A program is described for the development of solid state diffusion bonding technology for production of tantalum alloy T111 honeycomb panels suitable for either hot structural or heat shield applications in aerospace environments. The investigation and selection of appropriate intermediate materials to effect joining at relatively low temperatures and pressures suitable to the panel configurations is discussed. Emphasis was placed on methods suitable for reasonably low-cost processing. Specific manufacturing problem areas encountered, such as forming, welding, and intermediate application, are discussed. Heating, atmosphere control, and pressure application requirements are described and actions taken to satisfy these requirements are reported. A survey of oxidation protective coatings for tantalum alloys is presented with the actual coatings and procedures used in the program being discussed. Structural testing techniques used in evaluating the integrity of the manufactured honeycomb panels are described. Standard analytical procedures employed in determining failure modes and predicted failure stresses are presented.