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What Factors Affect The Particle Size Of Molybdenum Powder

2018-9-3      View:

The particle size and particle size distribution of molybdenum powder directly affect the process performance of the powder, which has a great influence on the pressing and sintering process of the powder and the performance of the final product. Since different types of molybdenum products have different requirements on the particle size and particle size distribution of molybdenum powder, It is very important to artificially control the particle size and particle size distribution of molybdenum powder. However, it is difficult to obtain the ideal molybdenum powder particle size and artificial control in industrial production.


Molybdenum powder particle size is one of the most widely considered, most extensive and important physical indicators for molybdenum powder preparation or deep processing of molybdenum products. As we all know, the main factors affecting the particle size of molybdenum powder are temperature, loading capacity (or layer thickness), beat (ie time), MoO3 particle size and K content.


In the long-term production practice, it is found that under the same process conditions, the raw material ammonium molybdate has a large particle size and is reduced by using a finer raw material, and the obtained powder has a coarser particle size. By changing the process conditions, the fine particle raw material can obtain coarse-grain molybdenum powder; coarse-grained raw materials can also obtain fine-grained molybdenum powder.


With dry hydrogen, the molybdenum powder is reduced in two steps at a lower temperature. Under suitable process conditions, the molybdenum powder produced by this method has a particle size of about 2 um or less.


Increasing the thickness of the layer will make hydrogen not easily enter the lower part of the layer, and the diffusion of water vapor generated by the reduction will be hindered. In fact, it will increase the partial pressure of water vapor and promote the volatilization of molybdenum powder. The deposition will grow and the particles will become thicker. Even under a large hydrogen flow rate, the gradient of water vapor inside the powder layer cannot be changed. The particle size of the powder at different thicknesses is different. The thicker the layer, the larger the particle size of the molybdenum powder.