What are the properties and application characteristics of molybdenum and molybdenum alloys

       Molybdenum is a refractory metal with a melting point of 2630 °C and a recrystallization temperature of about 900 °C. It has high strength at high temperature and good processing performance. It is not only a heat-resistant coating material, but also the only metal material for heat-resistant hydrochloric acid. Molybdenum has a low coefficient of friction and good wear resistance.

    When spraying molybdenum, the molten molybdenum on the surface can dissolve into the metal matrix, and even form a metallurgical bond on the surface of the smooth cut workpiece. The thickness of the bonding layer is about 1 μm, so it is often used as a primer material. Molybdenum can form a good bond with many metals such as ordinary carbon steel, stainless steel, cast iron, aluminum and its alloys.

    In addition, a part of MoS2 impurities will remain in the molybdenum coating, or react with sulfur to form a MoS2 solid lubricating film, so the molybdenum coating can be used as a wear-resistant coating, such as the working spraying of friction surfaces such as piston rings, brake pads, and aluminum alloy cylinders. layer.

   For the spraying of molybdenum, flame wire spraying is mostly used, which is due to the low cost, simple operation and easy automation of the process. Plasma sprayed molybdenum powder has the advantages of dense spray coating and low oxide content, and molybdenum powder can be mixed with other powder materials, which creates favorable conditions for plasma sprayed molybdenum powder.

    The main disadvantage of molybdenum is that it is easy to be oxidized. Its oxide (MoO3) has a low melting point (about 780 degrees Celsius) and is volatile. Therefore, it will be rapidly oxidized and consumed when it is higher than the melting point.