An industrially feasible pathway for preparation of Mo nanopowder and its sintering behavior. (November 2019)

• Record Type: Journal Article
• Authors: Sun, Guo-Dong; Zhang, Guo-Hua; Chou, Kuo-Chih
• Is Part Of: International journal of refractory metals & hard materials. Volume 84(2019)
• Publication Date: 2019-11
• Subjects: Mo nanopowder -- Sintering behavior -- Grain growth -- Hardness; 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.2019.105039
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: In this study, a low-cost, efficient and industrially feasible pathway was developed to prepare Mo nanopowder via a two-stage carbothermic reduction of commercial MoO3 with carbon black at 600 °C and 1050 °C, respectively, followed by deep hydrogen reduction at 800 °C. The sintering behaviors of the prepared Mo nanopowder and micron commercial Mo powder containing different amounts of Mo nanopowder were investigated in the temperature range of 1000 °C–1600 °C. At 1200 °C, the Mo nanopowder was sintered to near-fully densified compact with a relative density of about 95.8%, which was much higher than the value of 70% for commercial Mo powder. For the nanopowder, the grain size dramatically increased when the sintering temperature increased. The hardness of sintered nanopowder at 1200 °C (relative density, 95.8%; average grain size, 1.88 μm) was about 254 HV0.1, which was much higher than the value of 182 HV0.1 as sintering commercial micron sized Mo at 1600 °C (relative density, 93.9%). The addition of Mo nanopowder into micron Mo can noticeably activate its sintering and improve its hardness. Highlights: A low-cost, efficient and industrially feasible pathway was developed to prepare Mo nanopowder. Prepared Mo nanopowder had a much higher sintering activity than micron sized Mo powder. Addition of a small amount of Mo nanopowder noticeably activates the sintering of micron sized Mo powder.