Tantalum coating attracts increasing attention in heat, corrosion and wear resistant applications today because of its high melting point, immunity to chemical attack and high toughness. Recently, tantalum has been considered a desirable candidate to replace electrodeposited (ED) chromium coating which is often used as protective coating against corrosion and wear. However, the wastes associated with ED chromium contain a well-known carcinogen, i.e. hexavalent chromium, which is a hazard to environment. In comparison, thick Ta coating is regarded as a more environmental and beneficial replacement. Tantalum coating is usually obtained by magnetron sputtering. However, tantalum exhibits two distinct crystalline phases. The body-centered cubic α-phase is the common phase in bulk metal and thermodynamically stable. α-Ta with good ductility and excellent mechanical properties is welcomed in most fields. β-Ta is a metastable phase with tetragonal crystalline lattice structure. The properties of β-Ta are not as advantageous as α-Ta because it is hard and brittle. The existence of β-Ta may compromise tantalum coating in adhesion, corrosion and wear resistance, hence, finding appropriate deposition conditions to obtain pure α-phase Ta coating has attracted a lot of interests. In previous work, pure α-phase Ta coating has been deposited by direct current magnetron sputtering when substrates were located in negative glow space. In this work, nitrogen was mixed in sputtering gases to deposit Ta coating with N interstitially dissolved on stainless steel. Effect of N on microstructure, mechanical and tribological performance of Ta coating was studied. Results indicated that when no nitrogen or very low flux of N₂ (l mL/s) were introduced in gas mixtures, α-phase Ta coating with coarse grains grew and revealed strong reflections of (211) and (110) diffraction peaks. When N₂ flow rate reached to 5 mL/s, Ta coating with N interstitially dissolved was obtained and revealed grain refinement and (110) preferred orientation of TaN_0.1 phase. Compared to α-phase Ta coating, N-doped tantalum coatings displayed excellent wear resistance for their high hardness and H ³/E ² ratio (H—hardness, E—elastic modulus). The wear mechanism for α-Ta coating was abrasive wear, while that of N-doped Ta coating switched to adhesive wear.