Abstract:

The experimental of silicon vapor corrosion under different corrosion conditions were carried out on different carbon materials (graphite, C/C, rigid carbon fiber felt (RCFF)), which were used as thermal field materials in silicon crystal growth furnace. The silicification corrosion behavior of the three carbon materials was studied. The results showed that the three carbon materials are easily corroded by silicon vapor at elevated temperature. The composition and microstructure of the three carbon materials have great influence on silicification corrosion behavior. Silicon vapor can infiltrate into interior of the carbon materials by pores and flaws, and then react with substrates to cause corrosion. After silicification corrosion, many cracks are observed on the surface of the three carbon materials, and the carbon fibers are severely destroyed in C/C composites and RCFF. Silicification corrosion level is affected by the form and strength of carbon fibers in C/C composites and RCFF. The corrosion of carbon fiber is necking and cleavage cracking for carbon fiber woven with high strength in C/C composites, while that is fragmenting and pulverizing for short carbon fiber with poor strength in RCFF. The corrosion parameters also have significant influence on degree of silicification corrosion. With the corrosion temperature increasing or corrosion time extending, the silicification corrosion degree for these carbon materials are all increased.

Key words: carbon materials, silicification, corrosion behavior, corrosion parameters