Ultrasound transducer alignment materials

Ultrasound transducers use materials with a variety of acoustic impedances.
Using materials with different acoustic impedances requires use of alignment materials.
Krosaki Harima provides a wide assortment of ceramic materials that can be used as alignment materials for ultrasound transducers.
Our lineup covers a broad range of acoustic impedances.
We also provide high-accuracy machining services.
Major applications of ultrasound transducers: ultrasound diagnosis devices, fish finders

Macerite HSP
Mica based glass ceramics
Acoustic impedance
14.5×106 kg/m2s
Macerite CE
Composite materials of ceramics and resin
Acoustic impedance
11.5×106 kg/m2s
NEXCERA™ N113B
Cordierite based ceramics
Acoustic impedance
21.0×106 kg/m2s

Material characteristics

Name Macerite HSP Macerite CE NEXCERA™
N113B
General Properties Bulk Density g/cm3 2.67 2.3 2.5
Water Adsorption Raito % 0 0.3 or less 0
Porosity % 0 - -
Acoustic Properties Longitudinal Wave Speed m/s 5410 4825 8400
Transverse Wave Speed m/s 3120 2935 4490
Acoustic Impedance(ρc) kg/m2s 14.5×106 11.5×106 21.0×106
Mechanical Properties Flexural Strength MPa 160 120 210
Compressive Strength MPa 440 390 -
Young's Modulus GPa 65 49 130
Poisson's Ratio 0.25 0.23 0.30
Hardness GPa 2.2 - 8
Electrical Properties Electrical Resistivity [RT] Ωcm 4.8×1015 1.6×1013 1×1013
Dielectric Constant [1MHz] 6.5 5.8 4.7
Dielectric Loss (tanδ) [1MHz] 0.003 0.007 0.006
Dielectric Strength kV/mm 10 - -
Thermal Properties Themal Expansion[RT] /℃ 9.8×10-6 7.6×10-6 0.05×10-6
Themal Conductivity [RT] W/m・K 1.6 1.6 3.7
Specific Heat [RT] J/g・K 0.8 - 0.83
Crystal Phase Fluorphlogopite
/ Glass phase		 Wollastonite
/ Resin		 Cordierite base

【Reference data】Acoustic impedances for main materials (Longitudinal Wave)

Materials Bulk density Sonic speed Acoustic impedance Remarks
(g/cm3) (m/s) (kg/m2s)
Air 0.00129 331 428 1℃, 1 atmospheric pressure
Water 1 1452 1.5×106 25℃
Natural rubber 0.97 1500 1.5×106 1MHz
Polyethylene 0.9 1950 1.8×106
Ice 0.917 3980 3.7×106
Macerite CE 2.3 4825 11.5×106
Glass 2.42 5440 13.2×106
Macerite HSP 2.67 5410 14.5×106
Aluminum 2.69 6420 17.3×106
NEXCERA™ N113B 2.5 8400 21.0×106
Lead 11.3 1960 22.4×106
Copper 8.96 5010 44.6×106
Steel 7.86 5950 46.4×106

* The data indicated herein is representative values and not guaranteed values.

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