Ngk Spark Plug Company, Limited

Kazuaki Kitamura

Kazushige Ohbayashi

Masato Yamazaki

Hideto Yamada

Takayuki Matsuoka

Toshiaki Kurahashi

Yasuyuki Okimura

Hisashi Kozuka

Takashi Kasashima

Katsuya Yamagiwa

Yoshiteru Honda

A lead-free piezoelectric ceramic composition including an alkali niobate/tantalate perovskite oxide main phase having piezoelectric properties and a different metal oxide. The mole ratio (Na/K) between Na (sodium) and K (potassium) in the main phase is 0.40&#x3c;(Na/K)&#x3c;3.0. The main phase has a crystal structure in which (i) first spots corresponding to a primitive lattice period and (ii) second spots corresponding to the lattice period two times the primitive lattice period and being weaker than the first spots appear in an electron beam diffraction image entering from the &#x3c;100&#x3e; direction with the main phase represented as a pseudo-cubic crystal system. Also, the area ratio of a crystal phase reflecting the second spots in the main phase is 33% or less, and the maximum grain size of crystals reflecting the second spots in the main phase is 25 nm or less.

Lead-free piezoelectric ceramic composition, piezoelectric element using the same, and method of manufacturing lead-free piezoelectric ceramic composition

A lead-free piezoelectric ceramic composition including an alkali niobate/tantalate perovskite oxide main phase having piezoelectric properties and a different metal oxide subphase. The mole ratio (Na/K) between Na (sodium) and K (potassium) in the main phase assumes a value in a range represented by 0.40&#x3c;(Na/K)&#x3c;3.0. The main phase has a crystal structure in which (i) first spots corresponding to a primitive lattice period and (ii) second spots corresponding to the lattice period two times the primitive lattice period and being weaker than the first spots appear in an electron beam diffraction image entering from the &#x3c;100&#x3e; direction with the main phase represented as a pseudo-cubic crystal system.

A lead-free piezoelectric ceramic composition includes a first crystal phase made of an alkali niobate/tantalate type perovskite oxide having piezoelectric properties, and a second crystal phase made of an M-Ti&#x2014;O spinel compound (where the element M is a monovalent to quadrivalent element).

Unleaded piezoelectric ceramic composition, piezoelectric element using same, device, and method for manufacturing unleaded piezoelectric ceramic composition

A lead-free piezo-electric porcelain composition which contains a main phase having voids and which is formed of a first crystal phase composed of an alkali niobate/tantalate-based perovskite oxide having piezo-electric characteristics; and a sub-phase containing a second crystal phase composed of an ABO-based compound (where the element A is a monovalent element and the element B is one or more divalent to hexavalent elements). The sub-phase fills voids present in the main phase.

Lead-free piezo-electric porcelain composition, piezo-electric element using the same, and method for producing lead-free piezo-electric porcelain composition

A lead-free piezoelectric ceramic composition mainly includes a first crystal phase (KNN phase) and a second crystal phase (NTK phase). In the first crystal phase (KNN phase), a plurality of crystal grains formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics is bound to each other in a deposited state. The second crystal phase (NTK phase) is formed of a compound containing titanium (Ti) and fills spaces between the crystal grains in the first crystal phase.

Lead-free piezoelectric ceramic composition, method for producing same, piezoelectric element using lead-free piezoelectric ceramic composition, ultrasonic processing machine, ultrasonic drive device, and sensing device

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Ise, Japan

Kazuaki Kitamura