The key to proper specimen preparation of hard / tough ceramic materials such as silicon nitride (Si3N4) is to grind with a semi-fixed abrasive (polycrystalline diamond on a metal mesh cloth), followed by the use of CMP (chemical mechanical polishing) techniques using colloidal silica.
SECTIONING
Diamond Wafering blade - medium grit / low concentration
MOUNTING
Castable Mounting with Epoxy or Acrylic resins
POLISHING
Abrasive/surface |
Lubricant |
Force/ sample |
Speed |
Time |
| 30 um DIAMAT diamond suspension on CERMESH Metal Mesh cloth | 5-10 lbs | 200/200 rpm |
Until plane | |
| 6 um DIAMAT diamond on TEXPAN polishing pad | SIAMAT colloidal silica | 10 lbs | 200/200 rpm |
5 minutes |
1 um DIAMAT diamond on GOLDPAD polishing pad |
SIAMAT colloidal silica |
10 lbs |
200/200 rpm |
5 minutes |
SIAMAT Colloidal silca on TEXPAN polishing pad |
|
10 lbs |
100/100 rpm |
5 minutes |
 |
Silicon Nitride polished with CMP techniques |
 |
Silicon Nitride polished by conventional 9,6,3,1,0.25 um diamond steps. Note that the damage is not removed even after long polishing times. 400X (DIC) as polished |