硅灰石制备二氧化硅材料过程中的多型转变  

POLYTYPE TRANSFORMATION DURING SYNTHESIS OF SILICA MATERIALS WITH NATURAL WOLLANSTONITE

作　　者：赵文俞[1] 彭长琪[1] 张清杰[1] 

机构地区：[1]武汉理工大学材料复合国家重点实验室,湖北武汉430070

出　　处：《矿物学报》2004年第4期359-365,共7页Acta Mineralogica Sinica

基　　金：国家863计划资助项目(863 2001AA339020)

摘　　要：研究了1Tr型硅灰石酸解形成二氧化硅材料过程中的多型转变和浸蚀方向。结果表明:1Tr型硅灰石在2mol/LHCl溶液中的酸解浸蚀方向严格受晶体结构控制,酸解初期晶粒首先沿{100}面方向浸蚀,结果导致衍射面的衍射强度增大;随着酸解时间的延长,[SiO4]单四面体与[CaO6]八面体共棱连接方向成为主要浸蚀方向,在XRD图谱中表现为d=0.298nm衍射峰一直保持较大的衍射强度。特征衍射峰的相对强度变化特征表明,1Tr型硅灰石酸解形成二氧化硅过程中晶体结构发生了由1Tr型向2M型的多型转变,且酸解60min后的XRD图中各衍射峰的相对强度更接近于2M型硅灰石的衍射强度范围,其标志是d=0.299nm衍射峰成为最强衍射峰。推测d=0.298nm左右的衍射峰强度在40min前主要来自1Tr型硅灰石的衍射面,40min以后变为2M型硅灰石的衍射面,并对1Tr型硅灰石的JCPDS29 372卡片数据进行了讨论。Polytype transformation and etching orientation of the 1Tr-type wollastonite crystals in the process of synthesizing silica materials in the 2 mol/L HCl solution were investigated with the XRD　method.　It was confirmed that wollastonite crystals had been mainly etched along the {100}-plane orientation　at the beginning of acid hydrolysis, based on the increase of diffraction intensities of 100, 200 and 300 reflection peaks with prolonging time of acid hydrolysis. The co-edge orientation between \ octahedron and [SiO_4] single tetrahedron became the main etching orientation when 1Tr-type wollastonite was　in the　2 mol/L HCl solution for a long time, which can be confirmed by the stronger diffraction intensity of the peak at about (d=0.298) nm in the range 10-120 min. These results showed　that the etching　orientation of acid hydrolysis is strictly　controlled by the crystal structure of wollastonite. The polytype transformation of wollastonite from 1Tr- to 2 M-type was discovered　by employing the variation character of diffraction peaks at about d=0.384, 0.352, 0.332, 0.309, 0.298, 0.272 and 0.256 nm. The relative intensities of major diffraction peaks in the XRD pattern obtained at 60 min are closest to those　of 2 M-type wollastonite, whose symbol is that the diffraction intensity of 320 reflection peak with d=0.299 nm of 2M-type wollanstonite is strongest. At the same time, the diffraction intensity of the peak at about (d=0.298) nm mainly originates from the 120 reflection pleak　with (d=0.298 nm) of 1Tr-type wollastonite until 40 min, but from the 320 reflection peak　with d=0.299 nm of 2M-type wollanstonite in the range 40-120 min. In addition, the diffraction data of 1Tr-type wollastonite listed in JCPDS 29-372 card are additionally discussed in this paper.

关 键 词：硅灰石 酸解 二氧化硅 制备 浸蚀 XRD 硅材料 衍射强度 晶体结构 相对强度 

分 类 号：P578[天文地球—矿物学] O734[天文地球—地质学]