Dear Mr. Riva:

Based upon the succeeding data you may see what the reason is for the different thermal behaviour of the body during firing. It shows the thermal range of formation of the quartz and cristobalite modifications

• Low (b) quartz (< 537°C) d = 2.65

• High (a) quartz (>573°C) d = 2.60

• Cristobalite (< 270°C) d = 2.32

• Cristobalite (> 270°C) d = 2.17

See in the file attached the influence of different elements and minerals on the ceramic body.

Regards

H.G.Dill

Dear Professor Harald G. dill

So  the less shrinkage is due to the presence of cristobalite?

Thanks in advance..