氮吸附表征超低比表面积的技术突破及其应用  

Breakthrough and Application of Ultra-low surface area Measurement by Nitrogen Physisorption Method

作　　者：杨正红 于海龙 袁新华 孙志昂 高岩 Yang Zhenghong;Yu Hailong;Yuan Xinhua;Sun zhiang;Gao Yan(Physichem Instruments Ltd.,Beijing 102200;Henan Changxing Industrial Co.,Ltd.,Zhengzhou Henan 450000)

机构地区：[1]理化联科(北京)仪器科技有限公司,北京102200 [2]河南长兴实业有限公司,河南郑州450000

出　　处：《现代科学仪器》2021年第4期56-62,共7页Modern Scientific Instruments

摘　　要：α氧化铝、锂电池正负极材料、原料药及其辅料和膜材料的比表面积值一般都很低。对于比表面积小于0.2m^(2)/g的样品,用一般的物理吸附分析方法很难达到质量控制的重复性要求。为了解决超低比表面材料的质量控制的痛点问题,通过严格控制仪器内部气体的温度、管路的死体积和压力传感器的测量精度,可以实现0.2m^(2)/g左右标准样品比表面积测定的长期稳定性,表现出很高的准确性、客观性和可靠性。对0.04m^(2)/g的样品实现重复性测定,突破了传统氮吸附比表面分析的极限,进入氪气测定比表面的范围,成功实现了用氮气代替氪气进行超低比表面积测定。结合iBox 26智能脱气技术,可以实现自动控温及自动判断脱气完成时间,使样品预处理保持条件一致,为产品的质量控制奠定了坚实的基础。这些新技术的采用,可以使氮吸附测定比表面积的下限极值延伸至0.005m^(2)/g,确保了超低比表面测量的极致精度,并且在机械泵和1000torr压力传感器的P/P_(0)可重复下限从5×10^(-3)下探到1×10^(-5)。这不仅在不增加硬件的基础上满足了氪吸附的测定要求,也满足了微介孔材料的孔径分析要求,还为纳米薄膜的孔径分析建立了新的方法。Some materials have very low surface area includingα-alumina,battery materials,API and its excipients as well as film materials.If specific surface area(SSA)is less than 0.2m^(2)/g,measurement with repeatability is difficult to meet request of quality control by a regular physisorption analyzer.This paper introduced some new developed technologies for ultra-low SSA measurement based on nitrogen adsorption method,which can be worked down to 0.005 m^(2)/g,and get very good repeatability against samples about 0.04 m^(2)/g,with controlling the gas temperature strictly inside the instrument,a constant void volume technology and raising the transducer precision by electronic design.The system capability equipped new technologies broke through the limit of traditional nitrogen physisorption method and covered krypton measurement range for ultra-low SSA determination.Moreover,the lower limit measurement of P/P_(0) with a mechanical pump and 1000 torr transducer is detected down to 1×10^(-5),which not only meets the requirements of krypton adsorption,but also meets the requirements of pore size analysis on micro-mesoporous materials without extra hardware.Also,a new method for pore size analysis of nano-films with ultralow sorption may be established.

关 键 词：氮吸附 超低比表面积 氪吸附取代 iPore 400 死体积恒定 薄膜孔径分析 

分 类 号：TP2[自动化与计算机技术—检测技术与自动化装置]