有機金属塩 前駆体とするNiAl微粉末の合成
1994 年 31 巻 8 号 p. 540-548
詳細
1994 年 31 巻 8 号 p. 540-548
Fine powders of intermetallic NiAl have been synthesized through organometallic salt precursors. The precursors were precipitated as mixtures of Al(OH)2(C6H5COO) and [Ni(N2H4)2](C6H5COO)2 in a water-methanol solvent (50:50). The precursors should have features such as: (1) fine particle size, (2) uniform composition, and (3) low agglomeration to prepare fine intermetallic powders. Fine precursors were obtained from a starting solution of high concentration, however, they were an aggregated mixture. From diluted starting solutions, the obatained precursors were inagglomerated and considered to be composite powders, but they had a large particle size. An intermediate mixture of Ni3C, Al2O3, and C was formed by the thermal decomposition of the precursors at 1000°C. NiAl powder formed by the reaction among the decomposition products at 1500°C in an Ar atmosphere. The mechanochemical activation of the precursors using a planetary ball mill promoted the thermal decomposition of the precursors followed by the formation reaction of NiAl. The effect of the activation was marked for the precursor estimated as a composite particle. The activated precursors showed an increase in ESR signal intensity, suggesting that the formation of organic radicals promoted the thermal decomposition and formation of NiAl fine powders.
