In the present work, high chromium cast irons (HCCIs) with different high carbon ferro-chrome (HCFC) content were cladded on a low carbon steel (LCS). The microstructure and mechanical properties of the bimetals were characterized. The results show that the microstructure of the HCCIs/LCS bimetals is compact, and no defects such as shrinkages and cracks are observed. The volume fraction of carbides increased with the increase of HCFC content. The carbide types of HCCIs are mainly consisting of Cr-rich M7C3 and M23C6, M3C and Mo-rich M2C. The matrix is consisting of martensite near the edges of the carbides and pearlite inside the grains. The hardness and wear resistance of the HCCIs increased with the increasing HCFC content. The HCCIs/LCS bimetals formed good metallurgical bonding, the interfaces are clear and complete. The diffusion of C atoms occurs on the interfaces of the bimetals, and the diffusion direction is from the HCCIs to the LCS, pearlite zones is formed on the LCS side by the interfaces. The thickness of pearlite zones decreased with the increase of HCFC content. Compared with the HCCIs, the HCCIs/LCS bimetals have greatly improved impact toughness, and the impact toughness decreased with the increase of HCFC content.

In the present study, a high chromium cast iron (HCCI) alloyed with Mo (16 wt.% Cr-6 wt.% Mo-2.4 wt.% C) with excellent wear resistance was bonded to a low carbon steel (LCS) by surface liquid-phase sintering. The bimetal was also subjected to a quenching + tempering treatment. The diffusion behavior of the atoms between the HCCI and LCS was analyzed. The bonding strength of the bimetal was investigated before and after heat treatment. The results show that the bimetal had a good bonding quality due to the uphill diffusion of C atoms. A diffusion zone with a width of approximately 37 μm and a troostite structure formed on the HCCI side by the interface. With different bonding times, there was no obvious change in the width of the diffusion zone. The shear strength of the bimetal at all holding times was reduced from a high level after heat treatment and decreased with increasing tempering temperature. The impact toughness of the bimetal substantially increased compared with that of the HCCI. After a quenching treatment, the impact toughness of the bimetal decreased, and the microhardness of the diffusion zone improved. As the tempering temperature increased, the microhardness and impact toughness decreased and increased, respectively.

The hot-dip galvanized coating was produced on the 7075 aluminum alloy plate by immersion in a pure zinc bath at different temperature from 440°C to 470°C for different modification time (between 1 min and 10 min). The hot-dip galvanized of the treated and un-treated samples were investigated by using scanning electron microscopy (SEM) with EDX analysis, X-ray diffraction (XRD), hardness measurements and potentiodynamic polarization curves. There were three layers fabricated on the 7075 substrate surface, specifically, zinc-rich layer, two-phase mixed layer Al-Zn and interdiffusion layer. Moreover, the 7075 aluminum alloy with the hot-dip galvanized coating exhibit higher hardness and better anti-corrosion properties in comparison with the 7075 substrate.

Corrosion performances of superhydrophobic copper stearate/copper oxide thin films on aluminum substrates by a simple on-step electrochemical process.