Material Specification for Bi:2212; [Bi-Sr-Ca-Cu-O]
Process: Solid State Reaction
Notes: "The 2212 powder was synthesized from a mixture of Bi2O3, SrCO3, CaCO3 and CuO. The actual composition was Bi2Sr1.7CaCu2Ox, which yields 2212 of good phase purity. The powders were ball-milled for 18-24 h in polyethylene jars containing methanol and ZrO2 grinding media. The milled powders were pan-dried, ground lightly with an agate mortar and pestle, and heated in air for 48-72 h at 815-820 °C. The resulting powder was ground in a tungsten carbide rotary mill... The 2212 powders were processed into bulk forms by hot isostatic pressing (HIP) or sinter forging. The HIPing was conducted for 2 h in an inert atmosphere at 105 MPa and (about) 825 °C. Large 3-4 mm thick discs were pressed, and several test bars were cut from each with a slow-speed diamond-blade saw. The sinter forging of bar-shaped specimens was conducted in air at 850 °C under rates of compression of 0.01-0.005 mm min-1. The final stress on the specimens was (about) 6 MPa... All of the specimens were polished prior to being tested."
Formula: Bi2Sr2CaCu2Ox
Informal Name: Bi:2212
Chemical Family: Bi-Sr-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Flexural Strength for Bi:2212; [Bi-Sr-Ca-Cu-O]
| Flexural Strength (MPa) |
| 90 |
Measurement Method: Four-point bend
"Some of the bars were also tested in the unnotched condition in four-point bending to determine strength." No additional measurement details were noted.
Cautions: Unevaluated Data
Hardness for Bi:2212; [Bi-Sr-Ca-Cu-O]
| Processing Condition () |
Hardness (GPa) |
| HIP |
0.76 ± 0.08 |
| Forge |
0.66 ± 0.07 |
Measurement Method: Vickers hardness
"Vickers hardnesses were measured on the top and side faces of the HIPed and sinter-forged samples. A load of 5 kg or 10 kg and a time of 10 s were used."
Cautions: Evaluated Data
Fracture Toughness for Bi:2212; [Bi-Sr-Ca-Cu-O]
| Processing Condition () |
Specimen Orientation () |
Fracture Toughness (MPa·m1/2) |
| HIP |
A |
3.2 ± 0.4 |
| HIP |
B |
3.9 ± 0.5 |
| Forge |
A |
2.7 ± 0.3 |
| Forge |
B |
3.2 ± 0.4 |
Measurement Method: Single-edge notched-beam
"Fracture toughness values were determined by the single-edge notched beam method. The test bars were loaded in three-point bending at a rate of 1.27 mm min
-1. K
IC was calculated from
K
Ic = 3 PLYC
0.5/BW
2
where P is the load at fracture, L is the support span (14-19 mm for these tests), Y is a constant related to the specimen geometry, C is the notch depth, B is the specimen width and W is the specimen height.
... Fracture toughness was measured in two orientations":
(A) with the notch cut perpendicular to the pressing direction, and
(B) with the notch parallel to the pressing direction."
Cautions: Evaluated Data
Sound Velocity for Bi:2212; [Bi-Sr-Ca-Cu-O]
| Processing Condition () |
Mode () |
Direction () |
Sound Velocity (km/s) |
| Forge |
Longitudinal |
c |
2.464 |
| Forge |
Longitudinal |
a/b(1) |
3.986 |
| Forge |
Longitudinal |
a/b(2) |
4.005 |
| Forge |
Shear |
c |
1.710 |
| Forge |
Shear |
a(1) |
2.422 |
| Forge |
Shear |
b(1) |
1.699 |
| Forge |
Shear |
a(2) |
2.399 |
| Forge |
Shear |
b(2) |
1.622 |
| HIP |
Longitudinal |
c |
3.330 |
| HIP |
Longitudinal |
a/b(1) |
4.024 |
| HIP |
Longitudinal |
a/b(2) |
4.022 |
| HIP |
Shear |
c |
1.968 |
| HIP |
Shear |
a(1) |
2.311 |
| HIP |
Shear |
b(1) |
1.956 |
| HIP |
Shear |
a(2) |
2.312 |
| HIP |
Shear |
b(2) |
1.981 |
Measurement Method: Ultrasonic pulse-echo
"The longitudinal and transverse velocities of sound were measured... Propagation directions were parallel and perpendicular to the preferred texture direction. For measurements of transverse velocity, the polarization of the shear wave was varied... The longitudinal velocity of sound was measured with an Aerotech Alpha 15 MHz transducer with a buffer rod, while the transverse velocity was measured with a Panametrics 5 MHz model V156 normal-incidence shear wave transducer (without a buffer). Standard pulse-echo methods were employed with a Panametrics model 5600 pulser receiver and LeCroy model 9400 oscilloscope. All samples were polished to provide smooth parallel surfaces. The acoustic path lengths ranged from 2 mm to 7.5 mm."
Cautions: Evaluated Data
"Notation: c corresponds to the direction of preferred orientation (001), which is also parallel to the SF pressing direction or perpendicular to the disc surface in HIPed samples, a/b refers to the direction perpendicular to c. ... When the transverse velocity is dependent on polarization, the slower velocity occurs when the polarization is in the direction of preferred orientation."
