K_2SO_4晶体枝状形貌及结晶学模型

Dendritic Pattern and Crystallographic Model of K_2SO_4

生长了具有枝状形貌的K2SO4晶体。基于单偏光显微镜下的形貌观察和背散射电子衍射分析,测定了枝晶的生长方向,建立了K2SO4晶体枝状形貌的结晶学模型。研究表明,K2SO4晶体的生长方向为[111]方向和[1—1—1]方向,且两者夹角为114.4°;发育的晶面为(11—0)面,是由[111]晶向和[1—1—1]晶向组成的晶面。K2SO4枝晶具有两种生长模型,当其作为单枝生长时,一个<111>方向的枝体连续发育做主枝,另一个<111>方向的枝体不连续发育作为侧枝;当其多枝同时生长时,<111>方向既可作为一个主枝,又可以作为其它主枝的一个侧枝。两种模型均指示出了K2SO4枝晶生长的不对称性。该研究揭示了结晶学方向在枝晶形成过程中的控制作用。

Abstract： Dendritic patterns of K2SO4 crystal was obtained. After the observation under the polarizing microscope and the analysis based on the electron backscattered diffraction（ EBSD）, the growth direction was determined and the crystallographic model of dendritic-pattern of K2SO4 was established. The results show that the growth directions of K2SO4 are direction [ 111 ] and [ ]-]-1 ] with an included angle of 114. 4% The developmental crystallographic plane is plane （ 110 ）, which is composed of crystallographic directions [ 111 ] and El- ]-1 ]. For K2SO4, there are two models for dendritic growth. When KESO4 is growing as a single dendrite, the dendrite with the direction of 〈 111 〉 will develop continuously into the main branch, while the other one with the direction of 〈 111 〉 forms the lateral branch in discontinuous development. When many K2SO4 are growing concurrently, the dendrites with the direction of 〈 111 〉 can form not only the main branches, but also lateral branches attached to other main branches. The study reveals the function of crystallographic direction on controling the formation of the dendritic crystal.