| abstract |
Metal coatings of fine grain (average grain size from 1 nm to 1,000 nm) which optionally contain solid particles dispersed therein are described. Fine-grained metal materials are significantly harder and stronger than conventional coatings of the same chemical composition, due to the strengthening of may-Petch, and have low linear thermal expansion coefficients (CTEs). The invention provides the means to match the CTE of the fine-grained metal coating to one of the substrate, to that of the substrate, by adjusting the composition of the alloy and / or, by varying the chemistry and volumetric fraction of the particulates embedded in the coating. Fine-grained metal coatings are particularly suitable for strong and light-weight items, precision molds, sports items, automotive parts and components exposed to the thermal cycle. Low CTEs and the ability to match the CTEs of fine-grained metal coatings with the substrate CTEs, minimize dimensional changes during the thermal cycle and prevent premature failure. |