Nano violet tungsten oxide powder may be applied for producing window heat insulation film with high transparency. Violet tungsten oxide can also be used in the preparation of nano-WC-Co composite powder by violet tungsten oxide spray drying-direct carbonization method.
The spray conversion method is a relatively mature and advanced method for the preparation of WC-Co composite powder in the world. Spray conversion method, also called thermochemical synthesis method, is a method that dissolves soluble tungsten salt and soluble cobalt salt into water to form a composite solution salt, spray-drying to prepare a precursor powder with uniform chemical composition, and then reduce it in a high temperature fluidized bed, carbonizing to obtain nano WC-Co composite powder. However, the carbon content in the WC-Co composite powder prepared by the spray drying-direct carbonization method is difficult to control due to the large temperature range of the reduction carbonization reaction and the difficulty in precisely controlling the phase.
Therefore, some scholars use ammonium metatungstate, cobalt acetate, potassium dichromate and carbon black as raw materials to prepare WC-Co composite powder by spray drying-direct carbonization. And some scholars use ammonium metatungstate, cobalt acetate, pyrolysis carbon as raw materials, and the WC-Co composite powder is prepared by spray drying-calcination-carbonization method. After that, some scholars have studied the preparation of nano WC-Co composite powder by violet tungsten oxide spray drying-direct carbonization method.
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