HTR堆内碳素构件孔结构及吸湿特性研究

通过压汞法、N₂吸附法，结合SEM研究了石墨（IG-110）和含硼炭砖（BC）的孔结构，采用XPS分析了材料表面基团，测试了两种材料在不同湿度环境下的动态吸湿过程，分析了孔结构、表面基团、环境湿度对吸湿量的影响，为高温气冷堆（HTR）堆内碳素构件的防潮、除湿提供科学参考。结果显示：BC拥有发达的5 μm以上开口大孔，存在广泛的中孔级别裂隙；IG-110则绝大多数为开口孔隙，1～5 μm的孔隙较为集中。开口孔径的大小和数量是影响吸湿的重要因素。BC平衡吸湿量明显大于IG-110平衡吸湿量；两种材料在不同湿度条件下初始2 h内的吸湿量急速增长；不同湿度条件下，一般在5～8 h内都能达到平衡，在25 ℃下湿度为60%～90%时平衡吸湿量随湿度呈线性关系。

Pore Structure and Moisture Absorption Property of Carbon Materials in HTR

In this work ,the dynamic moisture adsorption processes and influence factor analysis of moisture adsorption property of graphite (IG‐110) and boron carbide (BC) were studied ,which are significant for moisture proof and dehumidification in high tem‐perature gas‐cooled reactor (HTR) .The micropore structures were studied by mercury porosimetry ,N2 adsorption and SEM ,and the surface functional groups were character‐ized by XPS .BC possesses a large amount of closed pores ,with abundant opening pores above 5 μm and slit at mesoporous level ;whereas most pores in IG‐110 are opened with the size between 1‐5 μm .According to this study ,the size and the amount of pores are both key factors to moisture adsorption properties .The equilibrium moisture adsorption content of BC is obviously larger than that of IG‐110 ,with a rapid grow th of moisture absorption content for both materials in the initial 2 h .Under different moisture condi‐tions ,the absorption equilibriums of two materials are generally achieved in 5‐8 h ,and the equilibrium moisture absorption contents are linearly with the humidity in the range of 60%‐90% at 25 ℃ .