Thermal Stability, Corrosion Resistance, And Surface Analysis Of Cu-hf-ti-ni-nb Bulk Metallic Glasses

摘要

Bulk metallic glasses (BMGs) with high thermal stability and good corrosion resistance were synthesized in the (Cu_(0.6)Hf_(0.25)Ti_(0.15))_(100-x-y)Ni_yNb_x system by copper mold casting. The addition of Ni element causes an extension of a supercooled liquid region (ΔT_x = T_x - T_g) from 60 K for Cu_(60)Hf_(25)Ti_(15) to 70 K for (Cu_(0.6)Hf_(0.25)Ti_(0.15))_(95)Ni_5. The simultaneous addition of Ni and Nb to the alloy is effective in improving synergistically the corrosion resistance in 1 N HCl, 3 mass% NaCl, and 1 N H_2SO_4 + 0.01 N NaCl solutions. The highly protective Hf-, Ti-, and Nb-enriched surface film is formed by the rapid initial preferential dissolution of Cu and Ni, which is responsible for the high corrosion resistance of the alloys in the solutions examined.