復(fù)合氧化物粉末的影響
(中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室， 長沙 410083)
摘 要: 以噴霧干燥法制備的(W, Ni, Fe)復(fù)合氧化物粉末為原料， 在700 ℃、 保溫90 min的條件下進(jìn)行還原， 研究了鑭和釔對(duì)氫氣還原(W, Ni, Fe)復(fù)合氧化物粉末的影響。 采用XRD、 高倍TEM和SEM分別對(duì)還原后的復(fù)合粉末進(jìn)行了物相分析、 晶粒尺寸計(jì)算和形貌觀察， 并對(duì)還原后復(fù)合粉末的Fsss粒度、 比表面進(jìn)行了測定與分析。 研究結(jié)果表明： 不加稀土元素時(shí)， 還原粉末由鎢和γ-(Ni, Fe)兩相組成， 添加一定量的鑭或釔后， 還原粉末中分別出現(xiàn)了新相La(Ni0.75W0.25)O3或Y (Ni0.75W0.25)O3； 未添加稀土元素時(shí)， 顆粒為球形， 添加一定量的稀土元素時(shí)， 顆粒變?yōu)榻蛐位蚨嗝骟w， 并隨著稀土元素含量的增加， 稀土元素對(duì)顆粒形貌的影響增大； 當(dāng)90W-7Ni-3Fe復(fù)合粉末中的稀土元素含量為0~0.8%時(shí)， 隨著稀土元素含量的增加， 粉末dBET粒度、 Fsss粒度和晶粒尺寸均顯著降低， 且粉末的分散性也明顯提高； 當(dāng)添加相同含量的稀土元素時(shí)， 對(duì)粉末性能影響程度的大小順序是釔>La-Y(混合稀土)>鑭。
關(guān)鍵字: W-Ni-Fe復(fù)合氧化物粉末； 氫氣還原； 鑭； 釔
H2-reduction of (W, Ni, Fe) composite oxide powder
XIONG Xiang, WANG Deng-long
（ State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: The (W, Ni, Fe) composite oxide powder synthesized by spray drying was used as raw materials and reduced at 700 ℃ for 90 min in H2 atmosphere. The effect of La and Y on H2-reduction of (W, Ni, Fe) composite oxide powder was studied. Phase composition analysis, crystal size caculation and particle morphology of the reduced powder were measured by X-ray diffraction, TEM and SEM, respectively. The Fsss particle size and special surface area of the reduced powder were also measured. The results show that the phase composition of the composite powder reduced are W and γ-(Ni, Fe) without the rare earth elements, but new phase of La(Ni0.75W0.25)O3 or Y(Ni0.75W0.25)O3 appears in the reduced composite powder with adding La or Y. The particle morphology is spherical without the rare earth elements, but the particle morphology is nearly spherical or polyhedron with adding La or Y, and the effect of rare earth element on particle morphology increases with the increase of rare earth element content. When the rare earth element content is between 0-0.8 %, the dBET , Fsss and crystal size of the reduced powder decrease greatly with the increase of the rare earth element content, and the dispersity of the composite powder enhances distinctly. When the same content of rare earth elements is added, the order of effect degree on powder properties is that Y>La-Y>La.
Key words: W-Ni-Fe composite oxide powder; hydrogen reduction; La; Y
