Study On Plasma OxidationTechnology Of Implants Based On Spectral Diagnosis

In this paper,the surface modification of implants was formed by DC glow discharge,and the variation of particle type,spectral intensity,electron excitation temperature and electron density in glow discharge Ar/O plasma was analyzed by plasmon emission spectroscopy.This paper explores the influence of plasma state on the hydrophilicity,composition and phase of implant surface,explores the super-hydrophilic mechanism and corrosion resistance of plasma oxidation surface.During the discharge of Ar/O system,the changes of different particles were traced by spectroscopy.The changes of electron excitation temperature and electron density during Ar/O discharge were calculated by Bozeman curve method and Shaha-Boltzmann equation.The results show that with the increase of oxygen content,the electron excitation temperature and electron density of the plasma first stabilize and decrease after the oxygen ratio exceeds 50%,and the metastable oxygen atoms and oxygen ions tend to be stable.This indicates that there is a threshold for the effect of oxygen content on the Ar/O discharge system,which has the combined effect of the ionization of Ar and the electronegativity of O.As the bias voltage increases,the atomic,ion content,electron excitation temperature and density first rise,tend to be stable after greater than 700V.The higher the gas flow is,the higher the concentration of atoms and ions will be.However,the electron excitation temperature and electron density will decrease.The excessive gas flow will lead to the separation of overlapping negative light regions,and the center particle density will shift to both sides.The increase in oxygen content facilitates an increase in plasma uniformity in squirrel cage discharges because metastable oxygen atoms move toward the center due to electronegativity.In the Ar/O mixed gas discharge,when the oxygen ratio exceeds 65%,the oxygen content of the oxidized surface tends to be stable.In the state where the oxygen content is low,the oxygen content of the surface oxide layer is lowered due to etching and bombardment of argon ions.In addition,in the case where a large amount of oxygen is incorporated,both of the plasma electron excitation temperature,electron density and particle energy are lowered,the ionization also is weakened.The TiO2 of the surface oxide layer is transformed to Ti2O3 to form a TiO2-x oxide layer.This results in the formation of a doping level in the oxide layer forming a large amount of Ti3+and Ovac from the doped structure,so that the oxide layer produces photocatalytic hydrophilic properties under the action of visible light.When the plasma electron excitation temperature and electron density are similar as well as the oxygen content is low,the rutile phase TiO2 formed on the surface is mainly caused by the de-excitation of Ar in the plasma.When the oxygen content is high,by the above action and the oxidation of a large number of oxygen atoms and oxygen ions,more rutile phase TiO2 is formed on the oxidized surface.The ion precipitation test of the oxidized surface in pure water,NaCI solution and NaOH solution showed that the oxidized surface also reduced the surface corrosion resistance while obtaining high activity.