Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs (copper/graphite/carbon nanotubes) composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanical properties, conductivity properties, friction, and wear performance of the composite were examined. The results indicate that adding a small amount of CNTs can improve comprehensive property of the composites, especially mechanical property. However, excessive CNT, which is easily winding reunion and grain boundary segregation, results in performances degradation.
It has been demonstrated that sterling silver alloy is a widely used material in the jewelry industry. The anti-tarnish property is one of the most important properties of this material. In this work, the effect of yttrium on the corrosion resistance, and tarnish resistance properties of sterling silver alloy were investigated with the use of CIE-LAB uniform color scale, which gained acceptance as an effective way to assess color. To better understand the mechanism of the effect, the distribution of yttrium in the alloy was analyzed by mainly segregating in gaps among dendrite crystals and grain boundary. An increase in yttrium content in sterling silver alloy resulted in a decrease in the amount of eutectic structure. The tarnish and corrosion resistance of sterling silver were improved with yttrium content increase. However, too high yttrium content will lead to poor anti-tarnish properties.
