A study of the impact of reduction conditions on molybdenum morphology

Shape-Controlled Synthesis of Ultrafine Molybdenum Crystals via Salt-Assisted Reduction of MoO2 with H2

“…These two mechanisms have been used extensively to analyze the reduction mechanisms of reduction of MoO 2 . 5,6,14,19 For the pure pseudomorphic transformation mechanism, the main reaction is shown as reaction 1; Mo is generated directly and the reaction interface moves from the particle surface toward the core of the grain, forming a Mo particle with a similar shape to the starting material. However, for the CVT mechanism, a gaseous intermediate transport phase is formed.…”

“…The effects of various reaction parameters, such as the reduction temperature, concentration of water vapor, hydrogen content, and the flow rate of hydrogen gas, on the morphology and size of molybdenum particles were investigated in several studies. ,, However, it is difficult to control the shape and size of Mo crystals successfully by simplified adjusting of these parameters. In the literatures, the method of assisted molten salt syntheses (MSS) was widely used to prepare nano- and microcrystals with controlled shapes and sizes. − In this paper, the salt-assisted hydrogen reduction of MoO 2 was proposed to prepare the ultrafine Mo crystals.…”

“…The industrial production of metallic molybdenum is a stepwise process including the hydrogen reduction of MoO 3 to MoO 2 in the temperature range of 450−650 °C and the further hydrogen reduction of MoO 2 to Mo at the relative higher temperatures (850−950 °C). 3,6,14,16 The reduction mechanisms of molybdenum oxides using H 2 have been investigated by many researchers. 4,6,14,16−18 It is known that the morphology and size of Mo are mainly determined by the process of MoO 2 → Mo.…”

Hybridization of additive manufacturing processes to build ceramic/metal parts: Example of HTCC

“…To improve the organic extraction in reducing atmosphere, the use of a wet debinding atmosphere was used [9], [10] by introducing water in the argon/H 2 gas. Different partial water pressures into the debinding atmosphere were tested in order to found a good compromise between a complete removal of carbon residues and a non-oxidation of the tungsten.…”

Controllable Preparation of Spherical Molybdenum Nano-Powders by One-Step Reduction of APM in Radio Frequency Hydrogen Plasma

“…At present, the industrial production of high-quality molybdenum powder is always achieved through two-stage reduction of MoO 3 (hydrogen reducing MoO 3 to MoO 2 at 600–700 °C, and further reducing MoO 2 to Mo at 850–1100 °C). The molybdenum powders prepared by the hydrogen reduction method usually have large particle sizes of several microns because the molybdenum nucleation and growth process are difficult to control [ 5 , 6 ]. In addition, the sintering temperature of the micron-molybdenum powder must reach 1800–2000 °C and be maintained for several hours to obtain 90% of its theoretical density; the grain size of the compact is tens of microns [ 7 , 8 , 9 ].…”