1. The development of an industrially applicable process of surface strengthening of titanium or its alloys by chemical thermal impregnation methods has not yet progressed sufficiently. 2. Greatest success was achieved in nitriding with pure metered-out nitrogen or nitrogen under vacuum. Nitriding in ammonia has no advantages over nitriding with nitrogen; it is accompanied by simultaneous absorption of hydrogen by the metal. 3. Carburizing can be performed with carbon powder (graphite, lamp black) in vacuum of in argon with metered-out propane or methane additions. This secures only a thin layer of TiC (7.5μm). Absorption of hydrogen developed during decomposition of the hydrocarbons must not be overlooked. 4. In boronizing as well as in carburizing, a good adhesion of the titanium boride layer is found only when it is thin (about 10 μm).