抄録
In order to nitride aluminum chips with 2 mm in size, the mixtures of aluminum chips and atomized powder of aluminum were caused to react with nitrogen. Nitriding of aluminum chips was completely accomplished at 1000°C by adding Y(NO3)3⋅6H2O to the mixture with 40% of chip content. The mixture with 50% of chip content was also completely nitrided by heating at 1300°C. Furthermore, adding Y(NO3)3⋅6H2O, Al chips without atomized powder were able to be nitrided up to 70% of conversion. The conversion of this product was increased up to 97% by nitriding again.
The atomized powders soaked up the melt of Al chip to make a lump of Al at 900°C. In general, the formation of Al lump makes nitriding difficult. However, yttrium which existed between Al grains in the lump seemed to transport nitrogen atoms. Therefore, the nitriding rate is enhanced in the initial stage to generate a large amount of reaction heat enough to evaporate Al or Al2O vapor, which causes the rapid nitriding in vapor phase.
The products contained about 0.8 wt% of oxygen. The oxygen content tends to decrease with the increase in Al chips in raw materials.
