Cobalt

About: Cobalt is a research topic. Over the lifetime, 69899 publications have been published within this topic receiving 1242058 citations. The topic is also known as: Co & Element 27.

Manufacturing method for semiconductor metalization barrier

Abstract: A semiconductor metalization barrier, and manufacturing method therefor, is provided which is a stack of a cobalt layer and cobalt tungsten layer deposited on a copper bonding pad.

High-defect hydrophilic carbon cuboids anchored with Co/CoO nanoparticles as highly efficient and ultra-stable lithium-ion battery anodes

Abstract: We propose an effective strategy to engineer a unique kind of porous carbon cuboid with tightly anchored cobalt/cobalt oxide nanoparticles (PCC–CoOx) that exhibit outstanding electrochemical performance for many key aspects of lithium-ion battery electrodes. The host carbon cuboid features an ultra-polar surface reflected by its high hydrophilicity and rich surface defects due to high heteroatom doping (N-/O-doping both higher than 10 atom%) as well as hierarchical pore systems. We loaded the porous carbon cuboid with cobalt/cobalt oxide nanoparticles through an impregnation process followed by calcination treatment. The resulting PCC–CoOx anode exhibits superior rate capability (195 mA h g−1 at 20 A g−1) and excellent cycling stability (580 mA h g−1 after 2000 cycles at 1 A g−1 with only 0.0067% capacity loss per cycle). Impressively, even after an ultra-long cycle life exceeding 10000 cycles at 5 A g−1, the battery can recover to 1050 mA h g−1 at 0.1 A g−1, perhaps the best performance demonstrated so far for lithium storage in cobalt oxide-based electrodes. This study provides a new perspective to engineer long-life, high-power metal oxide-based electrodes for lithium-ion batteries through controlling the surface chemistry of carbon host materials.

Effect of Grain Size on the Crystal Structure of Cobalt

Abstract: The paper gives an account of measurements made on the lattice parameter of cobalt when the material contained crystal grains of different sizes as found in fine dust, filings and annealed solid rod. The stable structure of cobalt was found to depend upon the grain size: between room temperature and about 450°c when the grain size is very small, as in cobalt sponge, the stable structure is face-centred cubic; when the grain size is larger, as in a solid rod, the stable structure is close-packed hexagonal; when there is a range of grain size, as in fine filings a mixture of these two structures is observed. At temperatures above 450°c cobalt sponge is still face-centred cubic, and the filings and rod also now show face-centred cubic structure with the same lattice parameter (3.5370kx at 18°c). The lattice constants of the hexagonal close-packed structure at 18°c are: a = 2.5003kx, c/a = 1.6322. Different results were obtained according as the material was maintained and examined at elevated temperature or was quenched from elevated temperature and examined at room temperature. All specimens of cobalt, whatever the grain size, annealed at about 1000°c and quenched showed a mixture of the two structures although with cobalt sponge the amount of the hexagonal structure was very small compared with the amount of the cubic structure. Combining these results with recent results by Newkirk and Geisler (1953) it is possible to present a fairly complete picture of the effects observed, between room temperature and 1220°c, with material examined at elevated temperature and with quenched material examined at room temperature. The main results fit the theory of the imperfect hexagonal structure put forward by Edwards and Lipson (1943). A cubic face-centred structure with lattice parameter (3.5540kx) greater than that of the cubic lattice ordinarily found (3.5370kx) was observed with filings quenched from temperatures between about 600°c and 840°c. It is suggested that the material giving this lattice parameter is in a metastable state. The thermal expansion of cobalt sponge is represented by a smooth curve the equation of which, for temperatures up to 650°c, is the quadratic at = α0(1 + αt + βt2), where a0 = 3.5362 kx; α = 12.297 × 10-6; β = 2.042 × 10-9. It shows no transformation such as is found at about 450°c with material in solid form. No other high-temperature transformation was observed.