The dielectric strengths of CuCr25 series alloys are prepared by vacuum induction melting investigated. The experimental results show that the dielectric strength increases slightly with doping with Ni. As the W powders may not be melted and provide crystallization nuclei of Cr phase during solidification

so the morphology of Cr phase is changed from dendrite to nodular grain

meanwhile

the Cr phase is selectively strengthened. Co is also distributed in Cr phase mainly and strengthen Cr particles. When both elements are added simultaneously

the dielectric strength increases further.