Kinetics of the C49 TO C54 Phase Transformation in TiSi2 thin Films on Deep-Sub-Micron Lines

1995 ◽  
Vol 402 ◽  
Author(s):  
J. A. Kittl ◽  
D. A. Prinslow ◽  
P. P Apte ◽  
M. F. Pas
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Phase Transformation ◽  
Full Time ◽  
Two Dimensional ◽  
One Dimensional ◽  
Grain Sizes ◽  
Nucleation Sites ◽  
Dimensional Growth ◽  
Kinetics Of

AbstractThe kinetics of the TiSi2 C49 to C54 phase transformation in thin films on patterned deepsub- micron lines, were studied to obtain the full time, temperature and linewidth dependence of the fraction transformed during rapid thermal annealing. A Johnson-Mehl-Avrami kinetic analysis was performed, obtaining Avrami exponents of 0.8±0.2 for all sub-micron lines and 1. 9±0.2 for a 40 μm side square structure, indicating heterogeneous nucleation followed by one dimensional growth for the narrow lines, and two dimensional growth for the square structure. The activation energy, of 3.9 eV, was independent of linewidth in the sub-micron range. Transformation times increased dramatically for decreasing linewidth, as the linewidth approached the grain size of the starting C49 phase. A kinetic model based on the density of nucleation sites as a function of linewidth and C49 grain size is proposed and shown to fit the data, for samples with two different C49 grain sizes.

scholarly journals Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Wenjun Song ◽  
Min Lei ◽  
Mingpan Wan ◽  
Chaowen Huang
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Austenite Formation ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Continuous Cooling ◽  
The Matrix ◽  
Dimensional Growth ◽  
Kinetics Of

In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.

Optical Properties and Phase Transformation Kinetics of Ge-Sb-Te-(N) Alloy Thin Films Investigated by Ellipsometry

2003 ◽  
Vol 803 ◽  
Author(s):  
Sang Youl Kim
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Optical Properties ◽  
Phase Change ◽  
Crystallization Behavior ◽  
Ex Situ ◽  
Recent Analysis ◽  
Avrami Equation ◽  
Step Process ◽  
Kinetics Of

ABSTRACTThe recent research works of optical properties and crystallization kinetics of phase change Ge-Sb-Te-(N) alloy by using ellipsometry are reviewed.The complex refractive index spectra of phase-change Ge2Sb2+xTe5 thin films and those of the nitrogen Ge2Sb2Te5 thin films have been determined.The crystallization behavior of amorphous Ge2Sb2Te5 thin films investigated by in situ ellipsometry revealed that the crystallization process of Ge2Sb2Te5 near 140°C is a two-step process. The kinetic exponent of the Johnson-Mehl-Avrami equation was about 4.4 for the first stage and 1.1 for the second stage. Ex situ study confirmed the cascaded crystallization behavior of phase-change Ge2Sb2Te5 films.A passive type single wavelength ellipsometer adopting a DOAP (division-of-amplitude photopolarimeter) configuration with nanosecond time resolution is developed to monitor the phase transformation of Ge2Sb2Te5 caused by a high power nanosecond laser pulse in real time. The two-step process - the fast nucleation-dominant stage followed by the slow anomalous grain growth stage is confirmed.Based on the recent analysis of the ellipsometric isotherm at moderately elevated temperature, we found for the first time that the fast nucleation dominant crystallization of Ge2Sb2Te 5 can be better explained by a modified JMA equation that illustrates the nucleation dominated process where the creation rate of a new nucleus is proportional to the density of preexisting nuclei and growth rate is negligible.

Polycrystalline Si Films Fabricated by Low Temperature Selective Nucleation and Solid Phase Epitaxy Process

1997 ◽  
Vol 485 ◽  
Author(s):  
Claudine M. Chen ◽  
Harry A. Atwater
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Crystal Growth ◽  
Incubation Time ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Grain Sizes ◽  
Random Nucleation ◽  
Nucleation Sites ◽  
Si Films

AbstractWith a selective nucleation and solid phase epitaxy (SNSPE) process, grain sizes of 10 μm have been achieved to date at 620°C in 100 nrm thick silicon films on amorphous SiO2, with potential for greater grain sizes. Selective nucleation occurs via a thin film reaction between a patterned array of 20 rnm thick indium islands which act as heterogeneous nucleation sites on the amorphous silicon starting material. Crystal growth proceeds by lateral solid phase epitaxy from the nucleation sites, during the incubation time for random nucleation. The largest achievable grain size by SNSPE is thus approximately the product of the incubation time and the solid phase epitaxy rate. Electronic dopants, such as B, P, and Al, are found to enhance the solid phase epitaxy rate and affect the nucleation rate.

Preparation and Photoelectrochemical Properties of SrTiO3 Thin Films on Nickel Substrate by Hydrothermal Method

2007 ◽  
Vol 121-123 ◽  
pp. 1297-1300
Author(s):  
G.T. Wang ◽  
J.P. Tu ◽  
W.K. Zhang ◽  
X.L. Wang ◽  
H. Huang
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Saturated Vapor ◽  
Photoelectrochemical Properties ◽  
Vapor Pressures ◽  
Nickel Substrate ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Ni Substrate ◽  
Grain Sizes

Well-crystallized nanopolycrystalline thin films of cubic strontium titanate, SrTiO3, have been prepared on the TiNi-deposited Ni substrate in Sr(OH)2 aqueous solutions at temperatures between 130 and 200°C under saturated vapor pressures. The microstructure and morphology of the films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photoelectrochemical properties of SrTiO3 thin films on TiNi-deposited Ni substrate were investigated on a three-electrode assembly. The grain sizes increased from 30 nm to 300 nm and the relative crystal intensity in XRD pattern increased with the reaction temperature. Its photocurrent increasesdfirst with the grain size, then decreased. When the grain size of the film is about 200 nm, the photocurrent is highest.

Effects of Sputtering Conditions on Texture, Microstructure and Magnetic Properties of the CoCrPt/NiAl Thin Films

1998 ◽  
Vol 517 ◽  
Author(s):  
Y.-N. Hsu ◽  
D. E. Laughlin ◽  
D. N. Lambeth
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Magnetic Properties ◽  
Optimum Pressure ◽  
Grain Sizes ◽  
Maximum Value ◽  
Sputtering Power ◽  
Sputtering Pressure ◽  
The Relationship ◽  
Microstructure And Magnetic Properties

AbstractThe effects of sputtering argon pressures and sputtering power on the microstructure, texture and magnetic properties of NiAI underlayers on CoCrPt films were investigated. In this paper, the relationship between the sputtering conditions, microstructure, crystallographic texture and magnetic properties of these thin films will be discussed. By controlling the sputtering pressure and sputtering power, the texture and microstructure of NiAI underlayers were found to vary. This in turn was found to influence the magnetic properties of CoCrPt thin films. It was found that 10 mtorr is the optimum pressure to deposit the NiAl thin films to obtain the best magnetic properties for our system. At this argon pressure, the coercivity reached a maximum value because of the strongest CoCrPt (1010) texture and smallest grain size. At lower argon pressures (< 10 mtorr), NiAI tended to have a (110) texture reducing the CoCrPt (1010) texture, which in turn reduced the CoCrPt coercivity and S*. Also, high NiAl deposition pressures (>30 mtorr) yielded larger grains and a weaker CoCrPt (1010) texture, thereby decreasing the coercivity of the CoCrPt films. Increasing the sputtering power has been found to increase the CoCrPt coercivity and S* value. However, the grain sizes of the CoCrPt/NiAl thin films deposited at higher sputtering power were larger than those obtained at lower sputtering power.

Enhancement of Aurivillius Phase Formation Kinetics in SBT Thin Films using Nanoparticle Seeding

2003 ◽  
Vol 784 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwak ◽  
Se-Yon Jung ◽  
Seung-Joon Hwang
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Phase Transformation ◽  
Phase Formation ◽  
X Ray Diffraction ◽  
Aurivillius Phase ◽  
X Ray ◽  
Si Substrates ◽  
Formation Kinetics ◽  
Kinetics Of

ABSTRACTPt/Ti/SiO2/Si substrates seeded by SBT nanoparticles (∼60–80 nm) were used to enhance the phase formation kinetics of Sr0.7Bi2.4Ta2O9 (SBT) thin films. The volume fractions of Aurivillius phase formation obtained through quantitative x-ray diffraction (Q-XRD) analyses showed highly enhanced kinetics in seeded SBT thin films. The Avrami exponents were determined as ∼1.4 and ∼0.9 for unseeded and seeded SBT films, respectively, which reveals different nucleation modes. By using Arrhenius–type plots the activation energy values for the phase transformation of unseeded and seeded SBT thin films were determined to be ∼264 and ∼168 kJ/mol, respectively. This gives a key reason to the enhanced kinetics in seeded films. Microstructural analyses on unseeded SBT thin films showed formation of randomly oriented needle-like crystals, while those on seeded ones showed formation of domains comprised of directionally grown worm-like crystals.

Effect of Low-Temperature Aging on Thermally-Induced Phase Transformation of NiTi Wire with a Wide Range of Grain Sizes

2021 ◽  
Vol 1042 ◽  
pp. 9-16
Author(s):  
Zhi Hao Zhao ◽  
Jian Ping Lin ◽  
Jun Ying Min ◽  
Yong Hou ◽  
Bo Sun
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Low Temperature ◽  
Thermally Induced ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Wide Range ◽  
Low Temperature Aging ◽  
Niti Wires ◽  
Temperature Aging

Thermally-induced phase transformation (PT) is of significance and value to the application of NiTi alloy components. Low-temperature aging (LTA) treatment was used to alter PT characteristics of NiTi alloys avoiding undesirable grain growth. Effect of LTA on PT of NiTi wires with a wide range of grain sizes from 34 nm to 8021 nm was investigated in this study. As the average grain size varies from 34 to 217 nm, the temperature of the B2↔R transformation increase as a result of LTA, and the increasing effect is more obvious at a larger grain size. For NiTi alloys with average grain sizes ranging from 523 to 1106 nm, transformation sequence changes from B2↔B19' to B2↔R due to LTA. For the sample with an average grain size of 2190 nm, the B2↔B19' transformation is replaced by B2↔R←B19' after LTA. When the average grain size is larger than 2190 nm, transformation sequence changes from B2↔B19' to B2↔R↔B19' after LTA. Transmission emission microscope observations reveal that the above-mentioned PT behavior correlates with the coupled effect of grain size and precipitation. The precipitation of Ni4Ti3 in the grains with a size smaller than ~150 nm is inhibited after LTA, the temperature of B2→R of samples with average GS smaller than ~150 nm still is elevated due to the inhomogeneous grain size of NiTi wires.

Kinetics and mechanism of anatase-to-rutile phase transformation in the presence of borosilicate glass

1999 ◽  
Vol 14 (7) ◽  
pp. 2922-2928 ◽  
Author(s):  
Jau-Ho Jean ◽  
Shih-Chun Lin
Keyword(s):  
Phase Transformation ◽  
Borosilicate Glass ◽  
Rutile Phase ◽  
Kinetics And Mechanism ◽  
Avrami Equation ◽  
Two Dimensional ◽  
Transformation Kinetics ◽  
Controlling Mechanism ◽  
Particle Coalescence ◽  
Kinetics Of

The effects of borosilicate glass (BSG) on the kinetics and mechanism of anataseto- rutile phase transformation have been investigated. The displacive anatase-to-rutile phase transformation kinetics of TiO2 were greatly enhanced in the presence of BSG. The transformation kinetics followed the Avrami equation, and the results showed an apparent activation energy of 260–370 kJ/mol, which was close to the bond strength of Ti–O, suggesting a reaction-controlling mechanism. The values of the Avrami exponent were in the range of 1.4–2.3, which could be interpreted as two-dimensional reaction-controlled growth at zero nucleation rate. The rutile particles obtained by the phase transformation were always much larger than the starting anatase powders, which was explained by a mechanism of phase-transformation–induced particle coalescence.

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