Effect Of Two Soaking Methods On Corrosion Resistance And Mechanical Properties Of Co-Cr Alloy

Objective :In this experiment,two kinds of cobalt chromium alloy were treated by immersion corrosion treatment(phytic acid solution immersion and tea polyphenols artificial saliva immersion),to detect the corrosion resistance and comparison,combined with electron microscope and microscope,whether the comparison of two kinds of soaking methods have effects on the mechanical properties of cobalt chromium alloy in improving resistance to corrosion resistance and provide a theoretical basis for future clinical application.Methods :The cobalt chromium alloy was immersed in 1.25g/L of tea polyphenols artificial saliva for 100 days,and soaking in the PH values were 2,4,6 phytic acid solution in the soaking time were 10 min,20min,30 min,40min,marked,and then,the cobalt chromium alloy was treated again immersed in artificial saliva for 100 day.And the surface morphology of two kinds of CO-Cr alloy after immersion treatment were observed under scanning electron microscope and metallurgical microscope,the change of weight loss rate and mechanical properties(tensile properties and bending properties)of cobalt chromium alloy were compared before and after the two treatments,the influence of two kinds of soaking treatment on the corrosion resistance of CO-Cr alloy was studied.Results :(1)Five groups of specimens were soaked for 100 days,the weight loss corrosion rate was 0.0020 + /-0.0017,+ + 0.0006,+ 0.0023 +-0.0006,+ 0.0012,+ 0.00270,+ 0.0020 + 0.0010,compared with the control group,A,B,C,D four groups of weight loss corrosion rate decreased slightly,but there was no significant difference(P > 0.05).(2)Before the specimen was soaked,the surface of the specimen can be seen with the naked eye,and the surface of each specimen was smooth and bright,and the grinding scratches were consistent;under the microscope,the surface of the 5 sets of test pieces can be seen with more uniform and consistent direction.In the control group,the surface scratches of E group were more complicated and rough,and the surface of the surface of the control group was obviously uneven;A,B,C,D four groups can be seen on the surface of the corrosion pits,but after comparison with the control group E found that the number of corrosion pits were less and less corrosion.ABC three group comparison showed that when phytic acid solution PH=6,time is 30 minutes,the lightest corrosion.With the increase of PH of phytic acid solution,the number of corrosion pits on the surface of the alloy is less and less.A,B,C in the three groups can be observed,with the specimen immersed in phytic acid solution in a longer period of time,the number of visible corrosion pits decreased,but when the soaking time was 40 min,and the corrosion pits for 30 min number increased.(3)According to the relevant national standards testing mechanical properties of cobalt chromium alloy soaked,such as tensile strength,bending strength,the comparison before and after the experiment,two kinds of soaking method(phytic acid and tea polyphenols in artificial saliva)can improve the corrosion resistance of CO-Cr alloy,and not to have a significant impact the mechanical properties of alloy.Conclusions :The corrosion resistance of CO-Cr alloy can be improved by the treatment of phytic acid solution and tea polyphenol,and the mechanical property of the alloy is not obvious.The two methods can be used to improve the corrosion resistance of CO-Cr alloy.