Al_2O_3, amorphous, KBr pellet, 1:500 | DOCCD

Step	Chronology	Type	Process	Changes
#1	before layer formation	mixing	Batch for the sol-gel technique: mixing of the compounds aluminium secondary butoxide [Al(OCHCH $_{3}$ CH $_{2}$ CH $_{3}$ ) $_{3}$ ], ethylacetoacetate [CH $_{3}$ COCH $_{2}$ COOC $_{2}$ H $_{5}$ ], propan-2-ol [C $_{3}$ H $_{7}$ OH] and H $_{2}$ O; stirring the mixture for six months
#2	before layer formation	thermal	Triggering of the batch by heat for gelling and drying at 383 K	homogeneous gel was produced and dried
#3	before layer formation	thermal	Annealing of the sol-gel product at 873 K to remove organic groups and water from the structure	pure amorphous Al $_{2}$ O $_{3}$ was produced, the amorphous state was approved by XRD, DTA, TG and NMR measurements
#4	before layer formation	mechanical	Grinding the amorphous Al $_{2}$ O $_{3}$ and seperation of the grain size fraction <1 µm by sedimentation in acetone	production of a powder, grain size < 1 µm
#5	before layer formation	mixing	Mixing the Al $_{2}$ O $_{3}$ powder and KBr in a mass ratio of 1:500
#5	during layer formation	pressure	Production of a 200 mg KBr pellet under vacuum with a pressure equivalent of 10 tons	pellet with 1.27 cm diameter and 200 mg

Comments

The steps 1-3 comprise the sol-gel technique and were applied in the laboratory of Rüdiger Nass at the Institute for New Minerals, Saarbrücken.