Electro-contact material based on copper powder clad with Fe – Cu pseudo-alloy

Abstract

By pressing, rolling and sintering, a composite material (CM) based on copper powder clad with Fe-Cu pseudo-alloy (PA) was created for the working layer of two-layer ruptured electrical contacts. Powder of activated carbon (CA) with a surface of 1000 m2/g served as the arc suppression component. Highly dispersed powders of Al2O3, Fe2Al5, and Fe were also used as additional components. Experimental linear dependences of the conductivity and hardness of copper-based composites on the concentration of individual functional additives have been established. With the addition of mixtures of additional components, CMs were obtained for the working layer of the contact with the following characteristics: electrical resistance — 3.2 – 4.5 μOhm·cm, hardness HB — 790 – 1030 MPa. For a given conductivity of a two-layer contact, which is ≥ 75 % of the conductivity of copper, the dependence of the maximum allowable resistivity of theworking layer (ρ) on the ratio of its thickness to the thickness of the copper layer is calculated. The optimal chemical composition of the working layer of the contact has been determined — 97 % Cu + 1 %  CA + 2 % PA, providing high hardness 1030 MPa and electrical resistance 3.2 μOhm·cm. These characteristics allow creating an electrical contact with a ratio of the thickness of the working and copper layer equal to 1:1.