S0402-2-2 CNT/Mg_2Si/MgO複合分散強化マグネシウム基焼結材料の組織と摩擦摺動特性([S0402-2]粉末成形とその評価(2))

抄録

Porous silica (SiO_2) particles originated from rice husks were coated with carbon nanotubes (CNTs) by using zwitterionic surfactant solution via wet mixing process. Elemental mixture of this hybrid particle and pure Mg powder were consolidated by spark plasma sintering (SPS) process. DTA profile of the elemental mixture powders indicated that a remarkable exothermic heat started at 727K due to the reaction of Mg-SiO_2 to synthesize magnesium silicide (Mg_2Si) intermetallic compounds in solid-state. There was no reaction between SiO_2 and CNTs in DTA result. With increasing the content of CNT/SiO_2 hybrid powders, the relative intensity of Mg_2Si and MgO peaks gradually increased, and resulted in the increment of macro-hardness of the sintered Mg composites. The friction coefficient of the composite under dry condition gradually decreased with increase in the hybrid powders. This is because the abrasive wear was prevented by uniform dispersion of Mg_2Si hard particles in the matrix and the bearing effect and self-lubricant property of nanotubes remarkably reduced the friction between the composite and the counter material (SUS304).