超临界甲醇中前驱物对制备超细镍粉体的影响

The Effect of Precursors on the Preparation of Ultrafine Nickel Powder by using Supercritical Methanol

摘要:

本文以不同的镍基前驱物（氧化镍、乙酸镍、硝酸镍）在超临界甲醇条件下制备超细镍粉体，考察了体系温度、压力、反应时间以及前驱物种类对制备超细镍粉体的影响。通过SEM和XRD对制备产物的形貌和物相进行表征分析。结果表明，超临界甲醇的还原性随着温度和压力的升高而显著增强，在反应体系中，甲醇既起到溶剂作用又起到还原剂的作用。此外，通过考察前驱物种类对制备过程的影响可知，前驱物的种类对制备超细镍有显著的影响，乙酸镍在超临界甲醇250 ℃，9 MPa条件下即能够得到纯的超细镍，硝酸镍则需要更高的温度和压力（280 ℃，14.0 MPa），而以氧化镍为前驱物时即使在300 ℃，20 MPa的条件下也只得到镍和氧化镍的混合物。

Abstract:

Nickel power was synthesized using supercritical methanol with different nickel precursors (NiO, Ni(CH3COO)2, Ni(NO3)2). The impacts of temperature, pressure, reaction time, and kinds of precursors on the preparation of nickel, were investigated. XRD and SEM were applied to analyze the composition and morphology of the synthesized products. Results showed that the reducing capacity of supercritical methanol was enhanced obviously with the increasing of temperature and pressure. In the reaction system, methanol both played roles of reaction medium and reducing agent. In addition, it was known by studying the influence of precursor kinds on the process that the kind of precursor had a great effect on the preparation of ultrafine nickel. Pure ultrafine nickel could be obtained at the supercritical methanol of 250 ℃, 9 MPa using Ni(CH3COO)2 as precursor. While more higher temperature (280 ℃) and pressure (14.0 MPa) were needed for Ni(NO3)2. When NiO was used as precursor, the mixture of Ni and NiO was obtained even at the more drastic condition of 300 ℃ and 20 MPa.