Yunxia Han,Dejiang Ma,Chao Gu,Yu Fu,Yusheng Zhao,Shanmin Wang
Cubic boron nitride (cBN) with superhardness exhibits many exceptional properties rivaling diamond and holds great promise for diverse applications such as advanced cutting tools and high-performance electronic devices, where high-quality single crystals are often highly demanded. However, the synthesis of its large single crystals has been a long-standing challenge, mainly due to a more complex reaction process involved in the growth of cBN when compared with that of diamond, making its growth mechanism largely elusive. In this work, we present a comprehensive investigation on the growth of cBN crystals through a seed method under high pressure using specially designed growth strategies with Li3N as a transport agent, leading to the discovery of the crucial role that the atomic transport rate plays in growing its crystals. The seed crystals are revealed to undergo a reversible cubic → hexagonal → cubic transition sequence at high temperature during a two-step compression process. In addition, the phase diagrams for the formation of cBN in different transport agents are also explored. These findings provide new insights into the mechanism for growing large cBN crystals.
Zhen Zhong Fan,Ji Gang Wang,Li Feng Zhang,Ning Ning Zhan,Gui Jin He
Methacrylated hyperbranched polyglycerol (HPG-MA) is successfully synthesized through transesterification by controlling the ratio of HPG to glycidyl methacrylate (GMA). The concentration of the dye or phase transporter, temperature, contact time, and molecular weight of phase transporter were taken into consideration to evaluate the removal ratio and transfer capability. With malachite green optimized as a model dye, HPG-MA could reach a maximum adsorption of 990 mg/g at the feed concentration of 1 g/L, and the removal ratio is 99% compared with ~20 h for other reported phase transporters, which indicates that HPG-MA is a novel phase transporter. HPG-MA can absorb dyes in aqueous solutions, which can be ascribed to the existence of a cavity structure and abundant ether groups. We believe that HPG-MA can have potential applications in the removal of dyes from aqueous solutions due to its high adsorption capacity and eco-friendly nature.
危险品化学品经营许可证（带存储）