Preparation And Characterization Of Coatings On Titanium Surface By Laser-Cladding

The bio-glass power was prepared by the sol-gel method,and then the biocoating was prepared on titanium surface by laser cladding.The X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FT-IR?,thermal gravimetric and differential scanning calorimeter?TG-DSC?and scanning electron microscopy?SEM?were used to characterize the properties of the bioglass coatings.Two kinds of bio-glass power were designed in this experiment.The main crystal phase of 1# bio-glass power is Na₂CaSi₃O₈ after heat-treatment at 700 ?,while the main crystal phase of 2# bio-glass power is CaSiO3.The maxium bending strength of the 1# bio-glass was obtained after heat-treatment at 950?,while the optimum heattreatment temperature for 2# bio-glass was 600 ?.The bio-glass coating was prepared on titanium surface by electrophoretic deposition.The effect of deposition voltage,deposition time and solid content on the properties of the bio-glass coating was studied.The coating surface was nonuniform and the deposition amount was too small when the deposition voltage was too low.However,higher deposition voltage caused cracks and spalling of the coating.With the increasing of deposition time,deposition weight increased firstly and then decreased.In this paper,the optimum ranges of deposition voltage and deposition time were 10-15 V and 15-20 min,respectively.The deposition rate increased rapidly with the increasing of solids content of the suspension.The experimental results showed that the optimum solids content of the suspension was 0.5 g biological glass powder in 70 g solvent.The bio-glass coating was prepared by laser cladding.The effects of laser process parameters,composition and pretreatment on the morphology and properties of laser cladding coatings were investigated.For pure bioglass powder system,the best process parameters are as follows: the spot diameter of 0.8-1cm,the distance between laser and the titanium sheet of 1.5-1.6cm,the laser scanning speed of 10-20mm/s,the laser output power of 45%-50% and the interval of the laser scanning pattern of 0.2-0.3mm.