Powder metallurgy processes – Powder metallurgy processes with heating or sintering – Powder shape or size characteristics
Patent
1984-08-06
1986-04-15
Lieberman, Allan M.
Powder metallurgy processes
Powder metallurgy processes with heating or sintering
Powder shape or size characteristics
29 2535, 419 5, 419 8, 419 31, 419 32, 419 48, 419 60, B22F 300, B22F 312, B22F 324
Patent
active
045826803
ABSTRACT:
An acoustical transducer is provided with an acoustically absorbant backing material having an acoustical impedance precisely matching the impedance of the piezoelectric element in the transducer. The backing material is a multiphase mixture of selected materials, such as a low melting point alloy (InPb) and one or more powders having high impedance characteristics (tungsten and copper). The slope of the curve impedance versus volume fraction of the backing components is low, thus allowing the impedance of the material to be precisely controlled. The backing material is preferably electrically conductive and is fuzed to one surface of the piezoelectric element to further improve the output characteristics of the transducer.
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patent: 3663842 (1972-05-01), Miller
Sayers et al., "Ultrasonic Properties of Transducer Backings", Ultrasonics, Mar. 1984, pp. 57-60.
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Bar-Cohen Yoseph
Hoppe Wally C.
Stubbs David A.
Lieberman Allan M.
Systems Research Laboratories Inc.
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