Preparation of wettable TiB2-TiB/Ti cathode by electrolytic boronizing for aluminum electrolytic

Abstract

According to the problems of short life and low strength of TiB₂ coating cathode for current technology in aluminium electrolysis industry, this work synthesized TiB₂-TiB/Ti gradient composite with TiB₂ coating and TiB whiskers in metallic Ti matrix by a electrolytic boronizing method based on similar density and thermal expansivity of the three materials. The phase composition and morphology of the cross-section were determined by X-ray diffraction (XRD), scanning electronic microscope (SEM) and X-ray energy dispersive spectrum (EDS). The results show that uniform TiB₂ layer with a thickness of 8-10 μm is continuously coated on the surface while the TiB whisker connected with TiB₂ layer was embedded dispersedly into the matrix. The TiB crystal whisker has a maximum length of about 220 μm. The growth rate of TiB₂ and TiB is enhanced by the strong reduction of B₄C. The novel gradient design of the composite helps to extend life and improve strength of the TiB₂ cathode in aluminium electrolysis.

Keywords

aluminium electrolysis / electrolytic boronizing / titanium diboride / gradient materials

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