Composition for treating refractory materials for brazing

Abstract

A coating composition that enables refractory materials such as ceramics to be joined to one another or to metallic components using brazing filler metals. The composition is applied on selected areas of the refractory material to define a target area for brazing. In one embodiment, the coating composition includes (i) a Group IVB transition metal component selected from the group consisting of a Group IVB transition metal, a hydride thereof, and mixtures of the Group IVB metals and / or hydrides thereof, (ii) a binder material, and (iii) a fluid carrier. In disclosed embodiments, the Group IVB transition metal component is titanium, and the binder material is a combination of a hydrocarbon resin and a styrene block copolymer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of copending U.S. patent application Ser. No. 10 / 253,382 filed Sep. 24, 2002, which claims priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60 / 324,857, filed Sep. 25, 2001.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to a composition for treating refractory materials in such a manner as to facilitate bonding of the materials to one another. [0004] 2. Discussion of the Known Art [0005] Non-metallic refractory materials such as ceramics are often used in applications that require such materials to be joined to other ceramics, or to metallic components. In the automotive industry, ceramics are used to form many parts that must be bonded firmly onto metallic support plates such as, e.g., high performance brake pads and linings made from aluminum nitride, aluminum oxide or zirconium oxide. In another example, technical ceramic...

AI Technical Summary

Benefits of technology

[0019] Surface coating of ceramics with the inventive composition may allow more control of active metal concentration for interfacial compound development and, subsequently, joint strength. As a result, active metal depletion can be substantially reduced at ceramic surfaces, and deterioration of the physical properties of a braze filler due to excessive active metal concentrations (e.g., 8% or greater) will also be substantially reduced.

[0025] The drying step (in 1., above) removes the fluid carrier and leaves a coating of the Group IVB transition metal component with the binder on the ceramic, thus facilitating later handling of the coated ceramic when joining the ceramic with another like-coated ceramic or a metallic part. After applying the brazing filler metal and undertaking the brazing step, the binder volatizes and is no longer present. The Group IVB transition metal component of the composition is believed to enhance the strength of the braze joint.

Problems solved by technology

Typically, it is difficult to join ceramic materials to one another or to metallic components.

Because existing brazing formulations do not adequately wet a refractory surface, metallization processes are usually performed on a ceramic prior to joining it to another ceramic or to a metal body.