Influence of the nitriding and TiAlN/TiN coating thickness on the sliding wear behavior of duplex treated AISI H13 steel

AISI H13 die steel substrates were low pressure gas nitrided to different thicknesses and hardness values. Nitrided and non nitrided samples were subsequently coated with bi-layer TiAlN/TiN to two different thicknesses. The hardness was measured across the coating thickness and observed to be higher when a thinner coating was deposited over nitrided substrates. The hardness behavior across relatively thin (3 μm) coatings was not affected by the nitrided surface hardness or thickness of the nitride layer in the range of values examined here (80–150 μm). On the other hand, the hardness behavior of thicker coatings (8um) was affected by the nitrided layer, as the thicker coatings were soft due to their columnar structure. The specific wear rate of the duplex coatings was affected by the coating thickness and hardness distribution across the coating system.