In a further contribution devoted to this important refractory metal, Sunil Jha of the Climax Molybdenum Company, Sahuarita, Arizona, introduced a significantly different process for making ultrafine molybdenum powder. Now being produced in commercial quantities, the high specific surface area of this product enables fully dense parts to be obtained at lower sintering temperatures. It also makes processing of Mo/Cu and Mo/Ag more cost-effective and the alloys easier to fabricate into electronic components, such as heat sinks and electrical contacts. Agglomerated to improve handling, the ultrafine powder can also be used in MIM feedstocks. In principle, the production sequence for nano Mo is much the same as that described in the previous paper, but in practice it is noticeably different. The patented process involves quenching MoO_3 vapours to form nano molybdenum trioxide (NTO) particles of 50-100 nm grain size (Fig. 25). Surface area of NTO approaches 60 m~2/g and its apparent density is in the range 0.11-0.14 g/cm~3.
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