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金属Ti和Zr因其优异的气体吸附特性而被广泛地用作超高真空获得的气体吸附剂.常温常压下,它们均为密排六方(h.c.p.)结构;当温度或压力增高时便发生相应的结构相变:Ti在温度高于882℃时,由h.c. p.结构变为体心立方(b.c.c.)结构,即高温相结构;而Zr则在 3.9 ×10~8 Pa以上的高压下,变为ω相结构,即高压相结构. 纳米材料的重要特征之一是具有较大的比表面积,比表面积增大必将增强其气体的吸附能力.因此,纳米Ti和Zr的制备及其气体吸附特性的研究对真空获得技术具有重要意义.就其结构而言,比表面积的增加导致能量升高将可能诱发其原结构的不稳定性,即可能发生因颗粒细化诱导的相变.这便为获得一些具有反常结构的新材料开辟新的途径.本文报道Ti和Zr这方面探索的结果,以及采用X射线衍射技术分析溅射法制备的纳米Ti和Zr的晶格结构特征.其结果表明:用溅射法制备的金属Ti和Zr纳米材料在常温常压下,Ti具有b.c.c.高温相结构;而Zr则具有只有在高压下才能形成的ω相结构.
Metals Ti and Zr are widely used as gas adsorbents for ultra-high vacuum due to their excellent gas adsorption properties, all at a hcp structure at ambient temperature and pressure, and occur at elevated temperatures or pressures Corresponding structural phase transitions: Ti is transformed into a body-centered cubic (bcc) structure, ie, a high-temperature phase structure at a temperature higher than 882 ° C, whereas Zr increases to a high pressure of 3.9 × 10 -8 Pa or more ω phase structure, ie, high-pressure phase structure.One of the important features of nanomaterials is the large specific surface area, and the increase of specific surface area will enhance the adsorption capacity of the gases.Therefore, the preparation of nano-Ti and Zr and their gas adsorption properties Is of great importance to the technology of vacuum access.In terms of its structure, the increase of specific surface area leads to the instability of its original structure, which may lead to phase transformation induced by grain refinement And get some new ways to open up new ways for the new materials with anomalous structure.This paper reports the results of the exploration of Ti and Zr and the lattice structure characteristics of Ti and Zr nanostructures prepared by the sputtering method by X-ray diffraction.The results show that: Prepared by sputtering Of Ti and Zr nanomaterials have a b.c.c. high-temperature phase structure at room temperature and normal pressure, whereas Zr has an omega phase structure that can be formed only under high pressure.