| Two different modes of delamination in nano-alumina-titania coatings on steel substrates, which are attributed to the conventional fully-melted (FM) and the bi-modal fully-melted and partially-melted (FM-PM) coating, are discussed. Using simple theoretical models of the coating/substrate interfaces, typical for these coatings, we analyze the profits of the bi-modal FM-PM coatings over the conventional FM coatings in terms of effective specific energy of adhesion, critical strain of delamination, and critical thickness of the coating. It is shown that use of the bi-modal FM-PM coatings can lead to doubling the interface toughness and increasing the critical strain by 50% and the critical thickness by more than 130%. |
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