Effect Of Isothermal Annealing Research Articles

Resistivity study of the annealing kinetics of thin vanadium films

This vanadium films with thicknesses ranging from 40.7 nm to 214.5 nm were evaporated onto molybdenum glass substrates at temperatures of 143, 228, 252 and 293 K and were studied in a vacuum of 10 -8 Pa. The effect of isothermal annealing on these films was examined. The decrease in the film resistance with increasing annealing time is a first-order kinetic process which can be attributed to the random removal of structural defects from the films. The free energies of activation required to remove the structural defects ranged from 0.84 eV to 1.54 eV for various films at various annealing temperatures (293–496 K).

二，三の非晶質合金の等温熱処理による磁性の変化

Effects of isothermal annealing (125∼490°C, 5∼1300 min) on the magnetic properties, electrical resistivity as well as tenacity have been studied for rapidly quenched amorphous Fe80P13C7, Fe75Si15B10, Co74Si10B16 and Fe5Co70Si15Br10 alloys. The results are summarized as follows :(1) The magnetic properties of all the alloys change remarkably by the annealing. (2) The coercive force of the alloys is minimum when annealed for about 10∼100 min at the temperatures, about 40∼120°C lower than the crystallization temperatures of the alloys. (3) The hysteresis loops for Co74Si10B16 alloy annealed at 300∼490°C for about 10∼100 min and those for Fe5Co70Si15B10 alloy annealed at 125∼470°C exhibit asymmetrical and unusual shapes. (4) The values of electrical resistivity of these alloys in the as-quenched state are in the range between 160∼240 μΩ·cm. With annealing at various temperatures between 200 and 400°C, no change of electrical resistivity, is observed except for Fe80P13C7 alloy annealed at 400°C. (5) After annealing at around 300°C, Fe80P13C7, Fe75Si15B10 and Fe5Co70Si15B10 alloys become brittle, while the tenacity of Co74Si10B16 alloy is maintained even after annealing at 490°C for 1 h.In order to know the effect of pre-heat treatment on the stabilization of these magnetic properties, isothermal annealing at around 250°C is carried out for the Co74Si10B16 and Fe5Co70Si15B10 alloys, which have been pre-annealed at 400°C for 30 min. It is found that the magnetic properties of both alloys are not stabilized by this pre-annealing.

Changes in the main TL glow peak of γ-irradiated CaSO 4: Dy phosphors after isothermal annealing

The effects of isothermal annealing, at various temperatures and for the same time, on the main TL glow peak of 60-Co γ-irradiated CaSO 4: Dy phosphors are described. Changes in the glow curve shape and shifts of the peak temperature are observed: the higher the annealing temperature, the higher the peak temperature. The experimental results are compared with those calculated by the continuous distribution of trap depths proposed by us in previous work. The agreement is fairly satisfactory.

Electrical properties and hopping transport in amorphous silicon carbide films

Thin films of amorphous SiC are prepared by rf-sputtering and the conductivity studied in the temperature range 300 K ⩾ T ⩾ 80 K both as a function of temperature and as a function of the applied field. Although a few other mechanisms of current transport were observed, much of the dc conductivity was found to be due to hopping between localized states. Mott's exp(T − 1 4 ) law is obeyed at lower temperatures and the values of the significant Mott's parameters obtained from the results are quite realistic. The dc conduction at room temperature, at applied fields of the order of 10 5 V/cm, is explained by field-assisted hopping. The ac conductivity obeys the ω 0.8 law at lower frequencies and saturates at frequencies above 100 kHz. It also shows a T 1 dependence. The effect of isothermal annealing is systematically studied.

The effects of annealing on cold-worked Zr3Al

A study has been made of the effects of isothermal annealing on the hardness, the tensile properties and the microstructure of cold-worked Zr/sub 3/Al (L1/sub 2/ type). For material rolled to a true strain of 0.29, complete recrystallization accounts for a recovery of hardness of 65 to 70 percent and for a reduction in yield strength of about 50 percent, independent of temperature. Grain growth accounts for further changes. The yield strength sigma/sub y/ obeys the relationship sigma/sub y/ = sigma/sub 0/ + k/sub y/(anti d)/sup -1/2/ where sigma/sub 0/ and k/sub y/ are constants and anti d is the average grain diameter of the fully recrystallized matrix. Recrystallization and grain growth kinetics, respectively, satisfy the expressions f = 1 -- exp(--kt/sup n/) and anti d = Kt/sup m/ where f is the fraction recrystallized, t is time, k and K are parameters which increase with increasing temperature and m and n are constants. 13 figures (auth)

Effects of annealing on profiles of aluminum implanted in silicon carbide

The effects of isothermal annealing on the profiles of heavy (4×1016 Al+/cm2 at 60 keV) implantations of Al in SiC were investigated by means of the 27Al(p,γ)28Si nuclear resonance technique. Annealing at 1400 °C for 15 min resulted in the apparent outdiffusion of about 30% of the implanted Al, an accumulation of Al at the surface, and a residual peak at the depth of the as−implanted profile. Subsequent annealing showed continued apparent outdiffusion with the release of Al from trapping sites as the rate−limiting process.

`Aquoluminescence' from γ-irradiated crystals: effect of isothermal annealing

When γ-irradiated alkali halide crystals are dissolved in water a bluish glow extending into the ultraviolet occurs. This `aquoluminescence' has been used to study first-order rate constants for isothermal annealing processes and the energy levels of trapped electrons.