摘要
以普通重质碳酸钙(D50≈38μm)为核相,通过非均匀形核法在过饱和铝酸钠溶液中构建了CaCO_(3)/Al(OH)_(3)核壳复合材料。通过X射线衍射(XRD)、扫描电镜-能谱联用(SEM-EDS)、傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)及X射线光电子能谱(XPS)等多光谱技术,系统揭示了包覆过程中物相组成、界面化学态及键合结构的动态演变规律。实验通过梯度反应时间(2、12和36 h)调控包覆路径,结合SEM-EDS截面形貌分析与XRD物相鉴定,明确了核壳结构的三层模型:方解石型CaCO_(3)核(≈38μm)、C_(3)AH_(6)中间层(300~500 nm)及致密Al(OH)_(3)外壳,其形成遵循“CaCO_(3)→C_(3)AH_(6)→Al(OH)_(3)”的逐步反应路径。FTIR与Raman光谱进一步佐证了界面化学键合路径:FTIR在3664 cm^(-1)处检测到C_(3)AH_(6)的OH伸缩振动特征峰,而Raman在3390~3640 cm^(-1)区间发现C_(3)AH_(6)的晶格振动模式,二者共同证实钙铝间通过Ca—O—Al键实现化学键合,而非物理混合。XPS定量分析表明,表面钙铝摩尔比从2 h的1.45(接近C_(3)AH_(6)理论值1.5)降至36 h的0.08,结合Ca(2p)结合能偏移及Al(2p)化学态转变(Al—O→Al—OH),直接揭示了C_(3)AH_(6)中间相的动态形成及Al(OH)_(3)壳层覆盖机制。多光谱联用策略的创新性在于:通过XRD/SEM-EDS实现物相-形貌协同表征,FTIR/Raman解析键合结构演变,XPS定量追踪表面化学态迁移,三者深度整合突破了单一表征技术的局限性,系统揭示了C_(3)AH_(6)中间相在界面键合中的桥梁作用。该研究为核壳复合材料可控合成提供了理论依据,例如通过调控铝酸钠溶液浓度与反应时间可精准优化Al(OH)_(3)壳层厚度与均匀性,进而提升材料耐候性及界面相容性。该研究通过光谱学技术的多维协同,为CaCO_(3)/Al(OH)_(3)复合材料的界面化学调控及工业应用提供了关键理论支撑。
Using ordinary ground calcium carbonate(D 50≈38μm)as the core phase,a CaCO_(3)/Al(OH)_(3)core-shell composite material was constructed in a supersaturated sodium aluminate solution via heterogeneous nucleation.By multiple spectroscopic techniques,including X-ray diffraction(XRD),scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),Fourier transform infrared spectroscopy(FTIR),Raman spectroscopy,and X-ray photoelectron spectroscopy(XPS),the dynamic evolution of phase composition,interfacial chemical states,and bonding structures during the coating process was systematically revealed.The coating pathway was regulated by reaction time gradients(2 h,12 h,36 h).Combined with SEM-EDS cross-sectional morphology analysis and XRD phase identification,a three-layer model of the core-shell structure was established:a calcite-type CaCO_(3)core(≈38μm),a C_(3)AH_(6)intermediate layer(300~500 nm),and a dense Al(OH)_(3)outer shell,following a stepwise reaction path of“CaCO_(3)→C_(3)AH_(6)→Al(OH)_(3)”.FTIR and Raman spectra further corroborated the interfacechemical bonding path:FTIR detected the characteristic OH stretching vibration peak of C_(3)AH_(6)at 3664 cm^(-1),while Raman identified additional lattice vibration modes of C_(3)AH_(6)in the 3390~3640 cm^(-1)range,collectively confirming chemical bonding(via Ca—O—Al bonds)rather than physical mixing between calcium and aluminum.XPS quantitative analysis demonstrated that the surface Ca/Al molar ratio decreased from 1.45 at 2 h(close to the theoretical value of 1.5 for C_(3)AH_(6))to 0.08 at 36 h.Combined with the Ca(2p)binding energy shift and the Al(2p)chemical state transition(Al—O→Al—OH),this directly revealed the dynamic formation of the C_(3)AH_(6)intermediate phase and the coverage mechanism of the Al(OH)_(3)shell.The innovation of the multispectral coupling strategy lies in:achieving phase-morphology collaborative characterization through XRD/SEM-EDS,analyzing bonding structure evolution with FTIR/Raman,and quantitatively tracking surface chemical state migration with XPS.This integrated approach overcomes the limitations of single-technique characterization and systematically elucidates the pivotal role of the C_(3)AH_(6)intermediate phase in interfacial bonding.The study provides a theoretical foundation for the controllable synthesis of core-shell composites.For instance,optimizing the Al(OH)_(3)shell thickness(300~500 nm)and uniformity by adjusting the sodium aluminate concentration and reaction time can enhance the material s weathering resistance and interfacial compatibility.Through multidimensional synergy of spectroscopic techniques,this work establishes a critical theoretical basis for the interfacial chemical regulation and industrial applications of CaCO_(3)/Al(OH)_(3)composites.
作者
徐妍
包炜军
韦福广
蒋宗辰
XU Yan;BAO Wei-jun;WEI Fu-guang;JIANG Zong-chen(National Engineering Research Center of Green Recycling for Strategic Metal Resources,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;Hezhou Inspection and Testing Center,Hezhou 542899,China)
出处
《光谱学与光谱分析》
北大核心
2025年第12期3498-3507,共10页
Spectroscopy and Spectral Analysis
基金
广西科技基地和人才专项(桂科AD23026087)资助。
