Preparation and Characterization of MoB Coating on Mo Substrate

Abstract

Abstract:A molybdenum boride (MoB) coating was prepared on molybdenum (Mo) by an in-situ chemical vapor deposition method. To develop a fuller understanding of the effect of depositional conditions on the growth of MoB coating formed on Mo substrate, this paper studied the phase composition and microstructure of the coating at varied conditions. At the same time, the relationships between the growth of the coating in thickness and depositional conditions were also investigated. The phase composition of the coating, which was prepared using 0.2 wt % boron (B), was composed of MoB and Mo 2 B phases. The single MoB phase was obtained using a high B content (above 0.2 wt %). The microstructure of the coating showed that MoB coating could be prepared at temperatures over 900 • C. With the increase of temperature and time, the thickness of the coating increased. The growth of the coating was also influenced by the content of NaF. With increasing content, the thickness of the coating first increased, and then decreased. In addition, the prepared coating had a high hardness (3130.85 HV), and the mass change of the coated sample was only 4.92 mg/cm 2 after isothermal oxidation at 600 • C for 100 h. The MoB coating could provide a good oxidation resistance for Mo at 600 • C.

Preparation of MoB2 Nanoparticles by Electrolysis of MoS2/B Mixture in Molten NaCl-KCl at 700 °C

“…7 In order to further reduce the preparation temperature, solid-state metathesis (SSM) process was proposed to prepare molybdenum borides using MoCl 5 and MgB 2 at above 800 °C, 8 which is by far the most common and effective method for preparing molybdenum borides nanoparticles. 8,14,[16][17][18][26][27][28][29] There are also some other methods for preparing molybdenum borides, such as chemical vapor deposition 10,30 and detonation spray process 31 to prepare molybdenum borides films on Mo foil, MoAlB precursor etching treatment to synthesize lamellar MoB, 9,32 borothermal reduction of molybdenum oxide 2,33 and electrodeposition in molten salt 20,[34][35][36][37][38][39] to synthesize several molybdenum borides (Fig. 1).…”