Abstract In this work we investigated the effects of sintering atmospheres of titanium dioxides on the wetting behaviour with molten copper by using the sessile drop method. Nano-powders of titanium dioxides were used to fabricate titania substrates. Experimental results showed that titanium dioxides sintered in different atmospheres exhibited a very pronounced difference in the wetting behaviours with the molten metal. Special attention was paid to the correlation of wetting properties with the non-stoichiometry of titania substrates. It was thus deduced that the contact angle increases and the work of adhesion decreases as the titania substrates become more deficient in oxygen.