Influence Mechanism Of Crystal Orientation On Wear And Corrosion Properties Of Copper

Single crystal copper has good plasticity and conductivity,which is used in the field of integrated circuit and micro nano-manufacturing.In this work,the fretting wear and fretting corrosion wear behaviors of single crystal copper with different orientations were studied in the presence and absence of corrosion medium by means of ball disk reciprocating contact.The electrochemical and immersion corrosion properties of copper with different crystal orientations were studied by electrochemical and immersion corrosion methods.The wear and corrosion mechanisms of copper with different crystal orientations were investigated by means of microscope,SEM and EDS.The research are as shows:(1)When worn under the condition of non-corrosive medium,the average friction coefficient increases with the increase of the load,and decreases with the increase of the speed.Under different loads and speeds,the average friction coefficient of Cu(111)is low.The wear volume is(110)>(100)>(111),and the section damage degree is(110)>(100)>(111).Cu(110)has poor wear resistance,and Cu(111)has relatively light wear and good wear resistance.In dry friction,the wear mechanism is mainly oxidative wear and abrasive wear when the load speed is low;with the increase of the load speed,the wear changes from oxidative wear to adhesive wear;when the load speed is high,it is mainly slight abrasive wear and adhesion Wear;work hardening and grain refinement occur during wear,and friction heat generated by sliding friction helps to form an oxide film and plays a role in reducing friction.The Cu(111)plane is densely packed with atoms and has a high elastic modulus.The critical shear stress of the sliding plane is small and easy to slip.(2)The immersion and electrochemical corrosion experiments show that the smooth corrosion area of Cu(110)surface is small,the passivation film formed by Cu(100)is easy to fall off,and the corrosion of Cu(111)is serious.Following the sequence of(110),(100),(111),the capacitive reactance arc diameter decreases,the charge transfer resistance decreases,the impedance modulus |Z| value in the low frequency region decreases,the corrosion current density increases about 0.93 times,and the corrosion potential is negative.The absolute value of the Tafel slope of the anode curve and the cathode curve decreases.Cu(110)has high surface activity and is closely packed.According to the atomic electronic state density and the quantum mechanics viewpoint of bonding,the order of surface energy and easy activation during oxidation of copper with different orientations is(110)>(100)>(111),and the crystal orientation and density of atoms determine its corresponding crystal plane atoms Corrosion of the structure,so the corrosion resistance of single crystal copper is(110)>(100)>(111).(3)When worn under the corrosion medium of NaCl solution,the friction coefficient of copper with different orientations is small,the wear volume and morphology are slight,and the surface is rough.As the load and speed increase,the corrosion and wear are serious,but when it increases to a certain value,the situation is reduced.Average friction coefficient(100)>(111)>(110),corrosion wear(110)>(111)>(100).Under different loads and speeds,the wear volume of Cu(100)is small,and the surface activity of Cu(100)is relatively weak,and it is not easy to react.The copper surface undergoes corrosion and oxidation,adhesion and abrasive wear during corrosive wear.At the same time of corrosion,the corrosive medium plays a role of cooling and heat dissipation,forming an oxide film,reducing adhesion and abrasive wear,and achieving the effect of reducing friction and friction.