Molded article based on PZT (Pb(Zr,Ti)0.sub.3, lead zirconate-lead titanate), method and intermediate product for its manufacture

• US 5,656,073 A
• Filed: 07/18/1996
• Issued: 08/12/1997
• Est. Priority Date: 09/27/1993
• Status: Expired due to Term

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Merklein, Stephan, Jahn, Rainer, Glaubitt, Walther
• Primary Examiner(s): BRUNSMAN, DAVID M
• Application Number:
  US08/683,825
• Time in Patent Office: 390 Days
• Field of Search: 106/287.19, 501/134, 501/136, 501/137
• US Class Current: 106/287.19
• CPC Class Codes: C04B 35/491 based on lead zirconates and lead titanates , e.g. PZT
• CPC Class Codes: C04B 35/62259 Fibres based on titanium oxide

Abstract

The intermediate product which is used in a method of making a molded arte, especially an endless PZT fiber, is itself made by a method including mixing an organic zirconium compound, Zr(OR¹)₄, and an organic titanium compound, Ti(OR²)₄, R¹ and R² being C₁ - to C₁₀ -alkyl groups, separately or together with 0 to 4 moles of at least one alcohol of the formula R³ --X--R⁴ --OH or R³ --CX--R⁴ --OH, X being O, S or an amine group and R³ and R⁴ being C₁ - to C₁₀ -alkyl groups, per mole of the zirconium and titanium compounds; reacting the zirconium and titanium compounds in the resulting mixture or mixtures with one to three moles of at least one C₂ - to C₁₀ -carboxylic acid per mole of the zirconium and titanium compounds to form at least one reaction mixture; mixing the at least one reaction mixture and reacting with 1 to 1.5 moles of one or more Pb(II)-carboxylates and/or Pb(IV)-carboxylates per mole of the zirconium and titanium compounds to form a combined mixture; subjecting this combined mixture to a hydrolytic condensation and then removing the volatile components from it to form a solid mass at ambient temperatures.

Claims

1. An intermediate product in a method of making a molded article, said intermediate product being made by a method comprising the steps of:

a) providing at least one organic zirconium compound of formula I,

space="preserve" listing-type="equation">Zr(OR.sup.1).sub.4, (I)

and at least one organic titanium compound of the formula II,

space="preserve" listing-type="equation">Ti(OR.sup.2).sub.4, (II)

wherein R¹ and R² are each independently selected from the group consisting of straight, branched and cyclic alkyl groups having 1 to 10 carbon atoms;

b) reacting from 1 to 3 moles of at least one carboxylic acid having 2 to 10 carbon atoms per mole of the at least one organic titanium plus the at least one organic titanium compound of formulas I and II present with the at least one organic titanium and the at least one organic zirconium compound to form at least one reaction mixture;

c) reacting said at least one reaction mixture formed in step b) with 1 to 1.5 moles of at least one Pb-containing carboxylate per mole of the at least one organic titanium compound plus the at least one organic zirconium compound to form a combined mixture, the at least one Pb-containing carboxylate being selected from the group consisting of Pb(II)-carboxylates and Pb(IV)-carboxylates, wherein each of said Pb(II)-carboxylates and Pb(IV)-carboxylates is made from an acid member selected from the group consisting of substituted and unsubstituted, monofunctional and polyfunctional, saturated and unsaturated, straight chain and branched chain, cyclic and aromatic carboxylic acids having 1 to 18 carbon atoms and substituted and unsubstituted, monofunctional and polyfunctional, saturated and unsaturated, straight chain and branched chain, cyclic and aromatic hydroxycarboxylic acids having 2 to 18 carbon atoms; and

d) subjecting the combined mixture formed in step c) to a hydrolytic condensation and removing volatile components from the combined mixture until a solid mass is formed at ambient temperatures.

2. The intermediate product as defined in claim 1, wherein a molar ratio of titanium to zirconium therein is 47:

53.

3. The intermediate product as defined in claim 2, wherein said method further comprises the step of forming said Pb(II) carboxylate at least partially in situ from Pb(II) oxide and at least one other carboxylic acid.

4. The intermediate product as defined in claim 3, wherein said method further comprising the step of forming said carboxylic acids at least partially in situ from at least one carboxylic acid anhydride.

5. The intermediate product as defined in claim 1, wherein the Pb-containing carboxylate includes a lead acetate compound of the formula V

6. The intermediate product as defined in claim 1, wherein said method includes the step of doping the at least one reaction mixture with a foreign metal, said foreign metal not including zirconium, titanium or lead.

7. The intermediate product as defined in claim 1, further comprising at least one metal cation member selected from the group consisting of Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺, said at least one metal cation member partially replacing said Pb(II).

8. The intermediate product as defined in claim 1, further comprising at least one metal cation member selected from the group consisting of Sn⁴⁺ and Hf⁴⁺, said at least one metal cation member partially replacing at least one member selected from the group consisting of Ti⁴⁺ and Z⁴⁺.