In our latest online blog, Precision Ceramics Business Director, Geoff Randle, recalls his first memory of HIP and how it has now become an important part of the company’s in-house manufacturing operations.
The other day I watched a piece of news footage from the 1970’s and heard the expression ‘Hip & Happening’ which described the music scene of the time. It brought a smile back, somewhat sadly, as I remember the expression the first time around.
The ‘Hip’ part of the expression reminded me of a number of years back when Precision ceramics invested in a ‘HIP’, not a trendy piece of fashion but a Hot Isostatic Press. This very special piece of equipment reaches 2,000°C but unlike standard furnaces, delivers not only temperature but pressure at the same time – 2,000 bar with this particular piece of equipment.
The combination of temperature and pressure is used to optimise the properties of technical ceramics. Materials that are at the cutting edge of their performance can be further enhanced by Hipping, taking them to new levels of fracture toughness. Imagine a standard yttria zirconia, produced and cooked in a normal furnace with no pressure. This material comes out of the furnace and is ready to be used, the standard workhorse of fracture tough oxide materials. If however you wanted to use this material in the most extreme of environments and you wanted to leave no stone unturned in enhancing the materials properties, then Hipping it and attaining an even better performance would be the route.
Hot Isostatic Pressing heats and squeezes the ceramics, closing any tiny pores or micro cracks in the material so that any initiating crack propagation points are closed. So for a crack to start it requires considerably more energy and the pressure on the material prevents the crystals from growing, keeping the properties of a fine structure.
The HIP process requires a very special press, that has to be tested and certified due to the extreme forces used to create these unique materials We are fortunate to be one of the few companies around the world who haves this in house capability. This not only allows us to treat our existing materials but also to develop new exciting materials such as our Zirconia Ultra Tough, ideal for use at the bottom of oil wells in the aggressive chemical conditions and also used in space where there is no fall back for spare parts.
50 years later, HIP is still happening.