In our latest online series of blogs, Precision Ceramics Business Director, Geoff Randle, explains the need for a comprehensive website glossary …
The very nature of technical ceramics involves associated materials and processes which can be complicated and fraught with terms that those not involved in the industry might find confusing.
Many people have sought clarification of these and, as a consequence, I set about putting together a glossary of common terms used within the industry. Initially I thought the list would be fairy short but having spoken to several people outside the company, I discovered that even some of the basic terms were unclear and that there was a need to expand my initial plans.
Probably one of the most appropriate terms to explore as an example is Aluminium Nitride. Unlike Alumina (Al2O3), Aluminium Nitride (AlN) has no numbers in its chemical formula which can be confusing and as such is a perfect candidate for the glossary.
I was also asked recently about machinable AlN which seemed a little strange as I had recently written a blog on the difference between machinable and non machinable ceramics but pointing out that reading blogs might be advantage seemed to be a moot point.
Machinable ALN is a compound of ALN and BN (Boron Nitride) and it is classed as Machinable Aluminium Nitride because the material can be machined with standard tooling. it requires no cooking post machining as it is already cooked or sintered. The key point of this is that most technical ceramics when cooked or sintered shrink so a non- machinable ALN would shrink nearly 20% when its sintered and then be so hard that diamond tooling would be required to machine it to a final tolerance.
Machinable ALN is cooked when it is made as a large block and requires no additional cooking after machining so the material will not shrink and can be machined to an accurate size which will not change.
The third key point is that Machinable Aluminium Nitride also has the trade name – Shapal Hi-M Soft, so Machinable Aluminium Nitride, Machinable ALN and Shapal Hi-M Soft are effectively all the same high grade of material. The term Shapal Hi-M Soft, would seem a complex name for the material until you understand how it developed over the last three decades.
In the beginning there was just Shapal, the technical name for a pure ALN which was only machinable with diamond tools. Then as a machinable ALN was required for special purposes, this was designated as Shapal M Soft; ‘M’ for machinable and ‘Soft’ to distinguish it from hard sintered materials. After a further two decades, this was then improved into its current form of Shapal Hi-M Soft, the ‘Hi’ being added to differentiate the material after its upgrade.
The explanation of the difference between ALN and machinable ALN and its evolution would be difficult to follow and therefore it is a good addition to the glossary.
This will be a new growing website tool and as questions are asked, we will add further detail. For those who already understand technical ceramics, this will be of minimum benefit but for those who don’t and occasionally dip into ceramics, I hope that being able to find the difference between Machinable Aluminium Nitride and ALN together with all the other terms we will add in due course will be useful.