Method of surface preparation of titanium substrates
AssigneeThiokol Corporation
InventorsRussell A. Crook, Larry W. Poulter
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Abstract
A surface preparation process has been developed for titanium and titanium alloy substrates that greatly improves the resulting bond. The process improves bond strength, fracture toughness, durability and failure mode of adhesive bonds. The process also decreases the sensitivity of titanium substrates to processing variables such as humidity, temperature and hence the processing timelines. The process involves treating a titanium or titanium alloy surface with a soluble silicate solution, such as an alkali metal metasilicate, and subsequently treating the surface with a solution of an organofunctional silane. Employing this two step process, bonding to the titanium substrate is improved.
Claims20
A process for preparing a titanium or titanium alloy surface for bonding comprising the steps of:
- treating a titanium or titanium alloy surface with an aqueous solution of a silicate, wherein the silicate in solution has a concentration of at least 0.004 M;
- and
- subsequently treating the surface with a solution of a reactive organofunctional silane, wherein the silane solution is substantially free of a cross-linking agent such that the silane solution treatment does not produce a siloxane coating.
A process for preparing a titanium or titanium alloy surface for bonding comprising the steps of:
- treating a titanium or titanium alloy surface with a solution consisting essentially of an aqueous solution of a soluble metasilicate and a cleaning agent, wherein the metasilicate has a concentration in the range from about 0.004 M to about 0.04 M;
- and
- subsequently treating the surface with a solution of a reactive organofunctional silane containing a plurality of methoxy, ethoxy, or hydride substituent groups, wherein the silane has a concentration in the range from about 0.02 M to about 0.5 M silane.
Dependencies are inferred from the claim text.