The effects of Co addition on the hardness,electrical conductivity and softening temperature of Cu-3. 0Ni-0. 75 Si alloy were studied. The changing regularity of electrical conductivity,hardness and tensile strength of Cu-3. 0Ni-0. 75Si-x Co alloy with temperature at high operating temperatures was investigated,and the alloy tensile fracture morphology was also analyzed by scanning electron microscope( SEM). The results showed that with the contents of Co increasing,the electrical conductivity of Cu-3. 0Ni-...