JOURNAL OF THE CHINESE CERAMIC SOCIETY

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1 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 ( ) Ag/DyBa 2 Cu 3 O 7 δ (Ag/Dy123) 10% ( )Ag/Dy Ag/Dy123 X X Ag Dy123 Dy123 (5% 10%)Ag/Dy %Ag/Dy mm 3 /(N m) Ag Ag TB34 A (2012) :59:12 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 , Jilin, China; 2. Province Key Laboratory of Material Tribology, Jiangsu University, Zhenjiang , 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 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, ) ( ) ( ) (1964 ) Received date: Revised date: First author: DONG Lirong (1964 ), female, Ph.D., Professor. dlr5640@163.com

2 [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 ) Dy % Dy 2 O 3 BaCO 3 CuO Dy Ba Cu 1:2:3 20 h h 3 Dy123 Ag ( 99.9%) 0 5% 10% 15% 20% Dy MPa φ 6 mm 10 mm h h Ag/Dy 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) N ( cm/s) Pa [17] (Hitachi S-570) X (PV-9900) 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/Dy 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 ,

3 Ag/DyBa 2 Cu 3 O 7 δ 1249 Ag Ag 2 10%Ag/Dy123 (SEM) (HRTEM) 2a Dy μm 900 Ag 960 Ag Dy123 2b 10%Ag/Dy123 HRTEM (110) 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 = 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 a 10%Ag/ Dy T T C 10%Ag/Dy , b 4 10%Ag/Dy123 SEM X (EDXA) 2a 3 5 μm 4a 10%Ag/Dy123 SEM 4b 10%Ag/Dy123 EDXA Ag/Dy123 Ag N Dy

4 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 N 13 cm/s 60 min Dy123 Ag 5% 10% 15% 20% Ag/Dy 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 = N, at room temperature. (5% 10%)Ag/Dy 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 N, 13 cm/s and 60 min, respectively.

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