JOURNAL OF THE CHINESE CERAMIC SOCIETY

2012 9 Ag 3 PO 4 /TiO 2 JOURNAL OF THE CHINESE CERAMIC SOCIETY 1247 Vol. 40 No. 9 September 2012 Ag/DyBa 2 Cu 3 O 7 δ 1 2 2 1 1 (1. 136000 2. 212013) Ag/DyBa 2 Cu 3 O 7 δ (Ag/Dy123) 10% ( )Ag/Dy123 0.20 Ag/Dy123 X X Ag Dy123 Dy123 (5% 10%)Ag/Dy123 0.25 5%Ag/Dy123 4.02 10 5 mm 3 /(N m) Ag Ag TB34 A 0454 5648(2012)09 1247 06 2012 07 25 8:59:12 http://www.cnki.net/kcms/detail/11.2310.tq.20120725.0859.002.html Tribological Properties of Ag/DyBa 2 Cu 3 O 7 δ Superconducting Ceramics DONG Lirong 1 LI Changsheng 2 TANG Hua 2 YU Wanqiu 1 HUA Zhong 1 (1. Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin, China; 2. Province Key Laboratory of Material Tribology, Jiangsu University, Zhenjiang 212013, Jiangsu, China) Abstract: The tribological properties of the Ag/DyBa 2 Cu 3 O 7 δ (Ag/Dy123) superconducting ceramics were investigated via a friction/wear tester from liquid nitrogen temperature to ambient temperature. The friction coefficient of 10% (in mass) Ag/Dy123 ceramics against stainless steel is < 0.2, and is stable when the temperature reduces to liquid nitrogen temperature. The microstructure and morphology of the Ag/Dy123 ceramics were investigated by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscope and energy dispersive X-ray analysis, respectively. The results show that the silver particles distribute in the Dy123 matrix, improving the toughness of Ag/Dy123 ceramics due to the formation of a soft silver film on the surface of Ag/Dy123 ceramics during friction process. Ag/Dy123 superconducting ceramics exhibited improved tribological properties at ambient temperature. The friction coefficient of 5% 10% Ag/Dy123 ceramics against stainless steel is 0.25, and the wear rate of 5%Ag/ Dy123 ceramics is 4.02 10 5 mm 3 /(N m). Key words: dysprosium barium copper oxygen; silver; superconducting ceramics; friction coefficient; wear rate Dayo [1 3] Pb Pb Persson [3] Popov [4] [5 6] +3 Y 3+ RBa 2 Cu 3 O 7 (R=La, Nd, Sm, Eu, Dy, ) 2012 03 19 2012 04 14 (201105083) (2011 158) (1964 ) Received date: 2012 03 19. Revised date: 2012 04 14. First author: DONG Lirong (1964 ), female, Ph.D., Professor. E-mail: dlr5640@163.com

1248 2012 [7 9] [10 11] [12] DyBa 2 Cu 3 O 7 δ (Dy123) 100 K [13] Ag [14 16] Ag Dy123 Ag Ag/Dy123 ( 196 ) 1 1.1 Dy123 99.9% Dy 2 O 3 BaCO 3 CuO Dy Ba Cu 1:2:3 20 h 920 10 h 3 Dy123 Ag ( 99.9%) 0 5% 10% 15% 20% Dy123 700 MPa φ 6 mm 10 mm 900 10 h 500 10 h Ag/Dy123 1.2 X (D/max 2500VB3+/PC) (JEM-2100HR) (Lake Shore SC20) (SFT-4000 ) 1% 196 ( ) 20 ( ) HRC62 (φ 60.5 mm 2.5 mm 0.8 μm) 12.05 16.3 N (2.6 5.2 7.8 10.4 13 cm/s) 5 10 3 Pa [17] (Hitachi S-570) X (PV-9900) 2 2.1 1 Ag Ag/Dy123 1 Ag DyBa 2 Cu 3 O 7 δ (Dy123) XRD Fig. 1 XRD patterns of Ag/Dy123 superconducting ceramics with different mass fraction Ag dosages X (XRD) 1 Dy123 Ag 2 Ag Ag XRD Dy123 Ag Ag Dy123 Ag/Dy123 [16] 2.2 Dy123 Ag/Dy123 ( 196 ) Dy123 Ag/Dy123 Meissner Dy123 Ag 10% 20% Ag/Dy123 177 181 184 Dy123 Ag 1 Ag/Dy123 1 Ag 1 Ag/Dy123 Vickers Tab1e 1 Density, Vickers hardness and porosity of Ag/Dy123 Sample No. Mass fraction Density/ Vickers hardness Porosity/% of Ag/% (g cm 3 ) H V /GPa 1 0 5.13 26.3 1.97 2 5 6.47 8.6 1.11 3 10 6.39 11.2 1.14 4 15 6,41 12.5 1.30 5 20 6.54 12.3 0.77

Ag/DyBa 2 Cu 3 O 7 δ 1249 Ag Ag 2 10%Ag/Dy123 (SEM) (HRTEM) 2a Dy123 3 5 μm 900 Ag 960 Ag Dy123 2b 10%Ag/Dy123 HRTEM (110) 0.273 8 nm Dy123 Ag Dy123 XRD 3 10%Ag/Dy123 (μ) (T) Fig. 3 Friction factor (μ) of 10%Ag/Dy123 superconducting ceramics and steel as function of test time and temperature (T) Load = 12.05 N; sliding velocity v = 2.6 cm/s. 2 10%Ag/Dy123 SEM HRTEM Fig. 2 SEM and HRTEM photographs of 10%Ag/Dy123 superconducting ceramics 2.3 2.3.1 3a 10%Ag/ Dy123 20 196 20 T T C 10%Ag/Dy123 0.30, 180 0.2 3b 4 10%Ag/Dy123 SEM X (EDXA) 2a 3 5 μm 4a 10%Ag/Dy123 SEM 4b 10%Ag/Dy123 EDXA 2.3.2 5 Ag/Dy123 Ag 12.05 N Dy123 0.35

1250 2012 6 μ Ag Fig. 6 Friction coefficient μ as function of Ag content and load v = 2.6 cm/s, at room temperature. 4 10%Ag/Dy123 SEM EDXA Fig. 4 SEM photograph and EDXA pattern of worn surface of 10%Ag/Dy123 superconducting ceramics 12.05 N 13 cm/s 60 min Dy123 Ag 5% 10% 15% 20% Ag/Dy123 3.04 10 4 4.02 10 5 4.07 10 5 8.11 10 5 4.98 10 5 mm 3 /(N m) ( 7) 15%Ag/Dy123 20%Ag/ Dy123 15%Ag/Dy123 SEM ( 8) Dy123 (5% 10%)Ag/Dy123 5 μ Ag Fig. 5 Friction factor μ as function of Ag content and v Load = 12.05 N, at room temperature. (5% 10%)Ag/Dy123 0.25 Ag/Dy123 6 Ag/Dy123 Ag 2.6 cm/s Ag 5% 0.25 Ag Ag/Dy123 Ag/Dy123 7 Ag/Dy123 Fig. 7 Wear rates of Ag/Dy123 superconducting ceramics Load, sliding velocity and test time are 12.05 N, 13 cm/s and 60 min, respectively.

Ag/DyBa 2 Cu 3 O 7 δ 1251 Ag Dy123 Ag Ag [18] 15%Ag/Dy123 Ag 2 10%Ag/Dy123 EDXA 2 Ag 10.70% 15.89% Ag Ag/Dy123 2 10%Ag/Dy123 EDXA Table 2 EDXA result of 10%Ag/Dy123 super-conducting ceramics before and after friction Test condition Mass fraction/% Ba Dy Ag Cu Before friction 34.79 28.68 10.70 25.83 After friction 36.76 23.10 15.89 24.25 3 1) Dy123 (5% 20%) Ag/Dy123 Ag Dy123 Ag Dy123 Ag 2) 10%Ag/Dy123 0.20 Dy123 3) Ag 5% 10% Ag/Dy123 Ag/Dy123 8 Ag/Dy123 SEM Fig. 8 SEM photographs of worn surfaces of Ag/Dy123 superconducting ceramics [1] DAYO A, ALNASRALLAH W, KRIM J. Superconductivity-dependent sliding friction [J]. Phys Rev Lett, 1998, 80(8): 1690 1693. [2] MASON B I, WINDER S M, KRIM J. On the current status of quartz crystal microbalance studies of superconductivity dependent sliding friction [J]. Tribol Lett, 2001,10(1 2): 59 65. [3] PERSSON B N J. Electronic friction on a superconductor surface [J]. Solid State Commun, 2000, 115: 145 148. [4] POPOV V L. Electronic and phononic friction of solids at low tem-

1252 2012 peratures [J]. Tribol Int, 2001, 34: 277 286. [5] DING Qiaodang, LI Changsheng, DONG Lirong. Preparation and properties of YBCO/Ag self-lubricating composites [J]. Wear, 2008, 265: 1136 1141. [6],,. YBa 2 Cu 3 O 7 δ [J]., 2008, 4: 345 350. DONG Lirong, LI Changsheng, HUA Minqi. Tribology (in Chinese), 2008, 4: 345 350. [7] MAEDA A, YABE T, UCHINOKURA K, et al. High temperature superconductivity at 90 K in orthorhombic LaBa 2 Cu 3 O y [J]. Jpn J Appl Phys, 1987, 26(8): 1368 1370. [8] LI S, HAYRI E A, RAMANUJACHARY K V, et al. Orthorhombic to tetragonal transition in R 1+x Ba 2 x Cu 3 O 7+δ (R = Nd, Sm and Eu)[J]. Phys Rev B, 1988, 38: 2450 2454. [9] TAKITA K, AKINAGA H, KATOH H. Superconductivity transition and crystal structure of the high T C superconductor DyBa 2 Cu 3 O y [J]. Jpn J Appl Phys, 1987, 26(6): 1023 1025. [10] KULEBA V I, OSTROVSKAYA YE L, PUSTOVALOV V V. Effect of superconducting transition on tribological properties of materials [J]. Tribol Int, 2001, 34: 237 246. [11] FANG Y, DANYLUK S. Coefficients of friction of YBCO-YBCO and YBCO-Ag ball-on-flat couples [J]. Mater Sci, 1993, 28: 5658 5662. [12],,,. [J]., 2009, 36(8): 1385 1390. DONG lirong, LI Changsheng, TANG Hua, et al. J Chin Ceram Soc. 2009, 36(8): 1385 1390. [13] KÔKI Takita, HIROYUKI Akinaga, HIDEO Katoh, et al. Superconductivity transition and crystal structure of the high T c and high H c2 superconductor DyBa 2 Cu 3 O 7 δ [J]. Jpn J Appl Phys, 1987, 26: 1023 1025. [14] FUJIMOTO H, SHIMADA H, YOSHIZAW S. Mechanical properties of DyBaCuO superconducting bulks [J]. Physica C, 2007, 463 465: 374 378. [15] FUJIMOTO H, SHIMADA H, YOSHIZAWA S. Preparation and properties of large single domain DyBaCuO superconductor [J]. Physica C, 2006, 445 448: 366 370. [16] FUJIMOTO H. Superconducting and mechanical properties of RE-Ba- Cu-O/Ag bulk superconductors [J]. IEEE Trans Appl Supercond, 2005, 15(2): 3098 3101. [17] BÜLENT Öztürk, FAZLI Arslan, SULTAN Öztürk. Hot wear properties of ceramic and basalt fiber reinforced hybrid friction materials [J]. Tribol Int, 2007, 40: 37 48. [18] JOO J, KIM J G, NAH W. Improvement of mechanical properties of YBCO-Ag composite superconductors made by mixing with metallic Ag powder and AgNO 3 solution [J]. Superconduct Sci Technol, 1998, 11(7): 645 649.