The most difficult part of building this equipment was to make a chamber that is gas-tight but still allows for a test specimen to move at high temperatures. After many different designs, material choices and broken set-ups, we ended up with following design:
- Ceramic plates working as top and bottom of the chamber. The ceramic is named Macor is machinable and we could thereby make holes for gas inlet/outlet and thermo couples.
- Quartz tube (works great with the laser)
- Heat-resistant sealant (type E-COLL)
- Sealing rings (Viton) between glass tube and ceramic plates. The temperature here is much lower than in the test specimen. The Viton rings works for specimen temperatures up to 800 degrees.
- Sealing between test specimen and the Macor plates is received using a combination of ceramics and springs.