Study of the viscosity of liquid $\rm Co_{81}(\rm B{,}~\rm Si)_{19}$ alloys

The temperature dependences of the kinematic viscosity of $\mathrm{Co}_{81}\mathrm{B}_x\mathrm{Si}_{19-x}$ melts $(x = 0{,}~3{,}~7{,}~10{,}~13{,}~17{,}~19$ at $\%)$ in the heating and subsequent cooling modes are studied. The temperature dependences of viscosity are monotonic and are accurately described by the exponential Arrhenius equation. The concentration dependences of the viscosity and activation energy of viscous flow are constructed for the quasi-binary $\rm Co_{81}\rm B_{19}$–$\rm Co_{81}\rm Si_{19}$ system. In this system, when silicon atoms are replaced by boron atoms, the melt viscosity changes slightly. The activation energy isotherm of the viscous flow is close to a linear function.