vELECTROPLATING POLYMER BASED ADDITIVE MANUFACTURED PARTS FOR ENHANCED STRUCTURAL PERFORMANCE

Additive manufacturing has been adopted in many aerospace and defense applications to reduce weight and buy-to-fly ratios of low-volume high- complexity parts. Polymer-based additive manufacturing processes such as Fused Deposition Modeling (FDM) has enabled aerospace manufactures to improve the structural efficiency of parts through generative design or topology optimization. This level of design freedom did not exist in the past due to limitations associated with traditional manufacturing processes such as subtractive machining. Improvements in the material and the maturation of the FDM process has led to the production of many non-structural flightworthy parts used in aircraft today. Polymer-based additive manufacturing can be further leveraged in aerospace applications with the addition of electroplated coatings that act as reinforcement. While many of the commonly known electroplated coating applications involve enhancing the part appearance, electroplated coatings can also improve the strength, stiffness, and durability of plastic parts. Depending on the use case, the thickness of the metallic plating material (combination of copper and nickel) can be tailored to achieve the desired composite properties (metal and polymer). In this research, the tensile and flexural mechanical properties were assessed for Ultem™ 9085 FDM printed specimens and compared to specimens with metallic coating thicknesses of approximately 75-μm, 150-μm, and 300-μm. Non- destructive inspections using x-ray computed tomography were performed prior to mechanical testing to assess the electroplated coating thickness variation and overall quality.

Effect of Current Density on Microstructure and Corrosion Resistance of Ni–W Alloy Coatings

Ni-W alloy coating was electroplated on the surface of mild steel and the effect of current density on its corrosion behavior was evaluated in this paper. The microstructure of the coatings were scanning electron microscopy (SEM) Polarization techniques have been used to investigate the corrosion behavior in 3.5wt.% NaCl. The results showed that the surface morphology of the coatings is strongly influenced by the deposition current density. And the increased of current densities is benefit for the Ni-W coating from0.5 to 4A/dm2, and the critical value of current densities is 4A/dm2, the corrosion resistance of electroplated coating present better worse when current densities exceeds the critical value or more.

Study on Using EDXRF for the Determination of Gold Coating Thickness

The paper presents a study on the development of an analysis procedure for determining of gold coating thickness using the EDXRF technique. Gold coating thickness was measured by relating the counts under the Au Lα peak to its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thicknesses. The calibration graph shows a straight line for thin coating measurement until 0.9μm. Beyond this point, the relationship was exponential and this may be resulted from the self-absorption effect. Quantitative analysis was then performed on three different samples namely two gold-coated jewelry samples and a phone connector sample. Result from the phone connector analysis seems to agree with the manufacturer’s gold coating value. Results from the analysis of gold-coated jewelry enable to differentiate the two articles as coated by using the gold wash and gold electroplated coating methods.