Steel oxygen-adsorption corrosion demonstration instrument

Provided is a steel oxygen-adsorption corrosion demonstration instrument. An indicating gauge of a galvanometer is arranged at an upper portion of an erected panel of the demonstration instrument; a U-shaped tube is fixed at a lower portion of the erected panel; a pure iron wire and graphite which are adopted as two poles of a primary battery extend into two ports of the U-shaped tube respectively; and the galvanometer is connected with the two poles of the primary battery through conducting wires. When an experiment is carried out, saturated salt water is injected into the U-shaped tube; a small quantity of a potassium ferricyanide solution is added dropwisely into one end of the U-shaped tube where the iron wire is arranged; a plurality of drips of a phenolphthalein indicator are added dropwisely into one end of the U-shaped tube where the graphite is arranged. When a switch K2 is switched off, and a switch K1 is switched on, deflection of a pointer of the galvanometer can be observed, and therefore, learne