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WO1999020579A1 - SINTERADDITIVE UND SiO2-ENTHALTENDE SILICIUMNITRIDWERKSTOFFE, EIN VERFAHREN ZU DEREN HERSTELLUNG UND DEREN VERWENDUNG - Google Patents

SINTERADDITIVE UND SiO2-ENTHALTENDE SILICIUMNITRIDWERKSTOFFE, EIN VERFAHREN ZU DEREN HERSTELLUNG UND DEREN VERWENDUNG Download PDF

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Publication number
WO1999020579A1
WO1999020579A1 PCT/EP1998/006375 EP9806375W WO9920579A1 WO 1999020579 A1 WO1999020579 A1 WO 1999020579A1 EP 9806375 W EP9806375 W EP 9806375W WO 9920579 A1 WO9920579 A1 WO 9920579A1
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WO
WIPO (PCT)
Prior art keywords
sio
silicon nitride
additives
sintering additives
sintering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1998/006375
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English (en)
French (fr)
Inventor
Gerhard WÖTTING
Mathias Herrmann
Grit Michael
Stefan Siegel
Lutz Frassek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayer AG filed Critical Bayer AG
Priority to AU97491/98A priority Critical patent/AU9749198A/en
Priority to EP98951501A priority patent/EP1025062A1/de
Publication of WO1999020579A1 publication Critical patent/WO1999020579A1/de
Anticipated expiration legal-status Critical
Priority to US11/583,560 priority patent/US7244686B2/en
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/043—Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC]
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Definitions

  • the present invention relates to sintering additives and SiO 2 -containing silicon nitride materials, a process for their production and their use.
  • Ceramic materials are used more and more in device and apparatus construction - especially in bearings (Ceramic Airframe Bearings: Lubrications Engeneering, 31 (1975), 558-564). All-ceramic bearings have proven themselves particularly in the area of insufficient lubrication and in corrosive media. In the most diverse areas of application for components made of high-performance ceramics, however, it has been shown that they degrade and a reliable service life forecast is not possible. The corrosion resistance depends to a large extent on the type of the attacking medium, the material composition and the superimposed mechanical stress. The reason for this lies in the different reaction behavior of the individual structural components of the ceramics (matrix grains, grain boundary phases, impurities) against acids, bases or under hydrothermal conditions.
  • Liquid-phase sintered materials such as silicon nitride or silicon carbide (LPSSIC), which contain 5 to 20 vol.% Grain boundary phase, show an attack along the grain boundary phase in acids and bases.
  • LPSSIC silicon nitride or silicon carbide
  • the main point of attack for acid and alkali corrosion in the temperature range ⁇ 180 ° C is the grain boundary phase.
  • this is not completely removed, which is clear from the fact that even materials that are corroded right through to the center still have strengths of 300 to 400 MPa.
  • Acid resistance of silicon nitride materials with rare earth oxides, Y2O3 and optionally Al 2 O 3 as sintering additives is the reduction in the amount of these sintering additives.
  • the improved corrosion resistance has to be bought through higher production costs, since HIP technology is used for compression (EP-A 414 383). From mater. Res. Soc. Symp. Proc. 287 (1993) and Key Engineering Materials 113 (1996), pp. 227-237 it is also known that there is a reduction in corrosion at very high concentrations of acids, which in the case of phosphoric acid could be explained by the formation of a passivation layer , see Corrosion of High Performance Ceramics; Springer Verlag, Berlin, 1992; Pp. 76 to 78.
  • the object of the invention was therefore to provide ceramic materials based on Si 3 N 4 which have high corrosion resistance, ie for example a small change in mass and low strength losses after acid treatment.
  • a silicon nitride material regardless of the way in which it is produced, has a high corrosion resistance to acids if the highest possible SiO 2 content is achieved and the formation of silicon oxide nitride is avoided, ie if the molar ratio of silicon dioxide in the Grain boundary phase to the sintering additives including SiO 2 in the grain boundary phase> 60% and the oxide nitride content (Si 2 N O content) ⁇ 1%.
  • the invention therefore relates to sintering additives and silicon nitride materials containing SiO 2 , the molar ratio of the silicon dioxide in the grain boundary phase to the sintering additives including SiO in the grain boundary phase> 60%, preferably> 65%, and the oxide nitride content (SiO 2 N 2 O) ⁇ 1 % is.
  • Sintering additives are understood to be the added substances which form the liquid phase during sintering and remain in the grain boundary phase.
  • the grain boundary phase in silicon nitride materials is formed by solidification of the liquid phase that is present during sintering. It contains the sintering additives, silicon dioxide and partially dissolved silicon nitride. Depending on the conditions of the thermal treatment (cooling rate, etc.), it is amorphous or partially crystalline. As a rule, it wets the silicon nitride particles and forms a three-dimensional one
  • Sintering additives of the grain boundary phase in the sense of the invention are preferably Y 2 O 3 , Sc O 3 , rare earth oxides, alkaline earth oxides and Al 2 O 3 .
  • the amount of sintering additives + SiO added is preferably selected so that the proportion of grain boundary phase in the sintered material is ⁇ 20% by volume, particularly preferably 0.1-17% by volume, very particularly preferably 3 to 15% by volume.
  • the silicon nitride materials have further
  • Such additives are, for example, reactive additives, ie those which react with Si 3 N and form SiO 2 , such as TiO 2 , WO 3 and / or MoO 3 .
  • TiO 2 reacts to form TiN
  • WO 3 and MoO 3 form silicides with simultaneous oxidation of Si 3 N
  • additives which are retained as dispersion phases such as SiC, TiN, MoSi 2 , TiCN and / or HfO 2, or else additives which form mixed crystals, such as A1N, with the Si 3 N 4 .
  • the additives which react with Si 3 N 4 and form SiO are preferably present in an amount of 0 to 10 mol%, preferably ⁇ 5 mol%, based on Si 3 N 4 .
  • the additives obtained as the dispersion phase are preferably in one
  • Mixed crystal-forming additives are preferably present in amounts of 0 to 50 mol%, preferably ⁇ 15 mol%, based on Si 3 N 4 .
  • the porosity of the material is ⁇ 2%.
  • the invention also relates to a method for producing the material according to the invention, according to which either alone or in combination
  • the Si 3 N 4 powder used is thermally oxidized alone or together with the sintering additives and optionally other additives, or
  • the Si 3 N 4 powder is tribooxidized alone or together with the sintering additives and, if appropriate, further additives, or
  • Any commercially available Si 3 N 4 powder can be used for the processes according to a), b) and c).
  • the thermal oxidation a) takes place in an oxidizing atmosphere, preferably in air, O 2 and / or water vapor at temperatures from 300 to 1400 ° C.
  • a grinding step can also be connected upstream or downstream.
  • Tribooxidation b) during grinding is carried out by intensive grinding of the Si 3 N powder dry or in a liquid, such as H 2 O, an organic
  • Solvents such as acetone, hexane or alcohol.
  • the grinding is preferably carried out in ball mills until the ground Si 3 N 4 has an average particle size (d 50 value), preferably measured using the Master Sizer S ⁇ 2.5 ⁇ m, preferably ⁇ 1 ⁇ m, and this is the has the required molar ratio of SiO 2 to sintering additives.
  • variant c) can be used as SiO 2 -forming component siloxanes, silanes, silicone resins (see Material Science and Technology Vol. 178, Processing of Ceramics, VCH, Weinheim, (1996) Part II, 4-47, DE-A 43 18 974, EP-A 0 412 428, and the reactive additives described, such as TiO 2 , WO 3 and MoO 3 , are used.
  • the amount of SiO 2 -forming components depends on the desired SiO content of the sintered molding.
  • the sintered material is preferably produced from the powder mixtures obtained according to variants a), b) and / or c) in accordance with the generally customary ceramic technology.
  • the ratio of SiO 2 to the sintering additives can also be influenced by incorporating the sintering additives or the mixed crystal-forming additives and / or SiO 2 in the silicon nitride crystal lattice.
  • the SiO 2 / sinter additive ratio when determining the SiO 2 / sinter additive ratio, the a proportion of the original sinter additives or SiO 2 is used in order to reduce the a proportion built into the crystal lattice. This is particularly important for the ⁇ '- and ⁇ '-SiAlONs, for example according to the following
  • the invention also relates to the use of the materials according to the invention in equipment and apparatus construction, in particular in bearings.
  • Si 3 N 4 powder (Baysinid®, available from Bayer AG) Y 2 O 3 (grade fine, available from HC Starck) and Al 2 O 3 powder (AKP-50®, available from Sumitomo ) and TiO 2 (P25, available from Degussa) are mixed in accordance with the composition given in Table 1, homogenized in an agitator ball mill for 3 hours in aqueous suspension, spray-dried and pressed into bodies of 50 ⁇ 60 ⁇ 8 mm.
  • the particle size (d 50 value) of the offset after the homogenization was 0.5 ⁇ m, measured with the Master Sizer S at pH 11.0.
  • the bodies are heated in air at 600 ° C for 1 h. They are gas pressure sintered at 1830 ° C for 1.5 h at 50 bar N 2 .
  • the weight loss of the samples was ⁇ 0.3 to 1.8%, depending on the TiO 2 content of the batch.
  • the sintered samples are cut into test bars and ground.
  • the batch 1 b was milled at a higher speed for 6 h in order to increase the oxygen content.
  • Example 2a was sintered in a BN-coated graphite crucible in a BN powder bed. The weight loss was 1.8%.
  • Example 2b the sample was sintered in an RBSN crucible. The weight loss was 0.2%.
  • Example 2c an additional 1.5% silicone resin was used as the binder.
  • Examples 2e and 2f were produced from plasma-chemically produced silicon nitride powder with a surface area of 60 m 2 / g and an SiO 2 content of 8%. The samples were hot pressed at 1800 ° C.
  • test specimens were produced as in Example 1.
  • the compaction was carried out by a sintering HIP process, the weight loss being reduced to ⁇ 1.5% by the RBSN crucible and a high sample volume / volume ratio.
  • test specimens were produced as in Example 2.
  • test specimens were produced analogously to Example 1, the sintering was carried out at 1800 ° C.
  • Bending fracture bars 3 x 4 x 50 mm were cut out of the sintered bodies and used to determine the mechanical properties and the corrosion behavior. The strength was determined using the 4 point method (support distance 20/40 mm).
  • the corrosion behavior was determined in thermostatted glass containers with 1 N acid.
  • the acid / solid ratio was> 200 ml / 10 g samples.
  • the acid was changed every 100 h.
  • the loss of mass of the samples was determined by periodic weighing after defined periods of time (see ⁇ m in Tab. 1).
  • the samples were distilled with H 2 O-dist. rinsed and dried.
  • the content of oxide nitride was determined on the samples by means of XRD measurements.
  • CuK ⁇ radiation was used for this.
  • the quantitative determination was carried out using a Rietveld program (Refine ++).
  • the detection limit was 0.8 mass% Si 2 N 2 O.
  • the oxygen content was determined using the hot gas extraction method.
  • the error was ⁇ 0J mass%.
  • the SiO 2 content was calculated from the oxygen content.
  • the porosity was determined on polished sections (preparation according to Practical Metallography, 27 (1990, 503-513)) at an enlargement of 1,000 using automatic image analysis (Quantiment 570). The area fraction of the pores in the cut was equated to the volume fraction. In parallel, the density was determined using a buoyancy method in accordance with EN 993-1.
  • V comparative example
  • E example according to the invention

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Abstract

Die vorliegende Erfindung betrifft neue Sinteradditive SiO2 enthaltende Siliciumnitridwerkstoffe, ein Verfahren zu deren Herstellung und deren Verwendung.

Description

Sinteradditive und SiO?-enthaltende Siliciumnitrid erkstoffe, ein Verfahren zu deren Herstellung und deren Verwendung
Die vorliegende Erfindung betrifft Sinteradditive und Siθ2-enthaltende Silicium- nitridwerkstoffe, ein Verfahren zu deren Herstellung und deren Verwendung.
Keramische Werkstoffe finden immer breiteren Einsatz im Geräte- und Apparatebau - insbesondere in Lagern (Ceramic Airframe Bearings: Lubrications Engeneering, 31 (1975), 558-564). Dabei haben sich vollkeramische Lager besonders im Bereich der Mangelschmierung und in korrosiven Medien bewährt. In den verschiedensten Einsatzbereichen für Komponenten aus Hochleistungskeramik hat sich aber gezeigt, daß sie degradieren und eine zuverlässige Lebensdauervorhersage nicht möglich ist. Der Korrosionswiderstand ist dabei in erheblichem Maße von der Art des angreifenden Mediums, der Werkstoffzusammensetzung und der überlagerten mechanischen Beanspruchung abhängig. Die Ursache dafür liegt in dem unterschiedlichen Reaktionsverhalten der einzelnen Gefügekomponenten der Keramiken (Matrixkörner, Korngrenzenphasen, Verunreinigungen) gegenüber Säuren, Basen oder unter hydrothermalen Bedingungen. Dabei zeigen flüssigphasengesinterte Werkstoffe wie Siliciumnitrid oder Siliciumcarbid (LPSSIC), die 5 bis 20 Vol.-% Korngrenzenphase enthalten, in Säuren und Basen einen Angriff entlang der Korngrenzenphase. Generell ist der Hauptangriffspunkt bei der Säure- und Laugekorrosion im Temperaturbereich <180°C die Korngrenzenphase. Diese wird aber nicht vollständig herausgelöst, was dadurch deutlich wird, daß auch Werkstoffe, die bis zum Zentrum durchkorrodiert sind, noch Festigkeiten um 300 bis 400 MPa aufweisen.
Die Korrosionsraten bei der Korrosion im sauren Bereich sind stark von der Werkstoffzusammensetzung abhängig. Aus EP-A 649 824 ist bekannt, daß MgO/Al2θ3- haltige Werkstoffe eine gute Säurebeständigkeit aufweisen, ohne daß die Ursache für dieses Verhalten vollkommen bekannt ist. Ein Weg zur weiteren Verbesserung der
Säurebeständigkeit von Siliciumnitridwerkstoffen mit Seltenerdoxiden, Y2O3 und gegebenenfalls Al2O3 als Sinteradditive ist die Reduzierung der Menge dieser Sinteradditive. Die dadurch verbesserte Korrosionsbeständigkeit muß allerdings durch höhere Aufwendungen bei der Herstellung erkauft werden, da zur Verdichtung die HIP-Technologie gebraucht wird (EP-A 414 383). Aus Mater. Res. Soc. Symp. Proc. 287 (1993) und Key Engeneering Materials 113 (1996), S. 227-237 ist weiterhin bekannt, daß es bei sehr hohen Konzentrationen von Säuren zu einer Verringerung der Korrosion kommt, was im Fall der Phosphorsäure durch die Ausbildung einer Passivierungsschicht erklärt werden konnte, siehe Corrosion of High Performance Ceramics; Springer Verlag, Berlin, 1992; S. 76 bis 78.
Es bestand daher ein großer Bedarf an säurestabilen keramischen Werkstoffen.
Aufgabe der Erfindung war daher die Bereitstellung von keramischen Werkstoffen auf Basis von Si3N4, die eine hohe Korrosionsbeständigkeit, d.h. z.B. eine geringe Masseänderung und geringe Festigkeitsverluste nach Säurebehandlung aufweisen.
Es wurde nun gefunden, daß ein Siliciumnitridwerkstoff, unabhängig von der Art seiner Herstellung eine hohe Korrosionsbeständigkeit gegenüber Säuren aufweist, wenn ein möglichst hoher Gehalt an SiO2 realisiert wird und eine Bildung von Sili- ciumoxidnitrid vermieden wird, d.h. wenn das Molverhältnis des Siliciumdioxids in der Korngrenzenphase zu den Sinteradditiven einschließlich SiO2 in der Korngrenzenphase >60 % sowie der Oxidnitridgehalt (Si2N O-Gehalt) <1 % ist.
Gegenstand der Erfindung sind daher Sinteradditive und SiO2 enthaltende Silicium- nitridwerkstoffe, deren Molverhältnis des Siliciumdioxids in der Korngrenzenphase zu den Sinteradditiven einschließlich SiO in der Korngrenzenphase >60 %, vorzugsweise >65 %, sowie der Oxidnitridgehalt (SiO2N2O) <1 % ist.
Als Sinteradditive werden die zugegebenen Stoffe verstanden, die während der Sinterung die flüssige Phase bilden und in der Korngrenzenphase verbleiben. Die Korngrenzenphase in Siliciumnitridwerkstoffen entsteht durch Erstarren der bei der Sinterung vorhandenen flüssigen Phase. Sie enthält die Sinteradditive, Silicium- dioxyd und zum Teil gelöstes Siliciumnitrid. Je nach Bedingungen der thermischen Behandlung (Abkühlgeschwindigkeit usw.) ist sie amorph oder teilkristallin. In der Regel benetzt sie die Siliciumnitridpartikel und bildet ein dreidimensionales
Netzwerk.
Sinteradditive der Korngrenzenphase im Sinne der Erfindung sind dabei vorzugsweise Y2O3, Sc O3, Seltene Erdoxide, Erdalkalioxide und Al2O3.
Die Menge der zugesetzten Sinteradditive + SiO wird vorzugsweise so gewählt, daß der Anteil an Korngrenzenphase im gesinterten Werkstoff < 20 Vol-%, besonders bevorzugt 0,1 - 17 Vol-%, ganz besonders bevorzugt 3 bis 15 Vol-%, beträgt.
In einer Ausfuhrungsform der Erfindung weisen die Silciumnitrid Werkstoffe weitere
Additive auf.
Solche Additive sind z.B. reaktive Additive, d.h. solche, die mit Si3N reagieren und SiO2 bilden, wie TiO2, WO3 und/oder MoO3. So reagiert TiO2 z.B. zu TiN, während z.B. WO3 und MoO3 Silicide bilden unter gleichzeitiger Oxidation von Si3N zu
SiO2.
Ebenfalls können auch solche Additive zugesetzt werden, die als Dispersionsphasen erhalten bleiben, wie z.B. SiC, TiN, MoSi2, TiCN und/oder HfO2 oder aber auch mit dem Si3N4 Mischkristall-bildende Zusätze, wie A1N.
Die Additive, die mit Si3N4 reagieren und SiO bilden sind vorzugsweise in einer Menge von 0 bis 10 mol-%, vorzugsweise <5 mol-%, bezogen auf Si3N4, vorhanden.
Die als Dispersionsphase erhalten bleibenden Additive sind vorzugsweise in einer
Menge von 0 bis 30 Vol-% enthalten. Mischkristallbildende Zusätze sind vorzugsweise in Mengen von 0 bis 50 mol-%, vorzugsweise <15 mol-%, bezogen auf Si3N4 vorhanden.
In einer bevorzugten Ausführungsform der Erfindung ist die Porosität des Werkstoffes <2 %.
Gegenstand der Erfindung ist zudem ein Verfahren zur Herstellung des erfindungsgemäßen Werkstoffes, wonach entweder alleine oder in Kombination
a) das eingesetzte Si3N4-Pulver alleine oder zusammen mit den Sinteradditiven und gegebenenfalls weiteren Additiven thermisch oxidiert wird oder
b) das Si3N4-Pulver alleine oder zusammen mit den Sinteradditiven und gegebe- nenfalls weiteren Additiven während der Mahlung tribooxidiert wird oder
c) das Si3N4-Pulver vor oder während der Mahlung mit Sinteradditiven oder mit SiO2 oder mindestens einer SiO2-bildenden Komponente
versetzt wird.
Für die Verfahren nach a), b) und c) kann jedes handelsübliche Si3N4-Pulver eingesetzt werden.
Die thermische Oxidation a) erfolgt dabei in einer oxidierenden Atmosphäre, vorzugsweise in Luft, O2 und/oder Wasserdampf bei Temperaturen von 300 bis 1400°C. Bei der Variante a) kann auch ein Mahlschritt vor- oder nachgeschaltet sein.
Die Tribooxidation b) während der Mahlung erfolgt durch intensive Mahlung des Si3N -Pulvers trocken oder in einer Flüssigkeit, wie H2O, einem organischen
Lösungsmittel, wie z.B. Aceton, Hexan oder Alkohol. Das Mahlen wird vorzugsweise in Kugelmühlen durchgeführt und zwar solange, bis das gemahlene Si3N4 eine mittlere Teilchengröße (d50-Wert), vorzugsweise gemessen mit dem Master Sizer S < 2,5 μm, bevorzugt < 1 μm ist, und diese das geforderte Molverhältnis von SiO2 zu Sinteradditiven aufweist.
Bei der Variante c) können als SiO2-bildende Komponente Siloxane, Silane, Siliconharze (siehe Material Science and Technology Vol. 178, Processing of Ceramics, VCH, Weinheim, (1996) Part II, 4-47, DE-A 43 18 974, EP-A 0 412 428, sowie die beschriebenen reaktiven Additive, wie z.B. TiO2, WO3 und MoO3 eingesetzt werden.
Die Menge an SiO2-bildenden Komponenten ist abhängig vom gewünschten SiO - Gehalt des Sinterformkörpers.
Die Herstellung des Sinterwerkstoffes aus den nach den Varianten a), b) und/oder c) erhalten Pulvermischungen erfolgt vorzugsweise gemäß der allgemein üblichen keramischen Technologie.
Durch den Einbau der Sinteradditive oder der mischkristallbildenden Zusätze und/oder SiO2 in das Siliciumnitridkristallgitter kann auch das Verhältnis von SiO2 zu den Sinteradditiven beeinflußt werden. In diesem Falle ist bei der Bestimmung des SiO2/Sinteradditiwerhältnisses der aAnteil der ursprünglichen Sinteradditive bzw. SiO2, um den in das Kristallgitter eingebauten aAnteil zu verringern. Das spielt insbesondere eine Rolle bei den α'- und ß'-SiAlONen, z.B. nach folgender
Gleichung:
z/2 SiO2 + zAIN + (2-1/2 z) Si3N4 → Si6.zAlz OzN8.z mit Z = O - 4,2
Dies ist bei der Berechnung der Einwaage zu berücksichtigen. Gegenstand der Erfindung ist zudem die Verwendung der erfindungsgemäßen Werkstoffe im Geräte und Apparatebau, insbesondere in Lagerungen.
Die nachfolgenden Beispiele dienen der Erläuterung der Erfindung, ohne dabei limitierend zu wirken.
Ausführungsbeispiele
Beispiel 1
Si3N4-Pulver (Baysinid®, erhältlich bei der Firma Bayer AG) Y2O3 (grade fine, erhältlich bei der Firma H.C. Starck) und Al2O3-Pulver (AKP-50®, erhältlich bei der Firma Sumitomo) und TiO2 (P25, erhältlich bei der Firma Degussa) werden entsprechend der in der Tabelle 1 angegebenen Zusammensetzung gemischt, in einer Rühr- werkskugelmühle 3 h in wäßriger Suspension homogenisiert, sprühgetrocknet und zu Körpern von 50 x 60 x 8 mm gepreßt. Die Teilchengröße (d50-Wert) des Versatzes nach der Homogenisierung betrug 0,5 μm, gemessen mit dem Master Sizer S bei pH 11,0. Die Körper werden bei 600°C 1 h an der Luft ausgeheizt. Sie werden bei 1830°C 1,5 h bei 50 bar N2 gasdruckgesintert. Die Gewichtsverluste der Proben betrugen <0,3 bis 1,8 %, abhängig vom TiO2-Gehalt des Versatzes. Die gesinterten Proben werden in Prüfstäbe zerschnitten und geschliffen.
Der Versatz 1 b wurde 6 h mit höherer Umdrehungszahl gemahlen, um den Sauer- stoffgehalt zu erhöhen.
Beispiel 2
Das Beispiel wurde analog Beispiel 1 hergestellt. Die Besonderheiten sind im weiteren beschrieben.
Die Beispiele 2a und 2b wurden analog Beispiel lb aufbereitet.
Die Sinterung des Beispiels 2a erfolgte in einem BN-beschichteten Grafittiegel in einem BN-Pulverbett. Der Gewichtsverlust betrug 1,8 %. Im Beispiel 2b wurde die Probe in einem RBSN Tiegel gesintert. Der Gewichtsverlust betrug 0,2 %. Im Beispiel 2c wurde zusätzlich 1,5 % Silikonharz als Binder verwendet. Die Beispiele 2e und 2f wurden aus plasmachemisch hergestelltem Siliciumnitridpulver mit einer Oberfläche von 60 m2/g und einem SiO2-Gehalt von 8 % hergestellt. Die Proben wurden bei 1800°C heißgepreßt.
Beispiel 3
Die Probekörper wurden analog Beispiel 1 hergestellt. Die Verdichtung erfolgte durch ein Sinter-HIP- Verfahren, wobei durch den RBSN-Tiegel und ein hohes Probenvolumen Nutzvolumenverhältnis der Gewichtsverlust auf <1,5 % reduziert wurde.
Beispiel 4
Die Probekörper wurden analog Beispiel 2 hergestellt.
Beispiel 5
Die Probekörper wurden analog Beispiel 1 hergestellt, die Sinterung erfolgte bei 1800°C.
Die jeweiligen Ergebnisse sind in Tabelle 1 aufgelistet. Exemplarisch finden sich die bei der Prüfung der Korrosionsbeständigkeit aufgetragenen Masseverluste der Beispiele 1-4 in AbbJ
Zur Bestimmung der in Tabelle 1 aufgeführten Daten wurden folgende Meßmethoden benutzt:
Aus den gesinterten Körpern wurden Biegebruchstäbe 3 x 4 x 50 mm herausge- schnitten und zur Bestimmung der mechanischen Eigenschaften und des Korrosions- verhaltens genutzt. Die Festigkeit wurde mittels 4 Punkt Methode (Auflageabstand 20/40 mm) bestimmt.
Das Korrosionsverhalten wurde in thermostatierten Glasbehältern mit 1 N Säure bestimmt. Das Säure/Feststoffverhältnis war >200 ml/ 10 g Proben. Alle 100 h wurde die Säure gewechselt. Der Masseverlust der Proben wurde durch periodische Wägung nach definierten Zeitabschnitten bestimmt (siehe Δm in Tab. 1). Die Proben wurden vor der Wägung mit H2O-dest. gespült und getrocknet.
Der Gehalt an Oxidnitrid wurde an den Proben mittels XRD Messungen bestimmt.
Dazu wurde CuKα-Strahlung verwendet. Die quantitative Bestimmung erfolgte mittels eines Rietveld-Programmes (Refine++). Die Nachweisgrenze lag bei 0,8 Masse% Si2N2O.
Der Sauerstoffgehalt wurde mittels Heißgasextraktionsmethode bestimmt. Der Fehler betrug <0J Masse%. Aus dem Sauerstoffgehalt wurde der SiO2-Gehalt berechnet.
Die Porosität wurde an polierten Schliffen (Präparation entsprechend Practical Metallography, 27 (1990, 503-513)) bei einer Vergrößerung von 1 000 mittels automatischer Bildanalyse (Quantiment 570) bestimmt. Der Flächenanteil der Poren im Schliff wurde dabei dem Volumenanteil gleichgesetzt. Parallel dazu erfolgte die Dichtebestimmung mittels Auftriebsmethode, gemäß EN 993-1.
Tabelle 1 Zusammensetzungen und Korrosionsverhalten der Werkstoffe
Figure imgf000012_0002
V = Vergleichsbeispiel; E = erfindungsgemäßes Beispiel
Figure imgf000012_0001
2a Masseverlust beim Sintern 1 ,6 %; 2b Masseverlust beim Sintern 0,2 % x in der Korngrenzenphase
Kommentierung der Ergebnisse:
Der Werkstoff gemäß EP-A 649 824 wurde in Beispiel 1 nachvollzogen, ohne den Sauerstoffgehalt zu kontrollieren und zeigt unter unseren Bedingungen einen Masse- verlust von 8,5 mg/cm2. Bei einer Einstellung des SiO2 Gehaltes kommt es zu einer
Verbesserung des Korrosionsverhaltens bei nominell gleichen Werkstoffen um Faktor 30 (wie die Beispiele la und lb zeigen). Wie wichtig die Kontrolle des Sauerstoffgehaltes nicht nur bei der Versatzherstellung ist, zeigt der Vergleich der Beispiele 2a zu 2b und 2c. Während es im Beispiel 2a zu einem hohen Gewichtsverlust beim Sintern kommt, der den Gehalt an SiO2 im gesinterten Werkstoff drastisch reduziert, zeigen Proben, die unter kontrollierten Bedingungen gesintert wurden und einen geringen Gewichtsverlust aufweisen (2b und 2c), das angestrebte günstige Korrosionsverhalten.
Es zeigt sich, daß der hohe SiO2-Gehalt zu einer Veränderung der Korrosionskinetik führt. Während bei herkömmlichen Werkstoffen bis in Korrosionsschichtdicken von mehreren 100 μm ein lineares Zeitgesetz zwischen Korrosionsschichtdicke und Reaktionszeit gilt, kommt es in den erfindungsgemäßen Werkstoffen zu einer Passivierung schon nach wenigen μm Reaktionstiefe (Abb. 2). Diese Passivierung tritt um so schneller ein, je geringer der Additivgehalt und je geringer die Korngröße der Siliciumnitridkörner im Werkstoff sind.

Claims

Patentansprüche
1. Sinteradditive und SiO2 enthaltende Siliciumnitridwerkstoffe, dadurch gekennzeichnet, daß das Molverhältnis des Siliciumdioxides in der Korngrenzenphase zu den Sinteradditiven einschließlich SiO2 in der
Korngrenzenphase >60 % sowie der Oxidnitridgehalt <1 % ist.
2. Verfahren zur Herstellung von Siliciumnitridwerkstoffen nach Anspruch 1, dadurch gekennzeichnet, daß entweder alleine oder in Kombination
a) das eingesetzte Si3N -Pulver alleine oder zusammen mit den Sinteradditiven thermisch oxidiert wird,
b) das Si3N4-Pulver alleine oder zusammen mit den Sinteradditiven und gegebenenfalls weiteren Additiven während der Mahlung tribooxidiert wird, und/oder
c) das Si3N4-Pulver vor oder während der Mahlung mit Sinteradditiven mit mindestens einer SiO2-bildenden Komponente oder SiO2 versetzt wird.
3. Verwendung der Siliciumnitridwerkstoffe nach aAnspruch 1 im Geräte- und Apparatebau, insbesondere in Lagerungen.
PCT/EP1998/006375 1997-10-20 1998-10-07 SINTERADDITIVE UND SiO2-ENTHALTENDE SILICIUMNITRIDWERKSTOFFE, EIN VERFAHREN ZU DEREN HERSTELLUNG UND DEREN VERWENDUNG Ceased WO1999020579A1 (de)

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AU97491/98A AU9749198A (en) 1997-10-20 1998-10-07 Silicon nitride substances containing sintering additives and sio2, method for producing them and use of the same
EP98951501A EP1025062A1 (de) 1997-10-20 1998-10-07 Sinteradditive und siliciumdioxid-enthaltende siliciumnitridwerkstoffe, ein verfahren zu deren herstellung und deren verwendung
US11/583,560 US7244686B2 (en) 1997-10-20 2006-10-19 Bearings produced from silicon nitride substances containing sintering additives and SiO2

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JP6960636B2 (ja) * 2016-09-27 2021-11-05 北陸成型工業株式会社 プラズマ処理装置用炭化ケイ素部材及びその製造方法
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4517037A (en) * 1981-11-02 1985-05-14 Aluminum Company Of America Refractory composition comprising nitride filler and colloidal sol binder
EP0649824A2 (de) * 1993-10-25 1995-04-26 Kabushiki Kaisha Toshiba Auf Siliziumnitrid basierende Sinter

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3836374A (en) * 1972-01-20 1974-09-17 Norton Co Hot pressed silicon nitride
US4607017A (en) * 1985-06-20 1986-08-19 Gte Products Corporation Silicon nitride based cutting tool
US4826791A (en) * 1987-05-29 1989-05-02 Kennametal Inc. Silicon carbide-alpha prime sialon beta prime sialon
JPH06102576B2 (ja) * 1988-02-27 1994-12-14 日本碍子株式会社 高緻密窒化珪素焼結体およびその製造方法
JP2755702B2 (ja) 1989-07-27 1998-05-25 株式会社東芝 耐摩耗性部材
DE3926077A1 (de) 1989-08-07 1991-02-14 Peter Prof Dr Greil Keramische verbundkoerper und verfahren zu ihrer herstellung
DE4038003C2 (de) * 1990-11-29 1997-01-02 Bayer Ag Verfahren zur Herstellung von Sinterwerkstoffen auf Si¶3¶N¶4¶-Basis
EP0493802B1 (de) * 1990-12-27 1996-08-28 Kyocera Corporation Siliciumnitrid-Siliciumcarbid gesinterter Verbundwerkstoff
FI923583L (fi) * 1991-08-12 1993-02-13 Sturm Ruger & Co Haevarmsarrangemang i automatpistol foer att inrikta slagstiftet och foeraoteruppspaenning
EP0587119B1 (de) * 1992-09-08 1998-01-07 Kabushiki Kaisha Toshiba Siliciumnitrid-Sinterkörper mit hoher Wärmeleitfähigkeit und Verfahren zu seiner Herstellung
US5312785A (en) * 1993-05-18 1994-05-17 The Dow Chemical Company Sintered self-reinforced silicon nitride
DE4318974C2 (de) 1993-06-08 1995-04-27 Fraunhofer Ges Forschung Verfahren zur Herstellung von Formkörpern
US5523268A (en) * 1993-12-22 1996-06-04 Kabushiki Kaisha Toyota Chuo Kenkyusho Silicon nitride sintered body
US5508241A (en) * 1994-03-22 1996-04-16 Saint Gobain/Norton Industrial Ceramics Corp. Silicon nitride bearing ball having a high rolling contact fatigue life
DE19519864B4 (de) * 1994-05-31 2006-11-23 Kyocera Corp. Siliciumnitridsinterprodukt und Verfahren zu seiner Herstellung
EP0740311B1 (de) * 1995-04-24 1999-11-10 Kyocera Corporation Dielektrisches Material mit niedrigem dielektrischem Verlust für Hochfrequenzanwendungen
DE19546238A1 (de) * 1995-12-12 1997-06-19 Sueddeutsche Kalkstickstoff Verfahren zur Herstellung von gesinterten Siliciumnitrid
JPH1179848A (ja) * 1997-08-29 1999-03-23 Kyocera Corp 窒化珪素質焼結体

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4517037A (en) * 1981-11-02 1985-05-14 Aluminum Company Of America Refractory composition comprising nitride filler and colloidal sol binder
EP0649824A2 (de) * 1993-10-25 1995-04-26 Kabushiki Kaisha Toshiba Auf Siliziumnitrid basierende Sinter

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