrocarbon source has already depleted to a point of a widespread concern over its scarcity in the decades to follow. Biocarbon, also known as biochar, can be readily produced from a vast sustainable supply of lignocellulosic biomass through pyrolysis. It is often in fine form and characterized by low mechanical strength and high activity in comparison to coal-derived chars. The ability to use biochar for the production of chemicals with high energy efficiency will largely alleviate our dependence on shrinking petroleum feedstock. Herein, we show reaction of fine biochars with fine CaO for the production of CaC2, an important starting material for production of many commodity chemicals. The process offers the potential to redirect the carbon conversion pathway. CaC2 is produced by the reaction 3C + CaO + E ! CaC2 + CO, where E 1 is the energy required for the process, about 445.6 kJmol 1 at above 2000 8C. CaC2 can be readily converted into acetylene by treatment with water: CaC2 + 2H2O!C2H2 + Ca(OH)2. Acetylene is an oxygen-free platform chemical for production of chemicals, for example, polyvinylchloride (PVC), vinyl acetate, and 1,4-butanediol. In this carbon conversion process, the main products CaC2 and then C2H2 are readily separated from other components. The current CaC2 production technology dates back to 1892 and has not changed much since then. 5] It uses an electric arc furnace, which is limited only to small-scale operations, typically less than 40 kt CaC2 per year. This process requires granular char and CaO of 5–30 mm in size and with sufficient mechanical strength, such as coal char, to allow unrestricted release of byproduct CO. Because of the low reaction rate resulting from the low surface area and poor contact between the large feed particles, high temperatures (about 2200 8C) and long reaction times (1–2 h) are usually required. These constraints inevitably result in high energy consumption (4000 kWh tCaC2 ), high production cost, and high CO2 emissions in electricity generation. [7] Autothermal heating by combustion of chars has been studied as an alternative process for CaC2 preparation. [8–10]