HIP diffusion bonding

HIP diffusion bonding is used to create a usually solid state bond between two or more materials (either solid or powder) in contact with each other without adhesive, allowing for higher service temperatures and a stronger metallurgical bond.

Benefits

HIP diffusion bonding allows dissimilar materials to be bonded together without the temperature limitations of adhesives. It forms a metallurgical bond with diffusion occurring on an atomic level. It allows premium materials to be bonded to more economical substrates selectively only where the premium material properties are needed, greatly extending lifetimes of critical components in corrosive and/or erosive environments and in elevated temperature applications.

Applications and materials

HIP diffusion bonding is used to bond hardfacing (wear resistant) and/or corrosion resistant alloys to steel substrates for the paper mill and plastic extrusion industries, among others. It is employed by the electronics industry to attach backing plates for cooling onto sputtering targets. These backing plates typically have high thermal conductivity, e.g. aluminium or copper alloys. Interlayer materials can be included to prevent formation of brittle intermetallics which occur in some material systems, or to bridge differences in coefficients of thermal expansion. HIP diffusion bonding is possible between many material systems.

Process details

HIP is used for bonding in the solid state; to collapse and eliminate internal pores, solidify metal powders or bond materials together. HIP diffusion bonding tailors the HIP process to suit the materials in the system, joining them together during the simultaneous application of heat and pressure. For extrusion barrels, usually metal powders are encapsulated and HIPed to become solid liners bonded to the barrels. For sputtering target backing plates, solid-to-solid bonding is typical. The HIP process requires a hermetic seal around the surfaces to be bonded in order to succeed.

HIP diffusion bonding is well-suited for:

• parts requiring bonding on an inner diameter
• elevated temperature applications
• components with a complex design and/or material system not suited for weld overlay or thermal spray
• bonding materials that are difficult to machine
• allowing use of economical substrates and selective placement of premium material