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.
XPS Data for Sapphire
XPS Data for Alumina
Carbon Dioxide Snow Cleaning has been performed on many ceramics and have had success in cleaning SiC coated graphite susceptors. Another area of interst is in removing deposition residues from ceramics shields and reactor zones. This works when there is good thermal mismatch between the ceramic and deposited material as long as no reactions occured.