Rareearthuhrafineparticlehasbeenpaidagreatattentiontoinrecentyearsaroundtheworldbecauseofitsincreasingapplicationsinfunctionalmaterials.Preciseceramicsisatypicalexample.Thepartiealsizesfortheproductnowavailableareusuallyintherangeof100-1000(1=1010m)withlargespecificsurface,say,70—120m2/g.Ultrafinepowdersareusuallyclassifiedinto3gradesdependingontheirpar-ticlesizes,thusthefirstbeingintherangeof10—
