Suwei YAO
,
Zhaohui ZHAO
材料科学技术（英文）
The Fe3O4 films were prepared by in-situ oxidative hydrolysis on chitosan. The structures and characteristics of the prepared Fe3O4 films were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), atom force microscopy (AFM), vibrating sample magnetometry (VSM) and thermogravimetric-differential thermal analysis (TG-DTA). The results show that, (1) the as-synthesized Fe3O4 films are pure Fe3O4 with cubic inverse spinel structure; (2) the network structured film can be obtained at lower temperature, and the compact particle film at higher temperature; (3) the prepared Fe3O4 films are super-paramagnetic, and the saturation magnetization is improved with increasing the reaction temperature, which is 49.03 emu/g at 80℃; (4) the temperature of phase transformation from F Fe3O4 to α-Fe2O3 is about 495℃. Besides, the formation mechanism of Fe3O4 film was also proposed.
关键词:
Fe3O4 film
,
film
,
In-situ
,
Oxidative
,
hydrolysis
Bong-Jae Choi
,
Si-Young Sung
,
Myoung-Gyun Kim
,
Young-Jig Kim
材料科学技术（英文）
The main purpose of this study is an in-situ synthesis of (TiB+TiC) hybrid titanium matrix composites (TMCs) by vacuum induction melting method and to verify its mechanical properties. The melting route was adopted to synthesize the commercial pure titanium (cp Ti) and granular boron carbide (B4C). The reinforcements, the fraction of 10 vol. pct, were formed by adding 1.88 wt pct B4C to cp Ti. After in-situ synthesis of TMCs, electron probe micro-analysis elemental mapping was carried out to confirm the distribution and shape of reinforcements. The cone-on-disk type sliding wear test was also done for the identification of TMCs. It is concluded that (TiB+TiC) hybrid TMCs can be in-situ synthesized and has better wear properties than H13.
关键词:
Titanium matrix composites
,
null
,
null
,
null
Ke LI
,
Jun WANG
,
Da SHU
,
Baode SUN
,
Yaohe ZHOU
材料科学技术（英文）
Cylinder-like in-situ Al/24Si FGMs were produced by using electromagnetic separating process. Si primary phase reinforced layer with volume fraction as high as 16 pct was formed at the outer region of the cylinder-like samples where the local hardness and wear resistance were enhanced remarkably. Moreover, both of strength and ductility in the inner region provided insurance of reliable strength for this as-cast gradient material. It indicated that general mechanical properties such as good wear resistance at the outer region and good ductility in the central part could be obtained with the optimized redistribution of the Si primary particles under the electromagnetic force.
关键词:
FGMs
,
null
,
null
