A high-speed corrosion-resistant rotating cylinder electrode test cell system for ex situ monitoring of the corrosion rate of a metal material, said metal material being formed as a cylindrical working electrode, comprising: an electrochemical/permeation cell body (12; 112) and a rotatable system shaft, said electrochemical/permeation cell body being in the form of a heat and chemical resistant tube extending above a base and a top disposed on the cell body opposite the base, said cell body configured to retain a fluid whose corrosive effect on the working electrode is to be monitored; a counter electrode mounted within said cell for introducing an electrical current into the fluid; a reference electrode mounted within said cell and having a fixed potential over time; a device for measuring an open circuit potential of said cylindrical working electrode with respect to said reference electrode; and said rotatable system shaft having an upper portion, characterized by said base having an aperture formed therethrough, the surface of the base surrounding the aperture forming a depression at a position around the working electrode; said system shaft being rotatable by a magnetic drive positioned below said base of the cell body and operably connected to an electric motor, said magnetic drive including a magnetic coupler having a head that extends through said aperture which functions as an electrical contact for the cylindrical working electrode, the system shaft being directly connected to said magnetic coupler, and said working electrode being mounted on said upper portion of said system shaft and positioned within said cell body for rotation, the working electrode projecting upwardly from said base to a position that, in operation, lies below the surface of a corrosive fluid placed in the cell body, and the working electrode terminating in a corrosion-resistant top cap with an upper surface in the shape of a cone. an electrochemical/permeation cell body (12; 112) and a rotatable system shaft, said electrochemical/permeation cell body being in the form of a heat and chemical resistant tube extending above a base and a top disposed on the cell body opposite the base, said cell body configured to retain a fluid whose corrosive effect on the working electrode is to be monitored; a counter electrode mounted within said cell for introducing an electrical current into the fluid; a reference electrode mounted within said cell and having a fixed potential over time; a device for measuring an open circuit potential of said cylindrical working electrode with respect to said reference electrode; and said rotatable system shaft having an upper portion, characterized by said base having an aperture formed therethrough, the surface of the base surrounding the aperture forming a depression at a position around the working electrode; said system shaft being rotatable by a magnetic drive positioned below said base of the cell body and operably connected to an electric motor, said magnetic drive including a magnetic coupler having a head that extends through said aperture which functions as an electrical contact for the cylindrical working electrode, the system shaft being directly connected to said magnetic coupler, and said working electrode being mounted on said upper portion of said system shaft and positioned within said cell body for rotation, the working electrode projecting upwardly from said base to a position that, in operation, lies below the surface of a corrosive fluid placed in the cell body, and the working electrode terminating in a corrosion-resistant top cap with an upper surface in the shape of a cone.