Ceramics
Carbon Dioxide Snow cleaning was performed on several ceramics including sapphire and alumina plates. The surfaces were examined before and after with optical microscopy and x-ray photoelectron spectroscopy. The ceramic samples were taken from a supply of parts kept for ultra high vacuum usage. The surface composition table below shows that initially the alumina and sapphire parts had a hydrocarbon content of 49% and 38 atomic %, respectively. After cleaning, the hydrocarbon contents were lowered to 24% for the alumina sample and 17% for the sapphire sample. These reductions in surface hydrocarbons were on the order of 50%. Surface compositions values are listed below.
Snow Cleaning of Sapphire and Alumina Ceramics
XPS Data for Sapphire
|
Element
|
Before Cleaning
|
After Cleaning
|
|
Al
|
25
|
32
|
|
O
|
32
|
46
|
|
C
|
38
|
17
|
|
F
|
2
|
4
|
|
N
|
1
|
0
|
|
S
|
2
|
0
|
XPS Data for Alumina
|
Element
|
Before Cleaning
|
After Cleaning
|
|
Al
|
14
|
23
|
|
O
|
31
|
45
|
|
C
|
49
|
24
|
|
F
|
1
|
1
|
|
N
|
1
|
0
|
|
Si
|
5
|
8
|
|
Na
|
1
|
0
|
