Silicon molybdenum bar

Molybdenum disilicide MoSi2 heating element is mainly to silicon and molybdenum powder as raw material, made of powder metallurgy method by squeezing, sintering, referred to as silicon molybdenum rod. This element can be used in the oxidation atmosphere of 1650 degrees Celsius, is the most used in the industry in the oxidation of the temperature of the heating element.

The shape of silicon molybdenum rod is mainly U - shaped, W - shaped and O - shaped three, which is because of the high temperature of the silicon molybdenum bar at high temperature, so as to avoid the deformation under the self weight and to overcome the high temperature line expansion. With the handle shaped silicon carbide, the cold end bold, to increase the sectional area, reduce resistance.

 

The silicon molybdenum rod is heated to above 1200 degrees C in oxidizing atmosphere and the reaction is as follows:

2MoSi2 + 7O2, 2MoO3 = +4SiO2

MoO3 volatile, SiO2 is attached to the surface of the components to generate a dense quartz glass film, to protect the substrate is no longer oxidation. Therefore, silicon molybdenum rods of oxidation resistance is very good, in oxidizing atmosphere, the highest use temperature up to 1700 DEG C (lower than the melting point of quartz 1713 DEG C). Such as mechanical or chemical damage and damage to the Si02 film, in the use of the process will automatically again.

The performance of silicon molybdenum rod is similar to that of metal ceramic material, which is hard and brittle at room temperature, low impact strength, good bending resistance and good tensile strength, and plastic deformation can occur at more than 1350 degrees, and the elongation is about 5%. The cold and hot sudden change is good, the recovery of brittleness after cooling. The resistivity of silicon molybdenum rod is small, and its resistance temperature characteristic is similar to that of metal, which is the positive temperature characteristic, from room temperature to high temperature, the resistivity increases quickly with the temperature, so it has the advantage of automatically preventing temperature rise too fast.

Silicon molybdenum bar is especially suitable for work in air