公开(公告)号：JP2001270714A

公开(公告)日：2001-10-02

申请号：JP2000086173

申请日：2000-03-27

Applicant: NAT INST FOR MATERIALS SCIENCE

Inventor： IKEGAMI TAKAYASU ,  RI TSUGUMITSU ,  MORI TOSHIYUKI ,  RI SHOKIN

IPC: C04B35/44 ,  C01F17/00

Abstract: PROBLEM TO BE SOLVED: To obtain an yttrium-aluminum-garnet(YAG) powder having a small primary particle diameter without aggregation. SOLUTION: An aqueous solution of basic salts of yttrium and aluminum is dropped into an aqueous solution of a basic salt containing carbonic acid at a concentration within the range of 0.1-2.5 mol/L and the pH is regulated to 7.4-9 under conditions in which sulfate ions are present to form a precipitate having a composition which is an amorphous phase according to X-rays and corresponds to a mixture of yttrium carbonate with dawsonite in 3:5 ratio of the yttrium carbonate to dawsonite. The resultant aqueous solution containing the formed precipitate is then filtered before crystalline yttrium carbonate is formed from the precipitate. Furthermore, the precipitate is then washed and calcined to provide the YAG powder.

公开(公告)号：JP2002154870A

公开(公告)日：2002-05-28

申请号：JP2000348042

申请日：2000-11-15

Applicant: NAT INST FOR MATERIALS SCIENCE

Inventor： IKEGAMI TAKAYASU ,  RI TSUGUMITSU ,  MORI TOSHIYUKI ,  RI SHOKIN

IPC: C04B35/443 ,  C01F7/16

Abstract: PROBLEM TO BE SOLVED: To provide a method for producing easily sinterable spinel powder. SOLUTION: An aqueous acidic salt solution containing magnesium ions and aluminum ions mixed in such a ratio as to obtain spinel is dropped into a basic aqueous solution adjusted to 35-80 deg.C again temperature and >=pH 10.5 and containing >=0.2 mol/l carbonate ions and ammonium ions to precipitate a precursor comprising a mixture of ammonium dawsonite hydrate and hydrotalcite, this precipitate is separated by filtration, washed and calcined at 900-1,400 deg.C to produce easily sinterable spinel powder. This spinel powder is compacted and sintered at 1,500-1,900 deg.C under

公开(公告)号：JP2001270775A

公开(公告)日：2001-10-02

申请号：JP2000086084

申请日：2000-03-27

Applicant: NAT INST FOR MATERIALS SCIENCE

Inventor： IKEGAMI TAKAYASU ,  RI TSUGUMITSU ,  MORI TOSHIYUKI ,  RI SHOKIN

IPC: C04B35/44 ,  C01F17/00 ,  H01S3/16

Abstract: PROBLEM TO BE SOLVED: To produce a yttrium-aluminum-garnet transparent sintered body that can be used as a laser host material, light-emitting tube for discharge lamps, an observation window, an element material for detector using fluorescence. SOLUTION: An acidic aqueous solution of yttrium and aluminum salts is dripped into a carbonate-including basic aqueous solution in the 0.1 m/l-2.5 m/l concentration range, then the pH is adjusted to 7.4-9 in the presence of sulfate ion to precipitate the composition that has an amorphous phase, when observed with X-rays, and has the composition corresponding to 3/5 ratio of yttrium carbonate to dawsonite. The precipitated mixture is filtered before crystalline yttrium carbonate is formed from the precipitated, the precipitate is washed and calcined to a YAG powder. Then, the YAG powder is formed and the formed product is fired. In a preferred embodiment, the filtered amorphous precipitate is calcined at 800-1,300 deg.C to form the YAG powder with primary particle sizes of 40-400 nm.