US 7,320,832 B2 · Fine-grained metallic coatings having the coefficient of thermal expansion matched to the one of the substrate

Abstract

Fine-grained (average grain size 1 nm to 1,000 nm) metallic coatings optionally containing solid particulates dispersed therein are disclosed. The fine-grained metallic materials are significantly harder and stronger than conventional coatings of the same chemical composition due to Hall-Petch strengthening and have low linear coefficients of thermal expansion (CTEs). The invention provides means for matching the CTE of the fine-grained metallic coating to the one of the substrate by adjusting the composition of the alloy and/or by varying the chemistry and volume fraction of particulates embedded in the coating. The fine-grained metallic coatings are particularly suited for strong and lightweight articles, precision molds, sporting goods, automotive parts and components exposed to thermal cycling. The low CTEs and the ability to match the CTEs of the fine-grained metallic coatings with the CTEs of the substrate minimize dimensional changes during thermal cycling and prevent premature failure.

Claims21

Dependent claims

An article comprising

(a) a permanent substrate which at room temperature has a coefficient of thermal expansion in the range between −5.0×10−6K−1 and 25×10−6K−1;
(b) a fine grained metallic coating on the permanent substrate, having an average grain size between 2 and 1,000 nm, a thickness between 25 micron and 5 cm and a coefficient of thermal expansion in the range between −5.0×10−6K−1 and 25×10−6K−1;
and
(c) said article exhibiting no delamination and the displacement of the coating relative to the underlying substrate is less than 2% after said article has been exposed to one temperature cycle consisting of exposure to liquid nitrogen for one minute followed by exposure to 90° C. hot water for one minute, or one temperature cycle according to ASTM B553-71 service condition 1, 2, 3 or 4.

1 more element

Dependencies are inferred from the claim text.

Fine-grained metallic coatings having the coefficient of thermal expansion matched to the one of the substrate

Life of this patent

Fine-grained metallic coatings having the coefficient of thermal expansion matched to the one of the substrate

Life of this patent

Abstract

Claims21