Hot isostatic pressing

Hot isostatic pressing (HIP) is a manufacturing process, used to reduce the porosity of metals and increase the density of many ceramic materials.

Nickel, stainless or mild steel, or other metals can be chosen depending on the desired redox conditions.

When castings are treated with HIP, the simultaneous application of heat and pressure eliminates internal voids and microporosity through a combination of plastic deformation, creep, and diffusion bonding; this process improves fatigue resistance of the component.

Hot isostatic pressing is thus also used as part of a sintering (powder metallurgy) process and for fabrication of metal matrix composites,[2] often being used for postprocessing in additive manufacturing.

ANSTO (Australian Nuclear Science and Technology Organisation) is using HIP as part of a process to immobilize waste radionuclides from molybdenum-99 production.