Preparation of TiB2-TiB/Ti gradient composite porous material used for aluminum electrolysis

Abstract

The invention discloses preparation of a TiB2-TiB / Ti gradient composite porous material used for aluminum electrolysis. The composite material reacts with a mixture of borofluoride and titanium fluoride to generate titanium boride and cryolite, and a cathode material with a TiB crystal whisker layer existing between a TiB2 plated layer and matrix titanium is obtained through solid infiltration processing. The bonding strength of a TiB2 deposition layer and a matrix of the cathode material is high. Under the use condition, the TiB2 layer is not prone to falling off from the matrix, and therefore the service life of the cathode material is effectively prolonged, and complete wetting of molten aluminum is achieved through the porous structure of the cathode material. The preparation is simple in method and process, easy to control and low in production cost.

Description

technical field [0001] The invention relates to cathode materials for aluminum electrolysis, in particular to TiB for aluminum electrolysis 2 -Preparation of TiB / Ti gradient composite porous material. Background technique [0002] The current aluminum electrolysis technology has always used carbon material as the cathode material of the aluminum electrolytic cell. Due to the extremely poor wettability between the metal aluminum liquid and the surface of the carbon cathode material, a certain thickness of aluminum liquid must be kept in the current electrolytic cell to avoid the carbon cathode. Electrode reactions caused by exposure of the surface to the electrolyte are unstable. The thickness of the aluminum liquid in the current aluminum electrolytic cell is usually about 20cm. Such a thick aluminum liquid will move under the action of electromagnetic force, which will deform the interface between the aluminum liquid and the electrolyte. The movement of molten aluminum an...

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Problems solved by technology

However, the above-mentioned materials all have more or less the following deficiencies: such as poor wettability with molten aluminum, poor corrosion resistance to cryolite molten salt and molten aluminum, insufficient bonding with the matrix, poor thermal shock resistance or low thermal expansion coefficient. Equal, pending further in-depth research

Since graphite, metal molybdenum or steel are all related to the deposition of TiB 2 There are large differences in thermal expansion coefficient, density, etc., so under high temperature aluminum electrolysis conditions, the deposition of TiB 2 The bonding force between the layer and the substrate will be weakened, TiB 2 The layer is easy to crack and even fall off from the substrate, which directly affects its service life