Preparation of new functional materials using low temperature densification by HIP

Research Project

Project/Area Number	08650995
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	無機工業化学
Research Institution	Science University of Tokyo
Principal Investigator	ITO Shigeru Science University of Tokyo, Faculty of Science and Technology, 理工学部, 助教授 (10120164)
Project Period (FY)	1996 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥2,200,000 (Direct Cost: ¥2,200,000) Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	HIP / FE_4N / saturation magnetization / corrosion resistance / oxygen content / amorphous / crystalline / silica / 熱間等方圧プレス / 低温焼結 / 磁気特性
Research Abstract	Fe_4N magnetic material and SiO_2 amorphous-crystalline composite were sinterd at low temperature by applying Hipping pressure. At high temperature, Fe_4N decomposes and amorphous SiO_2 with crystalline SiO_2 is crystallized. 1.Hip sintering of Fe_4N The sealed capsule containing Fe_4N powder was hipped at 450-550ﾟC for 2 hours under 50-200Mpa. The maximum relative density 97% was obtained for the specimen hipped at 500ﾟC under 200MPa. THe maximum saturation magnetization 182emu/g was measured for a specimen obtained at 450ﾟC under 200MPa. The HIP technique was also applied to the mixture of Fe_4N and Fe, in order to obtain low eddy current loss and high saturation magnetization. The resistivity of hipped Fe4N-Fe composite with 96wt% Fe_4N was 7.08 * 10^<-5> OMEGAcm, which was ten times larger than that of iron. The iron loss was decreased to 10 W by the addition 70wt% of Fe_4N to Fe, compared with 19 W in pure iron. 2.Hip sintering of SiO_2 amorphous -crystalline composite The mixed powder of alpha-quartz and SiO_2 glass was pressed into a compact with PHI 12mm * 20mm in size.The Pyrex glass capsule containing the compact was hipped at 800-1200ﾟC for 30-240 minutes under the pressure of 50-200MPa. Tne specimens with the appearance of natural agate : were obtained at 120ﾟC under 100 and 200MPa. The polarization microphotograph showed that the crystallites were in the amorphous SiO_2 matrix. Using the starting mixture with 25wt% of alpha-quartz, the maximum density of 2.50g/cm^3 was obtained at 1200ﾟC for 120 minutes under 200MPa. In this case, the maximum bending strength was obtained to be 9.2Kg/mm^2.corresponding to 70% of that in the natural agate.