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Effect of tellurium and sulphur admixtures on crystallization kinetics of vitreous selenium
Vol. 39, No. 5 9.
ABSTRACTS OF ARTICLES TO BE PUBLISHED IN THE J. PHYS. CHEM. SOLIDS
VIBRATIONAL SPECTROSCOPY AT HIGH PRESSURES: PART 32. PRESSUREDEPENDENCIES OF THE RAMAN-ACTIVE MODES OF CdXa AND PbFX TYPE LAYER MATERIALS D.M. Adams and Tiong-Kie Tan, Department of Chemistry, University of Leicester, Leicester LEl 7RH, England.
The variation of Raman-active phonons of CdX,, (X = Cl, Br, I), and of PbFX, (X = Cl, Br), has been investigated to about 40 kbar. Rigid layer shear modes were found for CdBr, and CdIz and shown to have much greater Griineisen constants than intralayer modes. Received 28 October 1980 Revised 28 January 1981 10.
CRYSTALLIZATION KINETICS OF y-IRRADIATED VITREOUS SELENIUM W. Swigtkowski, Department of Radiation Technique, Polytechnical University, 90-924 MdB, Poland.
At the temperature of 9O.O”C the crystallization rate of -y-irradiated (O-l 54.5 Mrad) vitreous selenium has been studied by the calorimetric method. The obtained results satisfy the Avrami’s equation x = 1 - exp (- LcKrrZ). It was found that radiation induced changes of vitreous selenium structure bring about the decrease of the exponent z and the increase of the value LcK,. The relationship between the above results and structural changes of vitreous selenium was discussed. Received 27 May 1980
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EFFECT OF TELLURIUM AND SULPHUR ADMIXTURES ON CRYSTALLIZATION KINETICS OF VITREOUS SELENIUM W. Swiatkowski, Department of Radiation Technique, Polytechnical University, 90-924 L&b!; Poland.
The influence of tellurium (up to 6 at.%) and sulphur (up to 2 at.%) admixtures on the rate and on the activation energy EKr of vitreous selenium crystallization was investigated by means of calorimetric method. The results satisfy the Avrami’s equation x = 1 - exp (- LcKrY). The exponent z and the product zE,, are increased due to addition of tellurium admixtures, while the value LcKr is decreased. The admixtures of sulphur decrease the exponent z, but have not any influence on the values LcKr and zE,,. Probably the tellurium admixtures increase the rate of the crystallite growth and the number of the crystallization centres, what accelerates the process. But at the same time, formation of the stable nucleus is prolonged. Sulphur admixtures do not change the contents of the small rings and of the hexagonal regions in vitreous selenium. The produce defects in the chain structure, what retards the crystallization. Received 27 May 1980
ABSTRACTS OF ARTICLES TO BE PUBLISHED IN THE J. PHYS. CHEM. SOLIDS
VIBRATIONAL SPECTROSCOPY AT HIGH PRESSURES: PART 32. PRESSUREDEPENDENCIES OF THE RAMAN-ACTIVE MODES OF CdXa AND PbFX TYPE LAYER MATERIALS D.M. Adams and Tiong-Kie Tan, Department of Chemistry, University of Leicester, Leicester LEl 7RH, England.
The variation of Raman-active phonons of CdX,, (X = Cl, Br, I), and of PbFX, (X = Cl, Br), has been investigated to about 40 kbar. Rigid layer shear modes were found for CdBr, and CdIz and shown to have much greater Griineisen constants than intralayer modes. Received 28 October 1980 Revised 28 January 1981 10.
CRYSTALLIZATION KINETICS OF y-IRRADIATED VITREOUS SELENIUM W. Swigtkowski, Department of Radiation Technique, Polytechnical University, 90-924 MdB, Poland.
At the temperature of 9O.O”C the crystallization rate of -y-irradiated (O-l 54.5 Mrad) vitreous selenium has been studied by the calorimetric method. The obtained results satisfy the Avrami’s equation x = 1 - exp (- LcKrrZ). It was found that radiation induced changes of vitreous selenium structure bring about the decrease of the exponent z and the increase of the value LcK,. The relationship between the above results and structural changes of vitreous selenium was discussed. Received 27 May 1980
11.
“’
ill
EFFECT OF TELLURIUM AND SULPHUR ADMIXTURES ON CRYSTALLIZATION KINETICS OF VITREOUS SELENIUM W. Swiatkowski, Department of Radiation Technique, Polytechnical University, 90-924 L&b!; Poland.
The influence of tellurium (up to 6 at.%) and sulphur (up to 2 at.%) admixtures on the rate and on the activation energy EKr of vitreous selenium crystallization was investigated by means of calorimetric method. The results satisfy the Avrami’s equation x = 1 - exp (- LcKrY). The exponent z and the product zE,, are increased due to addition of tellurium admixtures, while the value LcKr is decreased. The admixtures of sulphur decrease the exponent z, but have not any influence on the values LcKr and zE,,. Probably the tellurium admixtures increase the rate of the crystallite growth and the number of the crystallization centres, what accelerates the process. But at the same time, formation of the stable nucleus is prolonged. Sulphur admixtures do not change the contents of the small rings and of the hexagonal regions in vitreous selenium. The produce defects in the chain structure, what retards the crystallization. Received 27 May 1980