Preparation,corrosion And Wear Properties Of Zr-Based Amorphous And Nanocrystalline Coating

Zr-based alloys are typical structural materials served in nuclear reactors and chemical corrosion-resistant equipment,due to their excellent mechanical properties,corrosion resistance,and outstanding nuclear properties.However,the Zr-based alloys performances are failure due to the terrible service environment,lead the potential security risks.Therefore,to improve the properties such as corrosion and wear resistances in metals in particular in Zr-based alloys are required.Zr₆₅Cu₃₅ coating,Zr₇₅Cu₂₅ coating and Zr₇₃Cu₁₆Nb₁₁ coating were deposited on Zirconium substrate by using magnetron sputtering technique.The microstructure and mechanical properties of coatings were tested and analyzed.The wear resistance and wear mechanism of coatings were investigated at room temperature.The electrochemical corrosion properties of coatings in NaCl,H₃BO₃ and LiOH solution have been studied.The denpendence of the corrosion resistance of the coatings on microstructure,microalloying Nb and wettability were analyzed,and the corrosion protection mechanism was discussed.The main conclusions were listed as follows:?1?The coatings with thickness of 1²?m exhibits a dense and homogeneous microstructure without any obvious defects,and shows good adhesion to the Zr substrate.TEM analysis showed that the Zr₆₅Cu₃₅ coating exhibits a full amorphous anture and the Zr₇₅Cu₂₅5 coating is made up of both amorphous and nanocrystalline phases.?2?The tribology results showed that the Zr₇₅Cu₂₅ amorphous/nanocrystalline coating has higher wear resistance and its friction coefficient and the wear rate of the coating are 0.4⁰.5,and 2.3×10^-5mm³N^-1m^-1,respectively.In addition,the essential wear mechanisms of Zr substrate are mainly adhesive wear and abrasive wear;while the major wear mechanism of the Zr₇₅Cu₂₅amorphous/nanocrystalline coating is oxidative wear.?3?Electrochemical test results showed that the Zr₇₅Cu₂₅ amorphous/nanocrystalline coating exhibits a higher electrochemical corrosion resistance than the Zr₆₅Cu₃₅ amorphous coating or the Zr substrate in NaCl,H₃BO₃ and LiOH solutions.Moreover,the Zr₇₃Cu₁₆Nb₁₁ coating exhibits a wider passivation interval than the Zr₇₅Cu₂₅ coating in NaCl solution.