Effect Of Two Processing Methods On The Corrosion Resistance And Mechanical Properties Of Stents Made Of Cobalt-chromium Alloy

Objective: The experiments for two kinds of casting co-cr alloy corrosion process(tea polyphenols soaking in the artificial saliva, casting before heat treatment), measurement and assessment of its corrosion resistance, as well as the processing of co-cr alloy after tensile experiment, and compare two methods of processing with improving the corrosion resistance of actually caused the change of mechanical properties, providing theoretical basis for clinical application.Methods: Soaked the co-cr alloy in 1.25 g/L tea polyphenols in artificial saliva, heat treatment of cobalt chromium alloy long-term immersion in artificial saliva after soaking, always corrosion rate, and the mechanical performance index and surface morphology change. Experimental component A, B two groups, group A was 1.25 g/L tea polyphenols artificial saliva long-term immersion of cobalt chromium alloy, group B for the heat treatment of cobalt chromium alloy long-term immersion in artificial saliva, control group is without any processing cobalt chromium alloy long soak in the artificial saliva. Observed under scanning electron microscopy(sem) of two kinds of processing cobalt chromium alloy surface morphology change. Before and after treatment were compared to two kinds of, cobalt chromium alloy weightlessness corrosion rate and mechanical properties(tensile properties, bending properties and hardness), to study two kinds of processing methods in the change of the corrosion resistance of co-cr alloy at the same time, the influence on its mechanical properties.Results:(1) three sets of specimens soaked after 100 days, weightlessness corrosion rates were 0.0036 + /- 0.0023, 0.0030, 0.0045 0.0030 mm, 0.0025 mm than the control group, compared to A, B two groups the weightlessness corrosion rates are lower, but there was no significant difference(P > 0.05).(2) before the soaking specimens, macroscopic observation, see its surface brightness, polishing scratches, scratches in the same direction. After soaking, the specimen surface were soaked in before dark, still see burnish marks, marks, no visible damage between groups had no significant difference. Under the scanning electron microscopy(sem), before soaking, each specimen surface grinding marks, more uniform, in the same direction. Soak after 100 days, the specimen surface still see scratches, the control group A surface scratch relative disorder, boundary is coarse, uneven surface, have obvious corrosion pit; A, B group of surface see scattered in the corrosion pits, compared with control group, the corrosion is lighter.(3) in accordance with the relevant national standards on the mechanical properties of the detection of co-cr alloy after different treatment, the tensile strength, bending strength and hardness, can be found that the two methods of processing(tea polyphenols soaking in the artificial saliva, casting before heat treatment) in improves the corrosion resistance of co-cr alloy at the same time, the mechanical properties of the alloy had no significant influence.Conclusion: 1,The method of heat treatment is to improve the corrosion resistance of alloy, it not only can improve the corrosion resistance of alloy, the alloy such as tensile performance has improved, but the heat treatment before casting relatively cumbersome; Tea polyphenol is green tea extract, studies have shown that also can improve the corrosion resistance of co-cr alloy casting and had no effect on the mechanical properties of the alloy, for patients with tea habit, its mouth is tea polyphenols ingredient will be saved, continue for a long time, is bound to improve corrosion resistance of alloy. Tea polyphenols, relative to the heat treatment process is relatively simple, does not need to be cumbersome process before casting, but also for improved corrosion resistance, also had no effect on other properties. 2, wear casting co-cr stent patients, suggest appropriate drinking green tea, not only it is good for denture, also have certain benefits to the body, but it is not recommended to drink strong tea.