The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This study presents a characterization result on the inhibition layer formed on C-Mn-Cr and C-Mn-Si dual-phase steels after a short time galvanizing. The samples were annealed at 800 ℃ for 60 s in N2-10% H2 atmosphere with a dew point of -30 ℃, and were then galvanized in a bath containing 0.2 %Al. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) was employed for characterization. The TEM electron diffraction shows that only Fe2Al5 intermetallic phase was formed. No orientation relationship between the Fe2Al5 phase and the steel substrate could be identified. Two peaks of Al 2p photoelectrons, one from metallic aluminum and the other from Al 3+ ions, were detected in the inhibition layer, indicating that the layer is in fact a mixture of Fe2Al5 and Al2O3. TEM/EDS analysis verifies the existence of Al2O3 in the boundaries of Fe2Al5 grains. The nucleation of Fe2Al5 and the reduction of the surface oxide probably proceeded concurrently on galvanizing, and the residual oxides prohibited the heteroepitaxial growth of Fe2Al5.

For efficient and economic production of discrete parts with any material, it is always desirable to obtain the final product using one process alone, without secondary operations. This is called “net-shape” manufacturing. Injection molding is perhaps the best net-shape manufacturing process for materials that can be handled by this method. For polymers and some of their composites, injection molding can mass produce high-precision parts with complex geometry at very low cost. In engineering applications, some injection-molded plastic parts of intricate shape with tight tolerance can be snap-fitted together for easy assembly, while others can achieve extremely high quality to meet the optical functional requirements for such parts as optical lenses and information-storage disks.Since the oil crisis in the early 1970s, the use of polymers as an engineering material has been rapidly increasing to improve energy efficiency for both the processes themselves and the final products. Plastics still constitute one of the world's fastest growing industries. Polymeric materials and their composites offer various desirable properties including high strength-to-weight ratio, corrosion resistance, clarity, and others. Among all the polymer-processing methods, injection molding accounts for approximately one-third by weight of all the polymeric materials processed.