The technological importance of metal borides is based on their extreme hardness, high melting points, high conductivity, and chemical inertness and durability. The borohydrides of zirconium and hafnium are shown to be excellent precursors for the deposition of boride thin films, their volatility enabling fast deposition rates to be obtained. The high hardness of the boron-rich, plasma CVD deposited films makes them ideal for applications as wear-protective coatings.