← Back to Patent Explorer
US5254510A Expired / Lapsed US ⏱️ 0.0 years remaining

Heat resistive phosphate sintered bodies and a process for producing the same

Assignee: NGK Insulators Ltd
•
Filing: 1990-08-28
•
Granted: 1993-10-19
•
Expires: 2010-08-28
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A heat resistive phosphate sintered body including a solid solution of R y Zr 4 Si x P 6-x O 24 in which O≦x≦2, 2/3≦y≦2, R is a combination of one or more of cations having 2-3 valences, and x and y meet an electrically neutral condition, wherein a thermal expansion hysteresis loss is not more than 0.3%, and a dimensional change after a heat cycling in which heating and cooling are repeated between 100° C. and 1,200° C. at 100 times is not more than 1%. A process for producing such a heat resistive phosphate is also disclosed. The process includes the steps of preparing a batch mixture, as a starting material, of (ZrO) 2 P 2 O 7 , ZrP 2 O 7 , RO and/or a phosphate of R in which R is a combination of one or more of cations having two or three valences, and if necessary further SiO 2 , calcining, milling and shaping the thus prepared mixture, and firing the thus shaped body, wherein a calcining temperature is not less than 1,400° C. and equal to or higher than a firing temperature, the starting material is a powder milled to an average particle diameter of not more than 7 μm, and the firing temperature is not less than 1,300° C.

Inventors

  • 👤 Keiji Matsuhiro
  • 👤 Tsuneaki Ohashi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 14:55
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/447

Claims Analysis

Total Claims: 21
Claim 1
Independent Claim 121 words
A heat resistive phosphate sintered body consisting essentially of a solid solution of R y Zr 4 Si x P 6-x O 24 , wherein x is greater than zero and less than or equal to two, 2/3≦y≦2, R is a combination of one or more cations having a charge of +2 or +3, and x and y satisfy an electrically neutral condition, said heat resistive phosphate sintered body having a thermal expansion hysteresis not more than 0.3%, a dimensional change after a heat cycling not more than 1%, and a four point flexural strength not less than 100 kg/cm 2 after the heat cycling, wherein the heat cycling comprises 100 heating and cooling cycles between 100° C. and 1,200° C.
Claim 2
Dependent Claim 121 words
A heat resistive phosphate sintered body consisting essentially of a solid solution of R y Zr 4 Si x P 6-x O 24 , wherein x is greater than zero and less than or equal to two, 2/3≦y≦2, R is a combination of one or more cations having a charge of +2 or +3, and x and y satisfy an electrically neutral condition, said heat resistive phosphate sintered body having a thermal expansion hysteresis not more than 0.3%, a dimensional change after a heat cycling not more than 1%, and a four point flexural strength not less than 100 kg/cm 2 after the heat cycling, wherein the heat cycling comprises 100 heating and cooling cycles between 100° C. and 1,200° C.
Claim 3
Dependent Claim 26 words
The heat resistive phosphate sintered body of claim 1, wherein the sintered body has microcracks and the thermal expansion hysteresis of the sintered body is 0.03-0.25%.
Claim 4
Dependent Claim 26 words
The heat resistive phosphate sintered body of claim 1, wherein the coefficient of thermal expansion of the sintered body is not more than 25×10 -7 /°C.
Claim 5
Dependent Claim 30 words
The heat resistive phosphate sintered body of claim 1, wherein a weight-reduction rate of the sintered body after the heat treatment of 1,400° C.×100 hours is not more than 5%.
Claim 6
Dependent Claim 31 words
The heat resistive phosphate sintered body of claim 1, wherein a self-weight softening percentage of the sintered body after the heat treatment of 1,400° C.×5 hours is not more than 1%.
Claim 7
Dependent Claim 33 words
The heat resistive phosphate sintered body of claim 1, wherein a dimensional change rate of the sintered body after the heat treatment at 1,400° C. for 100 hours is not more than 3.5%.
Claim 8
Dependent Claim 23 words
The heat resistive phosphate sintered body of claim 6, wherein the four point flexural strength is not less than 200 kg/cm 2 .
Claim 9
Dependent Claim 26 words
The heat resistive phosphate sintered body of claim 1, wherein a coefficient of thermal expansion of the sintered body is not more than 10×10 -7 /°C.
Claim 10
Dependent Claim 14 words
The heat resistive phosphate sintered body of claim 1, which has a honeycomb structure.
Claim 11
Dependent Claim 26 words
The heat resistive phosphate sintered body of claim 1, which comprises a combination of one or more of elements of Group IIa in the Periodic Table.
Claim 12
Dependent Claim 21 words
The heat resistive phosphate sintered body of claim 1, wherein R consists of at least one of Ca, Sr and Ba,
Claim 13
Dependent Claim 136 words
A process of producing a heat resistive phosphate sintered body having a composition of R y Zr 4 Si x P 6-x O 24 , R being one or more cations having a charge of +2 or +3, comprising the steps of: preparing a batch mixture of (ZrO) 2 P 2 O 7 , ZrP 2 O 7 , RO and/or a phosphate of R, and SiO 2 ; calcining said bach mixture into a calcined powder at a calcining temperature not less than 1,400° C.; milling said calcined powder to an average particle diameter not more than 7 microns; shaping the calcined powder into a shaped body after milling; firing the shaped body at a firing temperature not less than 1,300° C., wherein said calcining temperature is equal to or higher than the firing temperature.
Claim 14
Dependent Claim 136 words
A process of producing a heat resistive phosphate sintered body having a composition of R y Zr 4 Si x P 6-x O 24 , R being one or more cations having a charge of +2 or +3, comprising the steps of: preparing a batch mixture of (ZrO) 2 P 2 O 7 , ZrP 2 O 7 , RO and/or a phosphate of R, and SiO 2 ; calcining said bach mixture into a calcined powder at a calcining temperature not less than 1,400° C.; milling said calcined powder to an average particle diameter not more than 7 microns; shaping the calcined powder into a shaped body after milling; firing the shaped body at a firing temperature not less than 1,300° C., wherein said calcining temperature is equal to or higher than the firing temperature.
Claim 15
Dependent Claim 30 words
The process for producing the heat resistive phosphate sintered body of claim 12, wherein the calcined powder is milled to the average particle diameter of not more than 2.5 μm.
Claim 16
Dependent Claim 25 words
The process for producing the heat resistive phosphate sintered body of claim 12, comprising the step of plasticizing the batch mixture before the shaping step.
Claim 17
Dependent Claim 25 words
The process for producing the heat resistive phosphate sintered body of claim 12, wherein said calcining and said firing temperature are held for 1-24 hours.
Claim 18
Dependent Claim 20 words
The process for producing the heat resistive phosphate sintered body of claim 12, wherein the calcining temperature is 1,500°-1,600° C.
Claim 19
Dependent Claim 22 words
The process for producing the heat resistive phosphate sintered body of claim 12, wherein the firing temperature is b 1,400° C.-1,600° C.
Claim 20
Dependent Claim 21 words
The process for producing the heat resistive phosphate sintered body of claim 12, wherein the shaping step is effective by extrusion.
Claim 21
Dependent Claim 19 words
The heat resistive phosphate sintered body of claim 1, wherein the grain size is not more than 10 microns.

References Cited (Backward Citations)

DE3609730A1 Cited
EP0260893A2 Cited
EP0306242A2 Cited
US4925816A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-10-18 1997-04-19 1997-10-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-10-18 2001-04-19 2001-10-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-10-18 2005-04-19 2005-10-19 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag