Cutting Strong Materials: Silicon Carbide & Aluminium Oxide Techniques

[sid_galt]

How are materials like Silicon Carbide or Aluminium oxide which are strong and have high melting points shaped and cut? Just wondering.

Is a diamond tipped cutter used or something?

 

[brewnog]

As I understand it, they are sintered. The cutting surfaces aren't made from solid silicon carbide/tungsten carbide/whatever. They're lots of little particles, essentially held in by cement.

 

[PerennialII]

... think so too, don't think there is much else you can use except sintering, essentially a diffusion process.

 

[NateTG]

Well, you can actually cut something with material of the same hardness, but it wears the tools out quickly.

That said, if you start looking at 'exotic' cutting materials like diamond, cubic boron nitride, and so on, what often happens is that the cutting material is in a matrix of something else. This is useful for shaping, and also because the harder cutting materials tend to be brittle (and friability is a desirable characteristic at times.)

Grinding wheels (which is where AlO and SiC are popular) are typically formed, not cut.

 

[Astronuc]

Most ceramic and many metal products are formed using 'near net shape' processes. The green ceramic is sintered to the final product.

To cut, a substance, one simply needs a harder substance, and in most cases, this means a diamond coated surface on a metal substrate, e.g. copper disk, with water cooling.

On could also use a plasma etch, but that is often more energy intensive and therefore more expensive.

 

[NateTG]

As I understand it, they are sintered. The cutting surfaces aren't made from solid silicon carbide/tungsten carbide/whatever. They're lots of little particles, essentially held in by cement.

Sintering is a process for forming objects from powder, usually used for ceramics. http://en.wikipedia.org/wiki/Sintering

Grinding wheels are usually not sintered:

http://www.mmsonline.com/articles/120003.html