Patent EP0107919A1 successfully refreshed from Google Patents.
EP0107919A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Silicon nitride ceramic bodies
Assignee: British Ceramic Research Association Ltd
•
Filing: 1983-09-28
•
Granted: —
•
Expires: 2003-09-28
Abstract
Abstract A method of making a ceramic body by sintering a compact containing silicon nitride and one or more oxide sintering aids selected from the group comprising the oxides of magnesium, yttrium, chromium, molybdenum, iron, manganese, tungsten, cobalt, vanadium, uranium, nickel, titanium, hafnium, zirconium, niobium and tantalum.
Inventors
- 👤 John William care of The British Ceramic Cotton
- 👤 Robert care of The British Ceramic Swindells
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:43
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
47 words
A method of making a ceramic body characterised by sintering a compact containing silicon nitride and one or more oxide sintering aids selected from the group comprising the oxides of magnesium, yttrium, chromium, molybdenum, iron, manganese, tungsten, cobalt, vanadium, uranium, nickel, titanium, hafnium, zirconium, niobium and tantalum.
Claim 2
Independent Claim
47 words
A method of making a ceramic body characterised by sintering a compact containing silicon nitride and one or more oxide sintering aids selected from the group comprising the oxides of magnesium, yttrium, chromium, molybdenum, iron, manganese, tungsten, cobalt, vanadium, uranium, nickel, titanium, hafnium, zirconium, niobium and tantalum.
Claim 3
Dependent Claim
37 words
A method as claimed in claim 1, characterised in that the body is produced by forming a compact from a mixture of silicon nitride powder and one or more of said oxide sinteringaids and sintering the compact.
Claim 4
Dependent Claim
45 words
A method as claimed in claim 2, characterised in that the sintering aid or aids are present in an amount such that the total oxygen present in the sintered body, including any oxygen derived from impurities or contaminants, is in the range 3-7% by weight.
Claim 5
Dependent Claim
51 words
A method as claimed in claim 1, characterised in that the body is produced by forming a compact from a mixture of silicon and one or more of said sintering aids, heat treating the compact in a nitrogen containing atmosphere to produce a reaction-bonded silicon nitride composite and sintering the composite.
Claim 6
Dependent Claim
46 words
A method as claimed in claim 4, characterised in that the sintering aid or aids are present in an amount such that the total oxygen present in the silicon nitride composite, including any oxygen derived from impurities or contaminants, is in the range 3-7% by weight.
Claim 7
Dependent Claim
25 words
A method as claimed in claim 4 or 5, charecterised in that the heat treating is carried out at a temperature of 1200 - 1400°C.
Claim 8
Dependent Claim
24 words
A method as claimed in claim 4, 5 or 6, characterised in that the heat treating is carried out for 72 - 200 hours.
Claim 9
Independent Claim
26 words
A method as claimed in any preceding claim, characterised in that the total amount of sintering aid or aids is in the range 0.1-20% by weight.
Claim 10
Independent Claim
20 words
A method as claimed in any preceding claim characterised in that sintering is carried out in a substantially oxygen-free atmosphere.
Claim 11
Independent Claim
26 words
A method as claimed in any preceding claim characterised in that sintering is carried out in an atmosphere of 90% nitrogen and 10% hydrogen by weight.
Claim 12
Independent Claim
37 words
A method as claimed in any preceding claim characterised in that sintering is carried out in a powder bed composed of silicon nitride, boron nitride and magnesium oxide, after formation of the compact by pressing or shaping.
Claim 13
Independent Claim
24 words
A method as claimed in any preceding claim, characterised in that the sintering is carried out at a temperature of between 1200°C and 1800°C.
Claim 14
Independent Claim
23 words
A method as claimed in any preceding claim, characterised in that the sintering time is in the range twenty minutes to five hours.
References Cited (Backward Citations)
BE764545Q
Cited
US3950464A
Cited
GB2010913A
Cited
GB2010915A
Cited
US4332909A
Cited
EP0071997A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.