Powder Metallurgy

Cold Pressing
A powder compaction method involving uniaxial pressure applied to a controlled amount of ceramic or metal powder. The powder is placed in a die between two movable metal rams and compressed under high pressure at room temperature. CP is effectively used for mass production of simple parts and subsequent sintering of the green body might be required.

Cold Isostatic Pressing
CIP is a powder compaction method involving applying pressure from multiple directions through a liquid or gaseous medium surrounding the compacted part. A flexible mold is used to contain the powder and the process is carried out at room temperature. Cold isostatic pressing produces parts with good density uniformity and allows for more complex parts (long thin-walled tubes). Subsequent sintering of the green body might be required.

Hot Isostatic Pressing
HIP is a powder compaction method involving applying pressure from multiple directions using a gas (Nitrogen or Argon) as pressure medium. A rigid container, steel or similar, is used to contain the powder. The process is carried out at increased temperature and pressure. HIP combines pressing and sintering, producing parts with a uniform high strength structure. A combination of CIP, sintering and HIP is also possible to produce more complex parts.

Plasma Spraying
High quality targets are achieved by using plasma spray. An arc is formed between electrodes in a plasma forming gas. The plasma expands through a shaped nozzle and the target material is fed into the plasma torch. At high velocities and plasma temperatures above 10,000 K the molten or semi-molten material is propelled towards a prepared surface. Upon impact the particles quench rapidly and bond with the substrate. Subsequent impacting particles create a coating buildup.

Other Spraying Technologies
High velocity oxy-fuel spray (dense layers, low oxides), flame spray (higher oxides and porosity) and wire arc spray (fast coating rate, little heat transfer to the substrate) are also used to produce unique targets. Similar to the plasma spray process, molten or semi-molten material is propelled towards a prepared surface by expanding process gases. The particles quench rapidly upon impact, bond with the substrate and subsequent impacting particles build-up the coating.

Sintering
Using state-of-the-art atmospheric sintering ovens, Heraeus is further consolidating "green" compact ceramic parts to near theoretical density. Densification occurs when at high temperatures below the melting point the particles diffuse and pores diminish or even close up.

Vacuum Hot Pressing
VHP is a powder compaction method involving uniaxial pressure applied to a controlled amount of powder placed in a die between two rigid rams. VHP is carried out at elevated temperature and under vacuum, producing high purity parts with increased strength and high green density. VHP is used for mass production of simple ceramic and metal parts.