Microstructure and properties of La2O3 doped W composites prepared by a wet chemical process. (August 2017)

• Record Type: Journal Article
• Authors: Li, Jianfeng; Cheng, Jigui; Wei, Bangzheng; Zhang, Minglong; Luo, Laima; Wu, Yucheng
• Is Part Of: International journal of refractory metals & hard materials. Volume 66(2017)
• Page Start: 226
• Page End: 233
• Publication Date: 2017-08
• Subjects: Wet chemical method -- Ultra-fine particles -- La2O3/W composites powders -- Core-shell structure; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2017.04.004
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: La2 O3 /W composite powders were prepared by a wet chemical method, using ammonium metatungstate (AMT) and lanthanum oxides (La2 O3 ) as raw materials. La2 O3 /W composite materials were obtained by sintering the powder compacts at 2200 °C. The La2 O3 /W composite powders were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) coupled with energy dispersive spectrum (EDS) and microstructure of the La2 O3 /W composites was characterized by SEM and EDS. The results showed that the La2 O3 /W composite powders have polyhedral shape with particle size of 100–200 nm and some La2 O3 particles were wrapped up by tungsten particles. The highest relative density of 96.93% was obtained for the composites containing 0.6 wt% La2 O3 . Maximum bending strength and Rockwell hardness reach 434 MPa and 70.3HRA, respectively, for the 0.6%La2 O3 /W composites. Scanning electron microscopy observations reveal that the La2 O3 -W core-shell structure still remains in the sintered La2 O3 /W composites. Highlights: A wet chemical method was used to prepare the La2 O3 /W composite powders. The La2 O3 /W composite powders have core-shell structure with La2 O3 particles wrapped up by tungsten particles. The addition of La2 O3 refines the grain size and increases the mechanical properties of the La2 O3 /W composite.