Key words: magnesium alloy; NaCl solution; corrosion

Magnesium alloys are widely used in automotive, aerospace, transportation and other fields due to their low density, high specific strength, large specific modulus, good heat dissipation, good shock absorption and high impact load capacity compared with aluminum alloys. Especially with the light weight and environmental protection needs of the automotive industry in recent years, as well as the continuous advancement of magnesium alloy research and development technology and recycling technology, magnesium alloys are increasingly used in the automotive industry. As we all know, the core technology of automobile competition is to develop high-performance engines, the so-called "the engine is the best in the world."

Magnesium alloys are widely used in automobile engines because they require the engine to be lightweight and high-speed. The working environment of the automobile engine system is relatively complicated, and the temperature variation range is large (-40~150 °C). The requirements for the material properties of the engine are generally high, and it is required to withstand the heat resistance, the flame resistance and the corrosion resistance in different corrosive media.

However, there is still a big gap between the domestic application of magnesium alloy materials as automotive engine materials and the theoretical reasons. The main reason is that the corrosion problem of magnesium alloys has not been overcome. It is of great practical significance to study the corrosion behavior and mechanism of magnesium alloys used in automobile engines for guiding the application of magnesium alloy materials to automobile engines.