Preparation of new functional materials using low temperature densification by HIP

采用Hipping压力低温烧结Fe_4N磁性材料和SiO_2非晶复合材料。在高温下，Fe_4N分解，无定形SiO_2与结晶SiO_2结晶。将含Fe_4N粉末的密封胶囊在50-200Mpa、450-550℃的温度下烧结2小时。在200MPa下，当温度为500℃时，试样的相对密度达到97%。在200MPa下，在450℃的温度下，试样的最大饱和磁化强度为182emu/g。在Fe_4N和Fe的混合物中应用了HIP技术，以获得低涡流损耗和高饱和磁化强度。含96wt% Fe_4N的Fe4N-Fe复合材料的电阻率为7.08 * 10^<-5> OMEGAcm，是铁的10倍。在铁中加入70wt%的Fe_4N，铁的损失降低到10w，而纯铁的损失为19w。SiO_2非晶复合材料的热烧结将石英和SiO_2玻璃的混合粉末压制成φ为12mm * 20mm的致密体。在50-200MPa的压力下，在800- 1200cc的温度下，将含有压缩物的耐热玻璃胶囊加热30-240分钟。在100和200MPa下，在120℃的温度下获得了天然玛瑙外观的样品。显微偏振照片表明，晶体为无定形SiO_2基体。在α -石英含量为25wt%的起始混合物中，在200MPa下，在1200℃的温度下加热120分钟，得到的最大密度为2.50g/cm^3。在这种情况下，获得的最大抗弯强度为9.2Kg/mm^2。相当于天然玛瑙的70%。

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.