Method of producing a lithium phosphate sintered body and sputtering target

• US 20090045053A1
• Filed: 08/14/2008
• Published: 02/19/2009
• Est. Priority Date: 08/17/2007
• Status: Abandoned Application

• Current Assignee: Ulvac Incorporated
• Original Assignee: Ulvac Incorporated
• Inventors: Ito, Manabu, Nakajima, Hideaki, Kim, Poong, Mikashima, Takanori, Hidaka, Kouji, Hashiguchi, Shouichi, Oginosawa, Takatoshi
• Application Number:
  US12/228,588
• Publication Number:
  US 20090045053A1
• Time in Patent Office: Days
• US Class Current: 204/298.130
• CPC Class Codes: C04B 2235/3203 Lithium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/6581 Total pressure below 1 atmosphere, e.g. vacuum
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 35/447 based on phosphates , e.g. hydroxyapatite
• CPC Class Codes: C04B 35/62675 characterised by the treatment temperature
• CPC Class Codes: C04B 35/645 Pressure sintering
• CPC Class Codes: C04B 35/6455 Hot isostatic pressing
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

To attain a method of producing a lithium phosphate sintered body and a sputtering target capable of providing a high-density bulk body with no macro-size internal defect, the present invention provides a method of producing a lithium phosphate sintered body, including the steps of: calcining raw material powder of Li₃PO₄ at a temperature set to be 650° C. or more and less than 850° C.; pulverizing and sieving the calcined raw material powder; and sintering the sieved raw material powder to a predetermined shape. By setting a calcining temperature of the raw material powder to be 650° C. or more and less than 850° C., moisture absorbed into the raw material powder is effectively removed and generation of macro-size internal defects in the resultant bulk (sintered) body is suppressed. When the calcining temperature is less than 650° C., calcining processing is insufficient, so generation of macro-size internal defects cannot be suppressed effectively. Particularly for ease in pulverizing and sieving to obtain particle sizes of 400 μm or less, the calcining temperature is preferably set to be 650° C. or more and 750° C. or less.

Claims

1. A method of producing a lithium phosphate sintered body, comprising the steps of:

calcining raw material powder of Li₃PO₄ at a temperature set to be 650°

C. or more and less than 850°

C.;

pulverizing and sieving the calcined raw material powder; and

sintering the sieved raw material powder to a predetermined shape.

2. The method of producing a lithium phosphate sintered body according to claim 1, wherein in the step of calcining the raw material powder, the calcining temperature of the raw material powder is set to be 650°

C. or more and 750°

C. or less.

3. The method of producing a lithium phosphate sintered body according to claim 1, wherein the step of sintering the sieved raw material powder includes:

press-molding the raw material powder; and

heating the press-molded raw material powder.

4. The method of producing a lithium phosphate sintered body according to claim 3, wherein in the step of sintering the sieved raw material powder, the heating temperature of the raw material powder is set to be 900°

C. or more and 1000°

C. or less.

5. The method of producing a lithium phosphate sintered body according to claim 1, wherein the step of sintering the sieved raw material powder is a hot pressing step.

6. The method of producing a lithium phosphate sintered body according to claim 5, wherein in the step of sintering the sieved raw material powder, the heating temperature of the raw material powder is set to be 850°

C. or more and 1000°

C. or less.

7. The method of producing a lithium phosphate sintered body according to claim 1, wherein the raw material powder has a maximum particle size of 400 μ

m or less.

8. A sputtering target constituted of a lithium phosphate sintered body produced by the method of producing a lithium phosphate sintered body according to claim 1, wherein the sputtering target has a relative density of 95% or more.