Longitudinal and shear ultrasonic velocities were measured in different compositions of the glass system Nd203(x)CuO(35-x)P205(65) at temperature range between 270 K and 323 K. From the transit time data and density, we found that all the elastic properties for these glasses decrease as the Nd203 content increase, which indicates a weakening ofthe binding energy in the network

Budi, Agus Setyo

Russin, Rosli

Sahar, Md. Rahim

English

Universiti Teknologi Malaysia Institutional Repository

1. Fiz. UTM, 9.1 (2003) 38 - 47Study of Nd20 3-CuO-P20s glass system by elastic propertiesAgus Setyo Budi, Rosli Russin and Md. Rahim Saharlabatan Fizik, Fakulti Sains, Universiti Teknologi malaysia, 81310 Skudai, lohorManuscript receivedManuscnpt revised07 Jan. 200321 Sept 2003Abstrac: Longitudinal and shear ultrasonic velocities were measured in differentcompositions of the glass :;ystem Nd203(xrCuO(35-xrP205(65) at temperature range between270 K and 323 K. From the transit time data and density, we found that all the elasticproperties for these glasses decrease as the Nd20 3 content increase, which indicates aweakening ofthe binding energy in the network.Introduction: P20S glasses have several advantages over conventional silicate and borateglasses due to their superior physical properties such as high thermal expansion coefficients,low melting and softening temperatures and high ultraviolet transmission [1-3]. However thepoor chemical durability, high hygroscopic and volatile nature of phosphate glassesprevented them from replacing the conventional glasses in a wide range of technologicalapplications. In recent years there has been enormous amount of research on improving thephysical properties and the chemical durability of phosphate glasses by introducing anumber of glass formers and modifiers, such as Ah03, Mo03, As20 3, Sb20 3, Ta20s, etc., intoglass network [4-51.The transition metal oxides glasses are those in which the transition metal oxide is a majorconstituent and they are typical of the charge transfer or mixed valence type ofsemiconductors. Glasses containing rare-earths ions may also exhibit different valency statesand may contribute to electronic conduction. Most research has been carried out ontransition metal oxide glasses with added lanthanides from either end of the rare-earth series,e.g. cerium with two 4f electrons, or praseodymium with three 4f electrons, at one end of theseries, and erbium with eleven 4f electrons, or lutetium with fourteen 4f electrons, at the0128-864412003 - lahatan Fizik UTM. All right reserved 38J Fiz Urlvl, 9.1 (2003) 38 - 47other end of the series, in order to investigate how the addition of any of these might controlthe properties of the glass [6]. Neodymium lies in the lanthanide series with four 4felectrons. The doping of Nd to the copper phosphate glass systems is therefore aninteresting investigation to be carried out. lt was predicted that perhaps praseodymium withthree ·H electrons being ore stable. and considerably shielded by outer electron shells mightresult in behavior more like that crystal with sharp optical absorption edge. but have littleadditional effect on such properties as the electrical conductivity, etc. Although conductivityand optical absorption data [7-8] on some binary and ternary copper phosphate glasses areavailable. no ultrasonic measurement on copper phosphate glass containing the rare-earthneodymium has so far been reported. So it is instructive to undertake the elastic properties ofthese glasses by ultrasonic technique.Sample preparation : Glasses of composition Nd20 3(x)-CuO(35-x)-P205(65) were prepared,where the compositions are given in mol % and 0 ::::; x::::; 10 mol %. The oxide componentswere carefully weighed out and mixed in silica crucible of 80 cm3 capacity. To react theconstituents. the mixture of neodymium oxide, copper oxide and phosphorus pentoxide inthe crucible was heated in an electrical furnace at 350°C for Ih, and then melted in anotherfurnace at 1200 °c . To ensure proper mixing and homogeneity, the molten liquid wasshaken frequently and vigorously. After being checked, the melt was cast by pouring as fastas possible into a hot steel split mould to quench to form a glass. The glass was immediatelytransferred to an annealing furnace at 350°C where it was kept for 3 h to relieve any residualstress Ihat could cause embrittlement. At the end of this annealing process, the furnace wasswitched off and the glass left to cool down to the room temperature gradually by controlledthermal treatment at cooling rate of 0.50C/min. The samples were selectively cut, ground,and polished. After preparation, samples were stored in plastic containers in a dessicator. Asimple Archimedes process using toluene as the immersion liquid measured the density ofthe glass samples. The measurement of velocity of longitudinal and shear ultrasonic wavewere performed at frequencies 5 and 10 tv1Hz and within the temperature range 270 K - 323K. The contribution to the loss due to the bonding agent between the transducer and thesample was neglected. because its typical thickness was less than 10 ~mK0128-864412003 - labatan Fizik UTM All right reserved 391. Fiz. UTM. 9.1 (2003) 38 - 47Result and Discussion: The density ofxNd20 3 - (35-x)CuO - 65PzOs glasses is shown inthe Table I and the density variation with Nd20 3 content is shown in Figure 1. The resultsshow that the density iucreases with the increase of Ndz0 3 content 2.725 g/cm3 for x == 0%and 2.86 I g/cm3 for x == 10%. This may due to the network modifying ions tend to occupyinterstitial sites within the highly open glass network.The temperature dependence of longitudinal and shear ultrasonic velocities for differentsamples is shown in Figure 2(a) and Figure 2(b). 11 is observed that for both polarizations ofthe sound waves, the ultrasonic velocity decreases monotonically with increasingtemperature for all the samples. From the longitudinal, shear velocities of the sound, and thedensity data, the value of elastic moduli (Lame's constants, Ie, ~I Bulk modulus, B, Young'smodulus, E ) at different temperatures are obtained using the relevant relation given in ourearlier works [9].Sample No. Density (g/cm3)S6 2.725S7 2.759Sg 2.777S9 2.808SIO 2.831Sll 2.861The decrease of sound velocity with increasing temperature in the present case is attributedto a thermally activated relaxation process proposed by Anderson and Bommel fIOl Thepresence of such relaxation process has its origin in the disorder inherent in amorphousmaterials. The relaxation process can be ascribed to a particle moving in a double-wellpotential corresponding to two structure in amorphous network. The relaxation time, -r(V)depends on temperature, T and activation energy, V, according to Arrhenius relation0128-8644/2003 - Jabatan hzik UTM. All right reserved 401. Fiz. UTM. 9.1 (2003) 38 - 47't(V) = 'to eVIkT where 'to is constant; the activation energy, V, will have a distributionbecause of the amorpholls phase of substance. The variation of ~ V , of sound velocity dueto such a relaxation process is given by formula [ 11].2.9 ., ,2.75•••••..--...("')E 2.85u-0>:; 2.8encQ.)o,-"-'-'--'_._..iII[[II12106mole %422.7 -1-----,-----r---.......,...----r---...,......---ioFigure 1 : Density of the glass for various Nd20 3 contents (mole %)0128-8644/2003 - Jabatan Fizik UTM. All right reserved 411. Flz l'TM, 9.1 (2003) 38 - 47••••••••• ••1400en 1300:§.>-13 1200.Qw 1100><IlK~ 1000-0.2'0, 900c0-'800260 280 300 320 340• x = 0.x=2... x=4x x~S* x~ 8• x= 10Temperature (K)(a)700'"w.c(J)600500• x~c 0• x= 2... x~4x x=6* x= 8• x = 10330320310300290280400 +----~----~--~---K__--~--__i270Tef11)erature (K)(b)Figure 2. The temperature dependence of (a) the longitudinal velocity, (b) shear velocity ofvarious mol % Nd20 3 in xNd20 3 - (35-x)CuO - 65P20S glassesWe also showed that in glass induce more significant changes in longitudinal velocity ifcompared with shear velocity. From Figure 3, it is observed that the value of elastic constantC44 is smaller than the value of elastic constant Cll. Apparently the characters ofthe glass so0128-8644/2003 - Jabatan Fizik UTM. All right reserved 42J. Fiz. UTM, 9.1 (2003) 38 - 47produced are easy to bend but difficult to compress. From the graph, the elastic constant C j Jand C44 decrease with increases in temperature.A similar trend as the elastic constant is observed in the case of bulk modulus. Figure 4(b)shows the variation of bulk modulus with mol % of Nd20 3 in xNd20 3 - (Js-x)CuO -65P20, glasses. This shows that the elasticity of the glass increases with the increase inmole % of Nd20 3- It is apparently that the stiffness of the ternary glasses decreases with theincrease of content of Nd20 3 .Sample with higher Nd20 3 has a lower value of bulk modulus. The bulk modulus B and theelastic constant (C II and C44) ofthe PbO phosphate glass are 27, 47 and 15 Gpa respectively[) 2J. Comparison of these data with those of our lernary neodymium phosphate glassesshows that the 'values of elastic modulus is much higher. but those of binary neodymiumphosphate glasses shows that the values of elastic modulus is lower. This might be due to theability of the atoms to maintain their original neighbors, thus the interatomic spacing has notbeen altered.From Figure 5. the Young's modulus shows the ability of the glass with higher Nd20 3 toafford the exerted force per unit area or experience stress is stronger. According to Cahn eta1. [13], the glass with high Young's modulus should contain components with highdissociation energies and high package densities but small molecular weights.0128-8644/2003 - Jabatan Fizik UTM. All right reserved 431. Fiz. UTM, 9.1 (2003) 38 - 47-35 ........... --- ........ ......... __ ...................•.. ...........................................................................................C'I:Ia.C.9- 3(/)Q)• • • • •(/) • • • • • Cll(/) •Q) 2.5c:It::.;:;(/) 2(,):.;;(/)C'I:I 1.5QiI..Q)'E0'"0 IIlIl I1iiI m m m 00 I1iiI I1iiI C44c:jm ili1 I1IIiI0 0.5uQ)CJ)0270 280 290 300 310 320 330Temperature (K)Figure 3 : The temperature dependences of the second order elastic stiffnesses Cll and C44of 8 mol % Nd20 3U128-8644/2()()3 - }abatan Fizik UTM. All right reserved 44J. Fiz. UTM, 91 (2003) 38 - 47iii 45Q.~'":::I"3"o 3.5:EIII"r:»c::::Io>- 2.5%_•..:>t\o- ...._•• ~~ ............ 'Ill"--D-~"~D-D--1fl- _.•. , __~K_~K-» ..--,·_lQ>·······1lC·.... -. .. 4C• x ~ 0Kx~O... x =4X x ~ 6* x~ 8• x = 10270 280 29.0 300 31Cl 320 3.30Temperature (K)(a)353........_ ..-., --.- >---+.- --+--..•15• x = 0• x ~O.A. x . 4X x~ 6* x = I':• x = 10.> *'.- *-..-r. ~ ~ ,.,. ···.<'·· .. · .. ..,. " t·...- _ - ---.2III 25::>"3"0~=::>ell27Cl 280 290 300 310 320 330Temperature (K)(b)Figure 4 : The temperature dependences of (a) Young's modulus, (b) the bulk modulus, ofvarious mol% Nd20 30128-8644/2003 - }abatan Fizik UI'M. All right reserved 451. Fiz. UTM, 9.1 (2003) 38 - 473.54.535_ 3(llQ~ORI/)::l"5 2"Co~1R.1/)C'1: 1::lo>-05250.50+--------.-----,-------,-----..--------,------+0o 10 12Mole %Figure 5: Young's modulus and Bulk modulus versus mole % of Nd20 3Conclusions: The variations of ultrasonic wave velocity and hence elastic constant, bulkmodulus, Young's modulus and Poisson's ratio for xNd20r(35-x)CuO-65P20 s glasses withtemperature has been interpreted in term of thermally activated relaxation process.Acknowledgements: One of the authors Mr. Agus Setyo Budi wishes to thank the IRPA(vot no. 72153) for research facility and for the provision of studentship (ASB). The authorsexpress their sincere thanks to MrJaafar Raji and MrJohari Zainudin for assistance inobtaining the data.References[1] P Subbalakshmi, N. Veeraiah , lNon Cryst. Solids 298 (2002) 89-98U128-8644/2UU3 - Jabatan Fizik UTM. All right resenJed 461. Fiz. UTM. 9.1 (2003) 38 - 47[2] M.D. Ingram, Phys. Chern. Glasses 28 (1987) 215.[3] W. matz, D. Stachel, J.Non Cryst. Solids 101 (1988) 80[4] A. Mogus-Milankovic, D.E. Day, et aI., J.Non Cryst. Solids 263 & 264 (2000) 299[5] C.T. Chiao BVR. Chowdari, K.L. Tan, 1. Mater. Sci. 28 (1993) 3594[6] 1.M. Arzeian, c.A. Hogarth., 1. Mater. Sci. 26 (1991) 5353-5366[7] M.A. Hassan, CA Hogarth, and G.R. Moridi., Phys. Stat.sol. (a) 101, 537 (1987)[8J M.N. Khan, M.M. Ahmed, and c.A. Hogarth, 1. Mater. Sci. 20 (1985) 2207-2214.[9] S. Mukherjee. C. basu and U.S. Ghosh., J.Non Cryst. Solids 144 (1992) 159-168.[lOJ Anderson, O.L. and Bommel, RE., (1955). "Elastic properties and thermal expansionof cerium methaphosphate glasses". J. Am. Ceram. Soc. 38, 125.[11] 1. JackIe, L. Piche, and S. Hunklinger., J.Non Cryst. Solids 20 (1976) 365.[12] Paul, A., Ghosh, U.S., and Tripodo, G. (1997). "Ultrasonic velocity and attenuation inPb-Phosphate glass." J. Non Cryst. Solids. 221, 265 - 273.[13JCahn, R. W., Hassan, P. and Kramer, E.J., (1991). "Glasses and Amorphous Materials",Germany: VCH Pub.0128-8644/2003 -Jabatan Fizik UTM. 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Study of Nd203-CuO-P205 glass system by elastic properties

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Study of Nd203-CuO-P205 glass system by elastic properties

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