نتایج جستجو برای: Amorphous phase
تعداد نتایج: 621232 فیلتر نتایج به سال:
In the present study phase transformation of silicon and silica during milling in different atmospheres was investigated. The silicon powder was subjected to high energy ball milling in ammonia (25%) atmosphere. The milled powder was subsequently annealed at 1200 ◦C for 1 hour. In another test a mixture of AlN and amorphous silica (micro silica) was subjected to high energy ball milling. The m...
in this research, mechanical alloying was used to produce ti-50al, ti-45al-5cr and ti-45al-5w (at%) alloys. the effect of ternary addition (cr and w) on microstructure and production efficiency of tial alloy were investigated. alloying was performed in a planetary mill and the milling time varying from 5 to 70h. the structural evaluation in these powders was done by x-ray diffraction (xrd) tech...
The effects of mechanochemical treatment of monoclinic zirconia in high energy planetary ball mill on its phase transformation were investigated. The mechanical treatment in ball mill reduces the grain size, increases microstrain, and causes phase transition to metastable nanostructured tetragonal and cubic phases. XRD and TEM results show considerable amounts of amorphous phase during ball mil...
In this study, the crystallization behavior of melt-spun Al87Ni10La3 amorphous phase was investigated by using X-ray diffraction and non-isothermal differential thermal analysis techniques. The results demonstrated that the amorphous phase exhibited two-stage crystallization on heating, i.e., at first step the amorphous phase transforms into α-Al phase and at second step Al11La3 and Al3Ni inter...
In this research, mechanical alloying was used to produce Ti-50Al, Ti-45Al-5Cr and Ti-45Al-5W (at%) alloys. The effect of ternary addition (Cr and W) on microstructure and production efficiency of TiAl alloy were investigated. Alloying was performed in a planetary mill and the milling time varying from 5 to 70h. The structural evaluation in these powders was done by X-ray diffraction (XRD) tech...
This work is focused on the effect of amorphous SiO2 addition on the phase transformation and microstructural evolution of ZrO2 particles. Considering the structural similarities between the amorphous ZrO2 and its tetragonal structure, XRD results showed initial nucleation of metastable tetragonal ZrO2 from its amorphous matrix upon heat treatment. This metastable phase is unstable in pure ZrO2...
TiO2/SiO2 nanocomposite with molar ratio 1:1 was synthesized by a free calcination sol-gel method using titanium tetra chloride and tetraethylorthosilicate as raw materials. In the composite, TiO2 nanocrystals are highly dispersed in the amorphous SiO2 matrix and the mater showed size quantization effect arising from the presence of extremely small titanium oxide species having a low coordinati...
The work presented here was motivated by the premise that the amorphous state serves as a medium to study cocrystal formation. The molecular mobility inherent to amorphous phases can lead to molecular associations between different components such that a single crystalline phase of multiple components or cocrystal is formed. Cocrystallization pathways and kinetics were investigated from amorpho...
Ge(2)Sb(2)Te(5) (GST) is a technologically very important phase-change material that is used in digital versatile disks-random access memory and is currently studied for the use in phase-change random access memory devices. This type of data storage is achieved by the fast reversible phase transition between amorphous and crystalline GST upon heat pulse. Here we report pressure-induced reversib...
the nanocrystallization of co67fe4cr7si8b14 amorphous ribbons which prepared by planar flow melt spinning process (pfms) was investigated. crystallization of the ribbons was studied by differential thermal analysis (dta), x-ray diffraction (xrd) and transmission electron microscopy (tem). the dta result of amorphous ribbon at heating rate of 10˚c/min showedoccurrence of phase transitions in two...
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