晶硅炉热场用碳材料在硅蒸汽中的腐蚀行为研究

Corrosion Behavior of Carbon Materials Used in Crystalline Silicon Furnace in Silicon Vapor

对晶硅炉热场用三种碳材料(石墨、C/C复合材料、硬质碳毡)在不同腐蚀条件下进行了硅蒸汽腐蚀实验,研究了不同碳材料的硅化腐蚀行为。结果表明:三种材料的结构组成不同,导致三种碳材料在高温环境下与硅蒸汽发生硅化腐蚀的程度不同,硅蒸汽主要通过材料的孔洞以及缺陷扩散进入材料内部进行腐蚀,腐蚀造成材料表面产生大量的裂纹,并且会造成C/C复合材料以及硬质碳毡材料内部严重的破坏。材料中碳纤维的存在方式以及纤维强度对硅化腐蚀程度有较大影响,C/C复合材料中的腐蚀主要是碳基体和碳纤维的剥离以及碳纤维的缩颈、劈裂等;而由强度较差的短碳纤维为主要组成的硬质碳毡材料的腐蚀最严重,其内部碳纤维出现了明显的碎断、粉化。腐蚀参数对材料硅化腐蚀的程度具有较大影响,随着腐蚀温度的升高以及腐蚀时间的延长,三种碳材料的硅化腐蚀程度均增加。

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.