( School of Materials Science and Engineering，
Hebei University of Technology， Tianjin 300130, China)
摘 要: Sm12.7Fe86.3Nb1合金在不同溫度下氫爆（HD）及氫化-歧化-解吸-再復(fù)合（HDDR）處理時(shí)，100 ℃時(shí)可氫化形成Sm2(Fe，Nb)17Hy，隨著溫度升高氫化速度加快，到400 ℃時(shí)單胞體積最大膨脹了3.38%。超過500 ℃時(shí)Sm2(Fe，Nb)17Hy+H2→SmHy+α-Fe(Nb)發(fā)生歧化，直到900 ℃仍舊存在，故氫爆溫度應(yīng)低于500 ℃。解吸與再復(fù)合過程在超過700 ℃時(shí)可能以SmHy+α-Fe(Nb)→Sm2(Fe，Nb)17+H2方式進(jìn)行。在連續(xù)的HDDR處理過程中，吸氫-歧化在升溫（400 ℃/h）的過程中即已完成，而解吸-再復(fù)合在保溫時(shí)與歧化階段達(dá)到平衡，即SmHy+α-Fe(Nb)Sm2(Fe，Nb)17+H2， 抽真空是使該反應(yīng)向右進(jìn)行的主要驅(qū)動(dòng)力。在HDDR過程中破壞試樣的原顆粒尺寸會(huì)殘留較多的軟磁α-Fe相而惡化氮化后的磁性能，HDDR后殘留的α-Fe相含量均高于退火態(tài)的殘留量，2次循環(huán)后磁粉的矯頑力較高。HDDR使粉末顆粒表面產(chǎn)生裂紋，再復(fù)合后的Sm2(Fe，Nb)17顆粒細(xì)小均勻，尺寸分布在幾十納米到300 nm之間。
關(guān)鍵字: Sm2(Fe， Nb)17型合金; HDDR; 磁性能; 顆粒形貌
WANG Ru， WU Rui-guo， LIANG Zhi-mei
（ School of Materials Science and Engineering，
Hebei University of Technology， Tianjin 300130, China）
Abstract: The hydrogenation-decrepitation (HD) as
well as hydrogenation-disproportionation-desorption-recombination (HDDR) processes for Sm12.7Fe86.3Nb1 alloys were investigated at different temperatures by means of XRD， home-made HDDR equipment and microstructure observations. It shows that the hydrogenation reaction Sm2(Fe， Nb)17+H2→Sm2(Fe， Nb)17Hy can begin from 100 ℃, which is accelerated with increasing temperature. The maximal unit cell volume expansion of 3.38% is found at 400 ℃. The disproportionation reaction Sm2(Fe， Nb)17Hy+H2→SmHy+α-Fe(Nb) begins at 500 ℃ and can continue to 900 ℃. The temperature for HD should be below 500 ℃. The desorption-recombination processes maybe carry out according to the reaction SmHy+α-Fe(Nb)→Sm2-(Fe， Nb)17+H2 above 700 ℃. The hydrogenation-disproportionation processes finish when samples are continuously heated up to 800 ℃ at the heating rate of 400 ℃/h， and the desorption-recombination processes will reach equilibrium with disproportionation process on the basis of SmHy+α-Fe(Nb)Sm2(Fe， Nb)17+H2 and only pumping-vacuum can facilitate the reaction to right. Broken samples on halfway HDDR is detrimental to the magnetic properties because of lots of remained α-Fe phase. The content of α-Fe in HDDR-treated samples is higher than that of annealed samples. Lots of cracks in the particles are found among the HDDR-treated samples， and the size of the recombined Sm2(Fe， Nb)17 particles becomes less than 300 nm.
Key words: Sm2(Fe， Nb)17-type alloys; HDDR; magnetic properties; microstructure of particles
