Morton Schwartz

A Comparison of DC and Pulsed Fe‐Ni Alloy Deposits

The effect of hydrodynamics and temperature on the electrodeposition of Fe-Ni alloys has been investigated with dc, pulse, and pulse-reverse electrodeposition techniques. Strong mass-transfer effects in the co-deposition of Fe on rotating cylindrical cathodes were indicated at high current densities. Many features of the present deposition process are shown to be consistent with the Hessami and Tobias model. A comparison of the polarization behavior of single-metal and alloy deposition clearly demonstrate the lower rate of Ni co-deposition in accord with previous reports of anomalous co-deposition of Fe-Ni alloys. X-ray diffraction studies indicate that the crystalline phases (fcc, bcc, and mixed fcc+bcc) in the electrodeposited alloys depend on alloy composition and deposition conditions

Ferromagnetic micromechanical magnetometer

A novel micromechanical magnetometer has been designed, fabricated, and tested that consists of low-stress electrodeposited hard magnetic alloys and surface micromachined polysilicon structures. The sensor responds to applied magnetic fields without consuming any power and the magnitude of the response is scale independent. By optically measuring their response, these second-generation sensors can be used to detect fields as small as 500 nT and their experimental performance agree well with theoretical predictions.

Pulsed Electrodeposition of Iron‐Nickel Alloys

This paper reports on the effects of dc, pulse, and pulse reverse current waveforms on deposition of Fe-Ni alloys studied in unagitated solutions and with a rotating cylindrical electrode. A nickel sulfamate/ferrous chloride electrolyte system at pH 2 less than 2 A/dm{sup 2}. Pulse reverse plating led to a decrease in anomalous deposition at low current densities. Rotating cylindrical electrodes indicated significant mass transfer effects at high current densities. During pulse reverse plating an increase in anodic pulse magnitude decreased anomalous deposition; pulse frequency had its greatest effect in reducing anomalous deposition between 100 and 300 Hz.

Nanostructured magnetic CoNiP electrodeposits: structure–property relationships

Abstract Magnetic CoNiP thin film alloys were electrodeposited from chloride baths. The effects of solution composition, solution pH and film thickness on the magnetic properties, microstructure and phases of electrodeposited CoNiP films were investigated. Solution pH and NaH 2 PO 2 concentration significantly influenced the magnetic properties of CoNiP deposits. These films when deposited from solutions of pH 2.25, hard magnetic deposits ( H C,⊥ ≈2000 Oe and H C,// ≈1000 Oe) were obtained. X-ray diffraction revealed hcp structure consisting of nanocrystalline grains (∼50 nm) with preferred (002) planes as deposit P content and solution pH increased.

Electrodeposition of Iron Group-Rare Earth Alloys from Aqueous Media

Binary iron group (IG)-rare earth (RE) and ternary IG-RE-B alloys were codeposited from aqueous chloride and sulfamate solutions containing glycine as the complexing agent. The effects of solution composition and deposition conditions on deposit composition, coercivity, and morphology were investigated using dc and pulse current electrodeposition, resulting in nanocrystalline deposits approaching amorphism (grain size, ∼5 nm). Continuing research indicates substantially increased RE deposit contents have been achieved with modifications in solution composition and ratios of IG and RE to glycine with applied current density ≥ 300 mA cm -2 and vigorous agitation; e.g., CoSm deposits containing 15-18 atom % Sm have been obtained. A mechanism for the codeposition of the alloys is proposed. It involves hetero-nuclear glycinato coordination complexes as a result of the zwitterionic characteristics of glycine. The complexes adsorbed on the cathode provide step-wise reduction of the depositing metals with surface adsorbed H atoms and/or direct electron transfer, resulting in alloy deposits.