Tribocorrosion Behavior And Heavy Metal Migration Of Stainless Steeland PTFE Non-stick Cookware

In recent years,with the rapid development of food science and technology as well as the improvement of people’s living standard,the applicability and safety of food contact materials has become the focus of public concern.The cookware made from stainless steel and PTFE-coated stainless steel are widely used in our daily life.However,while selecting kitchenware,most people concern the durability and cost of cookware while ignore the safety in use.In addition,the traditional method applied in safety detection of food contact materials is the static test for harmful substances migration from the soaking solution.Thus,further research should be made to establish a comprehensive evaluation method by combining the mechanical properties of products and harmful substances detected in dynamic experiments.In this thesis,AISI304 stainless steel and PTFE-coated AISI 304 stainless steel（304-PTFE）are selected and their corrosive wear and ion migration behavior are discussed.The experiment draws the following conclusions:（1）AISI 304 stainless steel has similar corrosion-wear mechanism in 3%（volume fraction）acetic acid and 0.3%（5 g/L）citric acid.The total volume loss of stainless steel increases with the increase of applied potential.Correspondingly,the migration amount and rate of Cr,Ni,Mn elements increases in the two solutions.However,because of the high metal complexation capacity of citric acid,the open circuit potential of stainless steel in citric acid solution is higher than that in acetic acid solution.The amount of heavy metals migration and total volume loss of stainless steel is larger in citric acid solution than in acetic acid solution.（2）The tribological properties of 304-PTFE in food simultants are the results of various factors,such as load,time of sliding,the type and concentration of food simulations,etc.Of all the four simulations,304-PTFE shows the maximum friction coefficient of 0.75 in deionized water as well as the minimum of 0.3 in citric acid solution,and get the minimum total volume loss in citric acid solution under the same load.（3）The type of food simulations is the main factor determining the migration of heavy metals in 304-PTFE.The total amount of heavy metal migration in 304-PTFE is tested most in citric acid solution and least in deionized water.On the other hand,maximum amount of migration Cr element are found in citric acid solution,while Ni and Pb in Na₂CO₃ solution.However,minimum amount of migration Mn element are found in deionized water.