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This paper presents, chemistry, test data and processing procedures on a non toxic and environmentally friendly chrome-free conversion coating alternative with the same level of adhesion and secondary corrosion resistance as that found in chrome containing conversion coating systems. Test data from military and independent sources will be presented on secondary coating adhesion, electrical conductivity, filiform and neutral salt-spray corrosion resistance as compared to chromate based systems .on magnesium, aluminum and zinc and their respective alloys. The European “RoSH” initiative will not allow for the presence of any hexavalent chromium on imported electrical components as of July first of 2006. Trivalent chromium based systems generate hexavalent chromium due to the oxidation of the trivalent chromium and as such will not be allowed.

In a 2-year program sponsored by SJAC, an aqueous electroplating process using alkaline Zn-Ni with trivalent chromium post treatment is under evaluation for high strength steel for aircraft application as an alternative to cadmium. Commercial Zn-15%Ni rack/barrel plating solutions are basis for plating aircraft parts or fasteners. Brightener was reduced from the original formula to form porous plating that enables bake-out of hydrogen to avoid hydrogen embrittlement condition. Properties of the deposit, such as appearance, adhesion, un-scribed corrosion resistance, and galvanic corrosion resistance in contact with Al alloy, were evaluated. Coefficient of friction was compared with Cd plating by torque-tension measurements. Evaluation of the plating for scribed corrosion resistance, primer adhesion, etc. will continue in FY2007.

This specification covers a zinc alloy in the form of die castings.

This specification covers the engineering requirements for electrodepositton of zinc and the properties of the deposit.

Over the past two decades, various models of “worst case” solar energetic particle event (SPE) spectra have been proposed in order to place an upper bound on the likely doses to critical body organs of astronauts on missions outside Earth’s geomagnetic field. In this work, direct comparisons of organ dose estimates for various models of “worst case” SPE spectra are made by using the same transport code (BRYNTRN) and the same human geometry model (Computerized Anatomical Man). The calculations are made assuming nominal thicknesses of spacecraft aluminum shielding. Discussions of possible acute exposure responses from these exposures are presented.

This specification covers one type of cushion tread (semi-pneumatic) wheels for use on mobile ground support equipment.

Co+Cr2O3 is a composite coating of a cobalt matrix with 30 percent by volume embedded Cr2O3. The coating can be applied by plating using a suspension of Cr2O3 in a cobalt electrolyte. The mechanical properties of this coating are discussed. The main attribute is the excellent wear resistance of the coating especially in the temperature range of 300 to 700°C. Adhesive wear of unplated counterparts is reduced by the same amount. In contrast to nickel the fatigue strength of Co+Cr2O3 coated Waspaloy was shown to be not influenced, when heat treated at 400°C for 16 hours. Plated engine parts demonstrate the usefulness of the Co+Cr2O3 composite coatings for wear protection.

Magnesium and its alloys are promising engineering materials with broad potential applications in the automotive, aerospace, and biomedical fields. These materials are prized for their lightweight properties, impressive specific strength, and biocompatibility. However, their practical use is often hindered by their low wear and corrosion resistance. Despite their excellent mechanical properties, the high strength-to-weight ratio of magnesium alloys necessitates surface protection for many applications. In this particular study, we employed the plasma spraying technique to enhance the low corrosion resistance of the AZ91D magnesium alloy. We conducted a wear analysis on nine coated samples, each with a thickness of 6mm, to assess their tribological performance. To evaluate the surface morphology and microstructure of the dual-phase treated samples, we employed scanning electron microscopy (SEM) and X-ray diffraction (XRD).

This specification covers plain helical lock washers fabricated from heat treated carbon steel.