Date of Award

7-11-2003

Degree Name

Master of Science

Department

Mechanical and Aerospace Engineering

First Advisor

Pnina Ari-Gur, D.Sc.

Second Advisor

Paul D. Fleming, Ph.D.

Third Advisor

Daniel Kujawski, Ph.D.

Access Setting

Masters Thesis-Open Access

Abstract

Nickel was electroplated on cold-rolled 2024-T3 aluminum. The coating was done with reinforcement by nanoparticles of y-alumina or silicon carbide. For comparison, nickel-only coatings were done too. Rectangular samples were coated in nickel sulfamate bath with no particles to determine the optimum coating conditions. The optimized parameters were the current density, time of coating, and agitation rate. After coating conditions were established, composite samples were coated using these conditions. The coated layer was characterized by measuring: thickness, residual stresses, and crystallographic preferred orientation. The coated layer was tested by SEM for evaluation of the quality of the coatings. The presence of embedded particles was confirmed using EDS. Residual stresses measurements in the coatings showed that the highest compressive stresses were found in the case of the nickel-only coatings, adding particles to the coating bath tends to shift the stresses into less compressive or even slightly tensile stresses. Thermal stresses were developed in the coated nickel because of the differences in coating temperature and room temperature, and because of the differences between the thermal expansion and contraction between aluminum and nickel it was found that embedded alumina nanoparticles in the coating increased the microhardness of the layer. A preferred orientation of (100) fiber texture was measured, accompanied by a slight (111) component.

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Metallurgy Commons

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