Chromium diboride (CrB₂) additions of less than ~10 mol% act as a densification aid and improve the hardness of titanium diboride (TiB₂). Previous research showed that CrB₂ and TiB₂ form a complete solid solution. While CrB₂ improves the densification of TiB₂ and increases the hardness of TiB₂, it also reduces the thermal and electrical conductivities. The goal of the present study is to determine the kinetics of the dissolution of CrB₂ into TiB₂ by using diffusion couples of TiB₂ and (Ti,Cr)B₂. Diffusion couples will be prepared and undergo heat treatments ranging from 1900-2200°C for times ranging from 8-12 hrs. The resulting diffusion interfaces and microstructures will be examined using scanning electron microscopy. Energy dispersive spectroscopy will be used to determine composition profiles of Ti and Cr across the interfaces at the various times and temperatures. The composition profiles will then be used to calculate interdiffusion coefficients and the activation energy of the active diffusion mechanisms. The discussion will focus on the resulting microstructures and diffusion behavior of the Cr within the TiB₂ as a function of temperature.