公开(公告)号：JPH0448704A

公开(公告)日：1992-02-18

申请号：JP15524190

申请日：1990-06-15

Applicant: TOSOH CORP

Inventor： MATSUI KOJI ,  UEMA TSUTOMU ,  MITSUI HIDEO ,  MURAKAMI TSUGIO

IPC: C01G49/00 ,  H01F1/11

Abstract: PURPOSE:To simply manufacture barium ferrite magnetic powder being symmetricalfine grains, having high dispersibility and a plate shape, moreover a big magnetization value by spraying slurry mainly containing a barium hydroxide water solution and iron oxide and/or hydrated iron oxide in a gas atmosphere at not less than 700 deg.C to be subjected to thermal decomposition. CONSTITUTION:Slurry mainly containing a barium hydroxide water solution and iron oxide and/or iron hydroxide is used as a raw material. Primary iron oxide or the like is mentioned as iron oxide and primary iron or the like is mentioned as hydrated iron oxide. On the other hand, as to barium hydroxide to be contained a raw material slurry, concentration of a water solution is desirably to be set within a range of a solution degree of barium hydroxide. Further, as a preparation method of the raw material slurry, a dispersion mixing type stirrer is used. Next, this raw material slurry is sprayed in a gas atmosphere of steam or the like above 700 deg.C to be subjected to thermal decomposition. By this method, barium ferrite magnetic powder having a grain diameter of 0.01 to 0.3mum having high dispersibility, a plate shape and a high magnetization value can be obtained economically and with good efficiency.

公开(公告)号：JPH04202016A

公开(公告)日：1992-07-22

申请号：JP32994590

申请日：1990-11-30

Applicant: TOSOH CORP

Inventor： UEMA TSUTOMU ,  MITSUI HIDEO ,  OKAI MICHIJI

IPC: C01G25/02

Abstract: PURPOSE:To uniformly control compsn. and particle diameter and to improve dispersibility by maintaining a constant concn. of a precipitate and a constant pH when a mixed aq. soln. contg. salts of Zr, Y, Ca, etc., is allowed to react with an alkali soln. and Zr oxide-based fine powder is produced from the resulting precipitate. CONSTITUTION:A mixed aq. soln. contg. water-soluble salts of Zr and one or more among Y, Ca, Mg and Ce is prepd. and allowed to react with an alkali soln. to form a precipitate. At this time, a constant pH is maintained in the reaction system and the constant concn. of the precipitate in the system is maintained from the beginning of the reaction to the end. The resulting precipitate is separated, dried and fired.

公开(公告)号：JPH05147944A

公开(公告)日：1993-06-15

申请号：JP34168691

申请日：1991-12-02

Applicant: TOSOH CORP

Inventor： UEMA TSUTOMU ,  DOI MASAHARU ,  OKAI MICHIJI

IPC: C01G25/02

Abstract: PURPOSE:To obtain high purity zirconium oxide powder having uniformly controlled particle diameter and excellent dispersibility of particles. CONSTITUTION:An aq. soln. of zirconium salts including zirconium oxide hydrate and an alkali soln. are fed into a reactional system and brought into contact with each other while maintaining a constant pH in the reactional system. The resulting precipitate is separated, dried and fired to produce zirconium oxide powder.

公开(公告)号：JPH01317167A

公开(公告)日：1989-12-21

申请号：JP3507889

申请日：1989-02-16

Applicant: TOSOH CORP

Inventor： OIZUMI FUKUO ,  KAMIMURA KINICHIRO ,  MINOYA KATSUO ,  KATO AKIYOSHI ,  UEMA TSUTOMU

IPC: C04B35/48 ,  C04B35/486 ,  C23C14/08 ,  C23C14/24 ,  C23C14/34

Abstract: PURPOSE:To readily produce a calcined compact of ZrO2 optimally used for forming thin ZrO2 films according to a vacuum deposition or sputtering method, etc., by forming ZrO2 powder having a specific particle diameter and specified purity at ambient temperature and calcining the resultant compact. CONSTITUTION:ZrO2 powder containing >=30wt.% particles having >=10 to =2wt.% particles having =99.0wt.% purity including unavoidably contained HfO2 is formed at ambient temperature and then calcined. Thereby, the objective calcined compact having >4.9g/cm density and the afore-mentioned purity is obtained. This calcined compact is optimally used for forming thin films according to a vacuum deposition or sputtering method, etc., and homogeneous thin ZrO2 films excellent in characteristics as optical films can be obtained with excellent productivity.

公开(公告)号：JPH06191846A

公开(公告)日：1994-07-12

申请号：JP34587692

申请日：1992-12-25

Applicant: TOSOH CORP

Inventor： KUMA KIMITAKA ,  UEMA TSUTOMU ,  OGAWA NOBUHIRO ,  MORI TAKASHI

IPC: C01G15/00 ,  C04B35/00 ,  C04B35/457 ,  C04B35/495 ,  C23C14/34

Abstract: PURPOSE:To obtain In2O3 powder capable of producing a high density ITO sintered compact by calcining III(OH)2 obtained by prescribing the mixing speed of an In salt aq. solution with an alkali aq. solution. CONSTITUTION:When the In salt aq. solution of 60-100 deg.C is mixed with the alkali aq. solution so as to be 3-5 OH/In ratio, In2O3 powder is obtained (A) by mixing at the rate of >=0.15 OH/In per minute at the time of supplying the alkali aq. solution to the In salt aq. solution, (B) by mixing at the rate of >=0.01 In/OH per minute at the time of supplying the In salt aq. solution to the alkali aq. solution and (C) by mixing by continuously supplying the In salt aq. solution and the alkali aq. solution and next, cleaning, filtering, drying and calcining the obtained In(OH)2. The In2O3 powder has 15-30m /g BET specific surface area, the ratio of BET diameter to crystallite diameter of

公开(公告)号：JPH0632615A

公开(公告)日：1994-02-08

申请号：JP21228292

申请日：1992-07-17

Applicant: TOSOH CORP

Inventor： MATSUI KOJI ,  UEMA TSUTOMU ,  DOI MASAHARU ,  MORI TAKASHI

IPC: C01G25/02 ,  C04B35/48

Abstract: PURPOSE:To obtain the subject zirconia having improved formability and sintering property by drying a hydrated zirconia gel containing a prescribed amount of an alkali metal based on ZrO2 and calcining the dried product at a specific temperature. CONSTITUTION:A hydrated zirconia sol is produced by adding a proper amount of a stabilizing agent such as Y2O3 to an aqueous solution of a zirconium salt such as zirconium oxychloride and hydrolyzing at the boiling temperature. The sol is incorporated with an aqueous solution of an alkali metal compound such as NaOH and the obtained suspension having pH of >=8 is filtered and washed with water until the pH of the filtrate reaches /g and high dispersibility.

公开(公告)号：JPH04130018A

公开(公告)日：1992-05-01

申请号：JP30390190

申请日：1990-11-13

Applicant: TOSOH CORP

Inventor： YAMAMOTO KAZUAKI ,  UEMA TSUTOMU ,  MORI TAKASHI

IPC: C04B35/48 ,  C01G25/02

Abstract: PURPOSE:To obtain the zirconia powder yielding the secure sintered body which does not generate the crack occurring in the volumetric expansion and shrinkage arising from a phase transition by specifying the specific surface area and particle size of the zirconia powder. CONSTITUTION:This zirconia powder has 5 to 30m /g specific surface area and 45 to 75wt.% ratio of 1.3 to 3.0mu, 1 to 20mu in average of the particle diameters measured by a centrifugal settling method. The secure zirconia sintered body which is free from cracks and in which >=20% of the voids are intraparticle voids is obtd. by sintering the above-mentioned zirconia powder. The crack of the sintered body is hardly suppressed if the average particle diameter of the particle of the above-mentioned zirconia powder is

公开(公告)号：JPH0489319A

公开(公告)日：1992-03-23

申请号：JP20247390

申请日：1990-08-01

Applicant: TOSOH CORP

Inventor： UEMA TSUTOMU ,  MITSUI HIDEO ,  OKAI MICHIJI

IPC: C01G25/02

Abstract: PURPOSE:To uniformly control the particle size and to improve dispersibility and purity by effecting the reaction of a Zr salt soln. and an alkali soln. while maintaining the pH and precipitation concn. constant in the reaction system, and then drying and firing the obtd. precipitate. CONSTITUTION:A reaction tank is charged with a suspension comprising precipitate (e.g. Zr(OH)4) and pure water, having pH 2.0-13.0 and 10-300g/l concn. in terms of ZrO2. To this suspension, a Zr salt soln. and an alkali soln. are separately introduced at one time by a specific ratio of flow rates to produce precipitate in a manner that the pH and precipitation concn. above described are maintained. Then this precipitate is separated, washed with water, dried and fired at 600-1100 deg.C.

公开(公告)号：JPH02163908A

公开(公告)日：1990-06-25

申请号：JP31761388

申请日：1988-12-17

Applicant: TOSOH CORP

Inventor： MATSUI KOJI ,  UEMA TSUTOMU ,  MURAKAMI TSUGIO

IPC: C01G49/00 ,  H01F1/11

Abstract: PURPOSE:To enable the title sheet type magnetic material in even fine grain size and high dispersion properties as well as high magnetizing value to be easily manufactured by a method wherein a water solution mainly containing a compound exceeding one kind out of Ba, Sr and Pb as well as Fe compound is sprayed in oxygen or gaseous atmosphere containing oxygen at specified temperature to be thermally decomposed. CONSTITUTION:A water solution mainly containing almost exceeding one kind of compound selected from Ba, Sr and Pb as well as Fe compound is sprayed in oxygen or gaseous atmosphere containing oxygen at the temperature exceeding 1000 deg.C to be thermally decomposed. For example, 1l of the water solution containing 0.0714mol of barrier chloride, 0.364mol of ferrous chloride (III), 0.0321mol of cobalt chloride (II), 0.0321mol of titanium chloride (IV) is prepared and then sprayed in a reactor containing atmospheric air. At this time, the spraying process is executed in such a way that the gas flow rate of propane- oxygen flame may be controlled to raise the temperature inside the reactor to 1100 deg.C as well as the water solution may be sprayed at the spray rate of 1l/Hr from two liquid nozzles in the spray drip of around 10mum so as to satisfactorily pass through the flame zone.