TY - JOUR
T1 - Effect of alumina composition and surface integrity in alumina/epoxy composites on the ultrasonic attenuation properties
AU - Cho, Eikhyun
AU - Park, Gwanwoo
AU - Lee, Jae Wan
AU - Cho, Sung Min
AU - Kim, Taekyung
AU - Kim, Joongeok
AU - Choi, Wonjoon
AU - Ohm, Won Suk
AU - Kang, Shinill
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government ( MSIP ) (No. 2015R1A5A1037668).
PY - 2016/3/1
Y1 - 2016/3/1
N2 - We report a method of fabricating backing blocks for ultrasonic imaging transducers, using alumina/epoxy composites. Backing blocks contain scatterers such as alumina particles interspersed in the epoxy matrix for the effective scattering and attenuation of ultrasound. Here, the surface integrity can be an issue, where the composite material may be damaged during machining because of differences in strength, hardness and brittleness of the hard alumina particles and the soft epoxy matrix. Poor surface integrity results in the formation of air cavities between the backing block and the piezoelectric element upon assembly, hence the increased reflection off the backing block and the eventual degradation in image quality. Furthermore, with an issue of poor surface integrity due to machining, it is difficult to increase alumina as scatterers more than a specific mass fraction ratio. In this study, we increased the portion of alumina within epoxy matrix by obtaining an enhanced surface integrity using a net shape fabrication method, and verified that this method could allow us to achieve higher ultrasonic attenuation. Backing blocks were net-shaped with various mass fractions of alumina to characterize the formability and the mechanical properties, including hardness, surface roughness and the internal micro-structure, which were compared with those of machined backing blocks. The ultrasonic attenuation property of the backing blocks was also measured.
AB - We report a method of fabricating backing blocks for ultrasonic imaging transducers, using alumina/epoxy composites. Backing blocks contain scatterers such as alumina particles interspersed in the epoxy matrix for the effective scattering and attenuation of ultrasound. Here, the surface integrity can be an issue, where the composite material may be damaged during machining because of differences in strength, hardness and brittleness of the hard alumina particles and the soft epoxy matrix. Poor surface integrity results in the formation of air cavities between the backing block and the piezoelectric element upon assembly, hence the increased reflection off the backing block and the eventual degradation in image quality. Furthermore, with an issue of poor surface integrity due to machining, it is difficult to increase alumina as scatterers more than a specific mass fraction ratio. In this study, we increased the portion of alumina within epoxy matrix by obtaining an enhanced surface integrity using a net shape fabrication method, and verified that this method could allow us to achieve higher ultrasonic attenuation. Backing blocks were net-shaped with various mass fractions of alumina to characterize the formability and the mechanical properties, including hardness, surface roughness and the internal micro-structure, which were compared with those of machined backing blocks. The ultrasonic attenuation property of the backing blocks was also measured.
KW - Alumina/epoxy composites
KW - Backing block
KW - Net shape fabrication
KW - Surface integrity
KW - Ultrasonic attenuation
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U2 - 10.1016/j.ultras.2015.10.027
DO - 10.1016/j.ultras.2015.10.027
M3 - Article
C2 - 26585217
AN - SCOPUS:84953397373
SN - 0041-624X
VL - 66
SP - 133
EP - 139
JO - Ultrasonics
JF - Ultrasonics
ER -