Fabraction Of Cu-based Bulk Metal Glasses And Research On Corrosion

In this dissertation, the alloy with composition of Cu₅₀Zr₄₂Al₈ and Cu₄₇Ti₃₄Zr₁₁Ai₈ were synthesized successfully with water cooling copper crucible-suspend melting method in the condition of the argon protection. The rods of 0 4mm were prepared by copper mould casting. X-ray diffraction (XRD) shows that the Cu₅₀Zr₄₂Al₈ samples is amorphous, the different scanning calorimetry (DSC) shows that the glass transition temperature T_g , the crystallization temperature T_x and the liquidtemperature are 733K , 778K and 1173K ,respectively. The temperature interval of the supercooled liquid region AT is 45K, which means that the alloy has higher glass-forming ability.By comparison with the heated method of the industrial furnace, a vacuum furnace for continuous casting, which was used to synthesize the bulk metallic glass, was designed and manufactured by oneself. The heat method of the furnace is induction by high frequency power and the drawing is downward, the maximal volt is 8KV, the pressure in the furnace is adjusted within the range from 0.0 Pa to 0.16xl0⁶Pa, the rods of 0 4 10mm may be prepared. The process parameter of the furnace was studied by experiment. The rod of the length 8mm and the diameter 4mm was prepared in the condition of the pulling speed was 1.8mm/s, the mould temperature was 1195K, the cooling distance was 9mm and the water flux was 2.6L/min. The X-ray diffraction (XRD) shows the sample is crystal.The corrosion resistance of the bulk metallic glass Cu₅₀Zr₄₂Al₈ and Cu₄₇Ti₃₄Zr₁₁Ai₈ were studied in 3.5% NaCl aqueous solution. The corrosion speed, the microscopy, potentiodynamic polarization experiments and electrochemical impedance spectroscopy shows the corrosion resistance of Cu₄₇Ti₃₄Zr₁₁Ai₈ was better than the former. The element Ti and Ni were the important effect. Added the little Cr and Ni into Cu₅₀Zr₄₂Al₈ glass-forming ability and thermal property of the alloy (Cu₅₀Zr₄₂Al₈)₁00-x(Cr₂Ni)_X(X=0,1,2,3,4) was studied. The corrosion speed and microscopy of the bulk metallic glass Cu₅₀Zr₄₂Al₈ and (Cu₅₀Zr₄₂Al₈)98(Cr₂Ni)₂ were inspected after immerged 120h in 3.5% NaCl aqueous solution and shows the corrosion resistance of the bulk metallicglass CusoZ^Alg in 3.5% NaCl aqueous solution may be improved by the little Cr and Ni.