Abstract:

Dual titanium boride layers consisting of continuous TiB₂  top-layer and TiB whisker sub- layer were formed on the surface of Ti6Al4V alloy using powder-pack boriding technique. An iso-thickness diagram of the whole boride layer was fitted with the data of thickness of the coating, treatment time and process temperature using Sigma Plot10.0 software. Growth kinetics of the titanium boride layer were analyzed by measuring the extent of penetration of  TiB₂ and TiB whisker as a function of boriding time in the range of 5-20 h and boriding temperature in the range of 1000 - 1100 ℃. By the linear regression analysis of growth kinetics of titanium boride layer, the diffusivity K and average diffusion activation energy (Q) of boron atoms in Ti6Al4V alloy were calculated, respectively.

Key words: Boriding, Powder-pack method, Ti6Al4V alloy, Kinetics, Diffusion