MSU Technologies

Brazing Technology for Aluminum Containing Stainless Steel Providing High Electrical Conductivity Joints

Executive Summary

Oxidation resistive ferritic stainless steels are used in applications such as solid oxide fuel cells where corrosion resistance is needed under extreme environmental conditions. These materials are commonly bonded to other metals or ceramics by methods including brazing where the braze joints need to withstand high temperature cycling. In some metal to metal applications, extremely low joint resistivity is also required after brazing. However, this is difficult to maintain when brazing oxidation resistant ferritic stainless steel due to their composition. MSU researchers have recently developed a new brazing technology that provides strong braze joints between aluminum containing ferritic stainless steels and regular ferritic stainless steel while maintaining outstanding electrical conductivity. The technology also provides exceptional braze joints between the stainless steel and ceramics.

Description of the Technology

The technology involves pre applying and sintering a proprietary composition to at least one of the joint surfaces. This modifies the surface energy of the substrate allowing better wetting and flow of the braze material. The pre applied layer is designed so that it can prevent Al₂O₃ formation during joint formation when brazing aluminum containing ferritic stainless steel to regular ferritic stainless steel.

Benefits

High strength braze joints (up to 50 MPa for joints between aluminum-containing stainless steel to non-aluminum-containing stainless steel)
Low contact resistance (down to 2.60×10-5 Ω•cm²)
Excellent durability and stability against delamination and oxidation
Strong braze joints between ceramics and stainless steel