Structure of Noncrystalline Co-25 a/o W Electrodeposit

Abstract

Noncrystalline electrodeposits of Co-25 atomic per cent (a/o) W prepared from ammoniacal alkaline tartrate electrolyte were studied by x-ray diffraction. A model for the structure of this alloy was developed. The principal assumptions involved in constructing the model are based mainly on requirements for the electrodeposition. The model requires that the alloy consist of distinct basic structural units in the form of tetrahedra, each composed of three cobalt atoms and one tungsten atom. The dimensions of this structural unit correspond to those of the intermetallic compound Co3W. Certain criteria .govern the bonding of the tetrahedra to form larger aggregates. The scattermg function calculated from the model agrees quite well with the diffraction data. The model also accounts for differences in the composition of amorphous deposits prepared at different current densities. The electrochemical requirements for the formation of this structure by electrodeposition are discussed. The operation of similar processes in the electro-or chemical deposition of other alloys having stoichiometric composition is considered. * Electrochemical Society Active Member. ABSTRACTThe variables affecting the uniformity of sheet resistance for a two-step shallow phosphorus emitter diffusion were examined. The source used was POCla. The uniformity of sheet resistance (and hence surface concentration) was predominantly dependent on the variables during the deposition process.

Iron–tungsten alloys electrodeposited under direct current from citrate–ammonia plating baths

“…That nanocrystalline structure is obtained during alloy electrodeposition because mutually incoherent particles are too small to form a crystalline configuration energetically [23] or because the atoms do not bond together in the arrangement required for achieving a crystalline long-range order [24]. In our opinion, these two mentioned reasons are self-actualizing during the tungsten alloy electrodeposition due to a simultaneously evolution of hydrogen that randomly blocks surface sites where electrocrystallization of the metal takes place.…”

Structural and magnetic properties of amorphous Co-W alloyed nanoparticles

“…Regarding this feature, some authors suggest that amorphous Co-W films consist of tetrahedral units composed of one W and three Co atoms, which arrange in a structure that does not exhibit macroscopic crystal symmetry. 40 Others ascribe this short-range ordering (SRO) in amorphous alloys to the existence of icosahedral and octahedral clusters. 41 Some of these structures are probably being formed in our Co-W NPs.…”

Structure of Amorphous Ni–P Electrodeposits

“…Also, the width of the first peak is still a little too broad. These discrepancies may be ascribed to the small aggregate size used in calculation of the model interference functions(13) (25) pure Ni) instead of 2.61 A, the results were unsatisfactory. About 40 other aggregates which morphology and in deposition modes were generated by the calculation of SPP's and were then tested whether they could reproduce the pronounced second peak.…”