Cathodic phosphate coating containing nano zinc particles on magnesium alloy

A technology for preparation of a cathodic phosphate coating mainly containing nano metallic zinc particles and phosphate compounds on magnesium alloy was developed.The influence of cathodic current density on the microstructure of the cathodic phosphate coating was investigated.The results show that the crystals of the coating are finer and the microstructures of the outer surface of the coatings are zigzag at the cathodic density of 0.2-0.5 A/dm^2.The content of nano metallic zinc particles in the coating decreases with the increase of the thickness of the coatings and tends to be zero when the coating thickness is 4.14μm.The cathodic phosphate coating was applied to be a transition coating for improving the adhesion between the paints and the magnesium alloys. The formation mechanism of the cathodic phosphate coating was investigated as well.

Effect of thermomechanical treatment on the mechanical and microstructural evolution of a β-type Ti-40.7Zr–24.8Nb alloy

In this study,the microstructural evolution and mechanical properties of a newly developed Ti-40.7Zr-24.8Nb(TZN)alloy after different thermomechanical processes were examined.As-cast TZN alloy plates were solutiontreated at 890℃ for 1 h,after which the thickness of the alloy plates was reduced by cold rolling at reduction ratios of 20%,56%,76%,and 86%.Stress-induced α”formation,{332}<113>β mechanical twinning,and kink band formation were observed in the cold-rolled TZN alloy samples.In the TZN sample after cold rolling at the 86%reduction ratio plus a recrystallization annealing at 890℃ for 1 h,the deformation products of a stressinducedα”phase,{332}<113>β mechanical twinning,and kink bands disappeared,resulting in a fine,equiaxed singleβ phase.The alloy samples exhibited elongation at rupture ranging from 7%to 20%,Young's modulus ranging from 63 to 72 GPa and tensile strength ranging from 753 to 1158 MPa.The TZN alloy sample after cold rolling and recrystallization annealing showed a yield strength of 803 MPa,a tensile strength of 848 MPa,an elongation at rupture of 20%,and an elastic admissible strain of 1.22%,along with the most ductile fractures during tensile testing.

Titanium-niobium pentoxide composites for biomedical applications

The strength of titanium scaffolds with the introduction of high porosity decreases dramatically and may become inadequate for load bearing in biomedical applications.To simultaneously meet the requirements of biocompatibility,low elastic modulus and appropriate strength for orthopedic implant materials,it is highly desirable to develop new biocompatible titanium based materials with enhanced strength.In this study,we developed a niobium pentoxide(Nb2O5)reinforced titanium composite via powder metallurgy for biomedical applications.The strength of the Nb2O5 reinforced titanium composites(Ti-Nb2O5)is significantly higher than that of pure titanium.Cell culture results revealed that the Ti-Nb2O5 composite exhibits excellent biocompatibility and cell adhesion.Human osteoblast-like cells grew and spread healthily on the surface of the Ti-Nb2O5 composite.Our study demonstrated that Nb2O5 reinforced titanium composite is a promising implant material by virtue of its high mechanical strength and excellent biocompatibility.