Powder Metallurgy Molybdenum: Influence of Powder Reduction Processes on Properties

Dense SiCf/MoSi2 composite via liquid silicon infiltration

“…Additionally, the SiC peaks become sharper and more intense after the LSI process, indicating the occurrence of recrystallization of SiC grains. The reactions involved are as follows …”

“…Additionally, the SiC peaks become sharper and more intense after the LSI process, indicating the occurrence F I G U R E 1 Steel die used for shaping the composites of recrystallization of SiC grains. The reactions involved are as follows [17][18][19] On the basis of the above reactions, the mass content of Mo (ω Mo ) in the SiC f /Mo can be calculated using Equation (5), while the average porosity of the Mo matrix (P Mo ) as a function of ω Mo can be calculated using Equation (6).…”

Preparation and Characterization and Reducing Properties of MoO3 Nano-Fibers

“…With the rapid development of hightech, material properties of molybdenum and its alloys in many aspects of the request beyond the traditional performance. For getting high performance molybdenum metal materials, ultra-fine powders of molybdenum is its first step (Tuominen 1980). The methods of ultrafine Mo powder preparation are traditional MoO 3 reduction method, hydroxyl thermal decomposition method, molybdenum chloride vapor method, molybdenum chloride pyrolysis method, laser flash method, and microwave plasma method, etc.…”

“…Just because of molybdenum trioxide is orthogonal layered structure, and molybdenum dioxide is rutile structure.As we know, the reduction process of nanofibers molybdenum trioxide is a very complicated local chemical processes, including following steps (Tuominen 1980, Thorsten 2001): 1. adsorption of reduction gas 2. the chemical reaction between molybdenum oxide with the hydrogen molecules 3. changes in crystal chemistry and the desorption of gas in the reaction products The first step of reduction process of molybdenum trioxide is mainly broken of crystal at 450°C or more, because of the molybdenum dioxide is gradually began to be formed on the surface of molybdenum trioxide and the layer of molybdenum dioxide could be peeled off, and the crystal of molybdenum trioxide could be broken or cracked. As the reaction further, the layer thickness of molybdenum dioxide is more than half the thickness of the crystal of molybdenum trioxide, molybdenum dioxide peeling process could be stopped, the molybdenum trioxide completely transformed into molybdenum dioxide, the shape of crystal was changed generally.…”

Preparation of Superfine Molybdenum Powder by Reduction Process

“…It has been predicted that the applications of molybdenum alloys will rapidly in the future [1]. Superfine molybdenum powder was usually used in the preparation of metallic thin film with high conductivity and corrosion resistance, because refine powder was effective for improving material's properties [2,3]. The methods for preparation of molybdenum powder: ammonium molybdate hydrogen reduction [4], molybdenum carbonyl pyrogenation [5], reducing molybdenum trioxide of evaporation phase with hydrogen [6,7].…”