Deposition of nano-crystalline tungsten carbide powders from gaseous WO_(2)(OH)_(2)

作     者：Markus Ostermann Roland Haubner 

作者机构：TU WienInstitute of Chemical Technologies and AnalyticsGetreidemarkt 9/164-031060 ViennaAustria 

出 版 物：《Tungsten》 (钨科技（英文）)

年 卷 期：2023年第5卷第1期

页      面：136-144页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：Gatan Technische Universität Wien 

主　　题：Tungsten carbide CVT-mechanism WO2(OH)2 Carburation Nano-sized powder Transmission electron microscopy(TEM) 

摘      要：Lower WC grain sizes in the nanometer range have positive effects on the properties of hardmetals(e.g.,hardness),but the established production processes of WC are limited to grain sizes of about 150 *** produce WC powder with grain sizes in the lower nanometer range,an alternative WC production process based on the chemical vapor transport(CVT) reaction of WO_(3) and H_(2)O forming gaseous WO_(2)(OH)_(2) at about 1100 ℃,followed by a carburation reaction with H_(2)/CH_(4)-gas mixtures was *** influences of different process parameters such as furnace temperature,humidity and gas flows were investigated to improve the *** the right set of parameters the produced powder consisted mainly of agglomerated WC grains with a size of about 5 *** the common hexagonal WC phase,the cubic WC1-xphase was stabilized due to the small crystallite *** addition,a thin layer of amorphous carbon was present on the powder surface due to the catalytic methane decomposition on the WC *** amount of oxidic and metallic residues in the product powder was minimized with the parameter optimization and the powder yield was increased up to about 50%.With further optimization of the process parameters and usage of improved flow breakers,the purity and yield of the product powder can be further *** an application in the hardmetal section is not realistic at the moment,applications in the catalysis sector could be considered due to the small grain size and good catalytic activity of the cubic WC1-xphase.