On 2018-08-08 14:48:54
Properties and maintenance of silicon molybdenum rods
a. Silicon-molybdenum rods are extruded and sintered by powder metallurgy. If silicon and molybdenum are mixed uniformly and their particle sizes are normally distributed, then when they heat up, the temperature difference is small, which is beneficial to the formation of equilibrium. Temperature field. The cold and hot ends of the silicon molybdenum rod are welded by high current.
b. The melting point of MoSi2 is 2030 ℃, and the maximum working temperature of the silicon molybdenum rod electric heating body is two types: 1700 ℃ and 1800 ℃.
C. When the silicon molybdenum rod is heated, a dense SiO2 glass film is formed on the surface of the MoSi2 electric heating body. It has a strong resistance to oxidation. Once the protective layer is damaged during operation, it will automatically regenerate the protective film and re- Sealed to prevent further oxidation.
d. The reducing gas will destroy the protective layer of silicon molybdenum. Nevertheless, the silicon molybdenum rod electric heater can still be used in a reducing atmosphere at a temperature not exceeding 1350 ° C. Chlorine and sulfur vapors corrode silicon molybdenum rods severely.
e. The silicon molybdenum rod is hard and brittle, so special care should be taken during loading and unloading.
f. The silicon molybdenum rod should be stored in a dry place to prevent the aluminum-plated tip from being dampened and deteriorated.
g. The connection of the silicon molybdenum rod should be in close contact with the white aluminum head at the cold end of the rod.
h. Since the silicon molybdenum rod is easy to react with oxygen and water vapor in the air at 400-700 ° C, the silicon molybdenum rod will be pulverized, so the silicon molybdenum rod furnace should not be thermostatic at this temperature.
i. The electrical properties of silicon molybdenum rods are that the resistance value increases with the increase of temperature, so the resistance of silicon molybdenum rods is very low at low temperatures, and the current passed at this time is very large. Perform current limiting.
j. The resistance value of the silicon molybdenum rod does not increase with the increase of the use time of the heating element, so the old and new silicon molybdenum rods can be mixed and used.
k. The connection of the silicon molybdenum rod should be in close contact with the white aluminum head at the cold end of the rod to avoid ignition.