Silicon nitride is one of the most advanced ceramic materials currently manufactured, providing outstanding hardness levels that are rarely matched by conventionally-manufactured components. Most silicon nitride products are electrically insulating, which provides certain industrial benefits for mechanical applications – but it can present difficulties when it comes to machining the material. Material profiling of ultra-hard insulators can result in a significant loss to its desirable properties, and commonly depends upon expensive procedures such as diamond grinding. Meanwhile, electrically conductive materials can be efficiently profiled through electro-discharge machining (EDM) with no loss to material hardness.
EDM is an advantageous process for multiple reasons. It is a no-contact machining process and as such applies no physical force to a material’s substrate. Instead, the EDM process involves creating a high temperature electric spark with an electrode that precisely melts localized conductive materials. These temperatures can routinely exceed 8000°C. This erosive process is controlled by submerging machined materials in dielectric liquids, which can both cool the material and rinse eroded particles.
Read More: The Electrical Properties of Si3N4
This ingenious principle is ideal for profiling high-hardness materials into complex shapes without risk of heat distortion, surface warping, or reduced mechanical properties. The advantages offered over invasive machining processes made forming an electrically conductive silicon nitride essential.
Syalon 501: Electrically Conductive Silicon Nitride
Syalon 501 is a beta-phase silicon nitride that was developed to take advantage of the machining processes available exclusively to electrically conductive high hardness materials such as tungsten carbide (WC). It exhibits outstanding thermal resistance properties up to 700°C and a hardness value (HRA) of 90.5.
Syalon 101 displays improved mechanical values over Syalon 501, but the increased component design complexity enabled by EDM alone makes the latter a triumph of engineering. In the absence of large scale lithium-additive manufacturing processes, EDM profiling of electrically conductive silicon nitride is the method of choice for designing and manufacturing the most complicated components from refractory ceramics with repeatable results. It is possible to manufacture bespoke extrusion die profiles for wear industries, and unique molds for metal and plastic forming applications with previously impossible levels of customer-specific detailing. Conventional profiling of silicon nitride materials does not exhibit the requisite precision to provide such complicated shapes, which is what makes EDM of conductive silicon nitride a revelation and an integral part of modern silicon nitride manufacturing.
Silicon Nitride Ceramics from International Syalons
At International Syalons, we have demonstrated an ongoing commitment to innovation within the field of advanced silicon nitride ceramics. We are the UK’s leading producer of silicon nitride based advanced ceramics, and are continuing to develop industrial solutions for your unique applications.
If you would like to learn more, refer to our previous article on Electro Discharge Machining (EDM) of Sialon Ceramics