EP0952968A1 - Ceramiques frittees a base de al 2?o 3? et renforcees par une substance dure et procede de production correspondant - Google Patents

Ceramiques frittees a base de al 2?o 3? et renforcees par une substance dure et procede de production correspondant

Info

Publication number
EP0952968A1
EP0952968A1 EP97950119A EP97950119A EP0952968A1 EP 0952968 A1 EP0952968 A1 EP 0952968A1 EP 97950119 A EP97950119 A EP 97950119A EP 97950119 A EP97950119 A EP 97950119A EP 0952968 A1 EP0952968 A1 EP 0952968A1
Authority
EP
European Patent Office
Prior art keywords
hard material
hard
phase
al2θ3
reinforced
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
EP97950119A
Other languages
German (de)
English (en)
Inventor
Andreas Krell
Lutz-Michael Berger
Ekhart Langholf
Paul Blank
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.)
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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 Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Publication of EP0952968A1 publication Critical patent/EP0952968A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • C04B35/117—Composites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B27/00—Tools for turning or boring machines; Tools of a similar kind in general; Accessories therefor
    • B23B27/14—Cutting tools of which the bits or tips or cutting inserts are of special material
    • B23B27/148—Composition of the cutting inserts
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • C04B35/117—Composites
    • C04B35/119—Composites with zirconium oxide

Definitions

  • the invention relates to the field of ceramics and relates to dense, hard-reinforced Al2 ⁇ 3 sintered ceramics of the type Al2 ⁇ 3 / TiC x NyO z , as are used, for example, as wear-resistant parts in bearings of all kinds, as cutting tools, as abrasives or for magnetic head substrates in data storage devices can and a process for their preparation.
  • the addition of 5-15% T1O2 to such compositions is said to have a sintering requirement according to US Pat. No. 4,356,272 (without the T1O2 forming a connection with the hard material phase, for example in the sense of the formation of an oxycarbide phase), but the result is the resulting structure is described with the grain size statements D ⁇ 4 ⁇ m and is therefore certainly not more fine-grained than in the example cited above.
  • a mixed ceramic based on AI2O3 + 0.5 - 40% T ⁇ (C, N) with a structure, as it is sometimes called "nano" composite, is known from EP 414 910 B1, according to which the addition of 10-40% SiC whis core is required (which causes problems on the part of the manufacturer due to the carcinogenic effect of the whiskers)
  • carbonite particles of the size ⁇ 100 nm are enclosed in the intragranular manner in Al2 ⁇ 3 particles, which in turn are smaller than 1 ⁇ m, while on the one hand being one of the first Work that describes a real submicrometer mixed ceramic in which both microstructure components with grain sizes of less than 1 ⁇ m are present, the value usable on the property side is questionable, astonishing no hardnesses communicated
  • the nitrogen also prevents the use of the fine-grained structure in the sense of high hardnesses
  • Al2 ⁇ 3 / hard-material ceramic with real, intergranular submicron microstructures have been produced in recent years by combining very special metal C x NyO z vanants, preferably in the carbonitridic range, with increasingly complex doping and at the same time drastically reducing the powder grain size of the hard material.
  • hot isostatic pressing was almost always introduced into the technological process and an optimal one mutual coordination of the pre-sintering conditions (generally without pressure in argon for 30 to 90 min at temperatures around 1700 - 1850 ° C) and the subsequent isostatic pressure sintering (usually around 1400 ° C) are described as essential for the production of extremely fine-grained structures. According to US Pat. No.
  • Al2 ⁇ 3 / hard material structures with a submicron structure can be found in EP 443 624 A1.
  • Typical grain sizes are 0.5 - 0.9 ⁇ m (always ⁇ 1 ⁇ m) for the Al2 ⁇ 3 phase, 0.4 - 0.6 ⁇ m (always ⁇ 0.6 ⁇ m) for the hard material phase. These structures are obtained by presintering and hot isostatic post-compression of mixtures of the composition
  • AI2O3 including a doping-related solid solution of 0.1 -12% of oxides of the elements Y, Mg, Cr, Ni, Co, rare earths
  • the hard material must not show any significant sub-stoichiometry: 0.95 ⁇ (x + y + z) ⁇ 1 is required.
  • the invention is based on the object of specifying dense, hard-reinforced AI2O3 sintered ceramics which have a submicron structure for each individual phase
  • the hard material-reinforced Al2 ⁇ 3 sintered ceramics with a relative density of> 98.5% have homogeneous, predominantly intergranularly structured dispersion structures which contain
  • the proportion of the hard material phase is 30-50% by volume.
  • the proportion of the hard material phase is 5-30% by volume.
  • the object is further achieved by a process for the production of hard-reinforced Al2 ⁇ 3 sintered ceramics according to claim 1, in which the powdered starting materials are mixed together in a liquid medium, a hard material powder having an average grain size of> 2 ⁇ m and a specific surface area of ⁇ 3 m ⁇ / g is used
  • the object is also achieved by a process for producing hard-reinforced Al2 ⁇ 3 sintered ceramics according to claim 2, in which the powdery starting materials are mixed-mixed together in a liquid medium, a hard material powder having an average grain size of> 2 ⁇ m and a specific surface area of ⁇ 3 m 2 / g is used and an AI2O3 starting powder with impurities ⁇ 1% by mass is used and powdered starting materials are used, the proportion of which, expressed as metal oxide, is ⁇ 1% by mass based on the total offset
  • powdery starting materials which contain a component of 2-10 mass% T1H2
  • a hard material powder with a free carbon content of ⁇ 0.15% by mass is used as the starting material in powder form
  • the object is achieved by a process for the production of hard-reinforced Al2 ⁇ 3 sinter ceramic with a relative density of> 98.5% and homogeneous, predominantly intergranularly structured dispersion structures which contain
  • a homogeneous, predominantly intergranularly structured dispersion structure is understood to mean a spatial phase distribution that excludes vermicular structures, as described above in connection with a reactive-exothermic structure, as well as a predominantly intragranular occurrence of the hard material phase within closed corundum particles (or vice versa) Structures according to the invention instead have a predominantly intergranular character with homogeneous spatial distribution of the phases. Since the known state of the art does not adequately define the term grain size of such hard-reinforced, essentially two-phase mixed ceramics, because the so-called "grain" size mostly on polished and unetched cuts is determined and thus only the boundaries of single-phase areas, but not their inner Taking into account the grain boundaries of the individual crystallites, the following definition is to be used here.
  • the average size of the individual AI2O3 and hard material crystallites is generally smaller than the "comm" size defined in this way is (which is actually better had to be referred to as the size of the single-phase area, but this is uncommon)
  • transmission electron microscopic investigations have shown that for low-agglomeration Al2 ⁇ 3 / hard material mixing ceramics with average grain sizes ⁇ 3 ⁇ m, the single-phase partial areas of the hard material phase are only rarely composed of several crystals, essentially representing individual crystallites The "true" hard material grain size is therefore only a little smaller than the grain size determined according to the 0 g regulation.
  • the invention is based on the surprising finding that, in contrast to the prior art described, a high proportion of oxygen in cubic hard material phases based on titanium in no way leads to an extraordinarily strong (“excessive") growth of the hard material crystallites and does not adversely affect hardness if certain material Conditions are adhered to, such behavior is apparently linked to special compositions, for example to the frequent doping of the ceramics with diffusion-demanding oxides (EP 443 624 A1).
  • the fine-grained structure is a "value in itself" due to the optimized micro-breakout behavior of the grains during grinding, polishing and use, the hardness is also of decisive importance for the use as a tool or wear material.
  • a further embodiment of the invention is aimed at these applications, in which the submicron structure additionally has a high hardness HV10> 2100
  • compositions of the hard material phase were found with which mixed ceramics with a density of at least 98.5% despite the absence of extremely fine-grained hard material powders and sintering-causing oxidic doping or on Ti and TiH2 additives even at low enough temperatures for the realization of submicrometer structures, if the ceramics contain high hard material contents of 30 - 50 vol.% (the so-called approx.
  • compositions with only 5 - 30% by volume of hard material require even higher sintering temperatures than hard material-free sintered corundum, but the effect of the hard material particles which inhibits the grain growth of the corundum crystallites naturally becomes weaker as the hard material concentration decreases.
  • the ceramics known from the prior art there is therefore an increased crystallite growth of the Al 2 O 3 phase under the conditions mentioned during sintering. It is therefore a further surprising finding that the compositions according to the invention enable the production of fine-grained structures in which each of the phases shows an average grain size of ⁇ 1 ⁇ m even for lower hard material contents in the range from 5 to 30% by volume.
  • Hard material compositions with a higher oxygen content in the range 0.10 ⁇ z ⁇ 0.50 are particularly conducive to achieving the objectives of the invention.
  • the sintering activity of the phase mixtures achieved with the compositions according to the invention is so high that submicrometer structures with a relative density> 98.5% can be produced by a process which, as a special feature, produces a mixture by mixing the powdered raw materials together in a liquid medium, whereby the hard material powder used has an average grain size of> 2 ⁇ m and a specific surface area ⁇ 3 m ⁇ / g. It goes without saying that the product objectives of the invention can also be achieved with more fine-grained hard material powders of the composition according to the invention, but this causes unnecessarily higher costs.
  • the usability of hard material powders whose average grain size is considerably above the average grain size of the hard material phase in the sintered structure, cannot be explained solely by a surprisingly high sintering activity of the compositions according to the invention, which is bound to the atomic defect structure.
  • the hard material compositions according to the invention also have a surprisingly high tendency to comminute when mixed grinding with the corundum raw material, comparable perhaps to the known high brittleness of TiH2 and clearly differentiated from the relatively high toughness of non-inventive hard material phases such as TiC or Ti (C, N).
  • the proportion of impurities in the Al2 ⁇ 3 starting material used is less than 1% by mass
  • a finely dispersed titanium dioxide and a technical carbon, preferably carbon black are intimately mixed with one another.
  • the molar ratio of the mixture is in the range from 1 1 to 1 2.9, but preferably in the range from 1 2 to 1 2.9.
  • the mixture is mixed in an oven Graphite heating elements brought to reaction
  • the reaction takes place in two stages, whereby the powder can be cooled to room temperature between the two stages.
  • the first reaction stage takes place under a reducing or inert atmosphere, which can also contain nitrogen.
  • the reaction is carried out in this stage to such an extent that a single-phase cubic Reaction product arises
  • the annealing takes place under reducing atmosphere or preferably under vacuum.
  • the hard material powder according to the invention is formed with an oxygen content of z> 0.10 or z> 0.05 combined with a clear substoichiometry (x + y + z) ⁇ 0.95.
  • the hard material powder preferably has low contents Free carbon of ⁇ 0.15% by mass
  • the hard material powder can be subjected to a separate grinding
  • the dispersion is then subjected to a three-hour mixed grinding at a speed of 1000 rpm in a ball mill with corundum lining and Y-TZP grinding balls (ZrÜ2 with 3 mol% Y2O3) then freeze-dried
  • the Zr ⁇ 2 content of the batch caused by grinding ball abrasion is 4% by mass or 3% by volume
  • the batch, freeze-dried to a residual moisture content of ⁇ 2%, is passed through a 300 ⁇ m sieve and uniaxially pressed to shaped bodies at 200 MPa
  • the TiCrj sOrj 1 powder used was prepared by weighing 216 g of T1O2 and 84 g of carbon black (corresponding to a molar ratio of 1 2.6) and pre-homogenizing in a polyethylene bottle for 30 minutes on a roller mixer. The subsequent mixed grinding was carried out dry in a Ball mill in stainless steel containers with hard metal balls with a mass ratio of 15 for 15 hours. The powder mixture was then annealed in an oven with graphite heating elements in graphite crucibles in partial quantities of 30 g each.
  • the annealing was carried out at a heating rate of 50 K / min from room temperature to 1500 ° C and 20 K / min in the range of 1500 - 1600 ° C under an argon flow of 100 l / min
  • the argon flow was interrupted and evacuated during an isothermal hold time of 15 min in the furnace chamber and the pressure was at the end of the hold time 8.5 x 10 "2 MPa
  • the pressure was 5.5 x 10 ⁇ 5 MPa.
  • the sample was quickly cooled by lowering the graphite crucible into the cooling chamber.
  • the hard material memever obtained was comminuted in a disk vibrating mill for 30 s at 1400 rpm.
  • the chemical analysis The composition gave T1C0 75O0 11 with a free carbon content of 0.12% by mass.
  • the lattice parameter was determined to be 0.4318 nm.
  • the average grain size was approx. 4 ⁇ m with a specific surface area of 0.97 m 2 / g
  • the moldings are fired for one hour at 800 ° C in hydrogen to drive off the organic pressing aid, the density which is subsequently determined is 2.51 g / cm 3 and thus 58% of the theoretical density. Then a relative one in argon is sintered at 1700 ° C for one hour Density of 95%, combined with almost exclusively closed residual porosity, achieved. The subsequent hot isostatic post-compression (1435 ° C / 2 h / N2-120 MPa) results in a relative sintered density of more than 99.5%. Additional examinations show that the organic pressing aids optionally in H2, Ar or also in N2 can take place and that for hot isostatic pressing N2 and Ar atmospheres lead to results that do not differ significantly
  • ground bending fracture bars diamond grinding wheel 40/50 ⁇ m / wet grinding / infeed 0.01-0.02 mm
  • ground parts are mainly used in technical applications the dimensions 3 x 5 x 50 mm 3
  • This influence is universal in brittle materials and applies equally to oxidic materials (J Am Ceram Soc 78 [5] 1417-1419 (1995)) and to predominantly covalent materials (e.g. S13N4 J at Ceram Soc 76 [6] 1602-1604 (1993)), but with a structure-specific variation in the size of this effect
  • Oxide phase (56 vol .-% Al 2 O 3 + 3 vol .-% Zr ⁇ 2): 0.70 ⁇ m
  • Hard material phase (41 vol.%): 0.58 ⁇ m
  • Breaking strength 760 + 108 MPa.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Ceramic Products (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)

Abstract

L'invention concerne le domaine des céramiques, notamment les céramiques frittées à base de Al2O3, denses et renforcées par une substance dure, de type Al2O3/TiCxNyOz telles que celles utilisées pour les pièces résistantes à l'usure. L'invention vise à créer des céramiques frittées à base de Al2O3 et renforcées par une substance dure qui possèdent une structure submicrométrique pour chaque phase. Pour ce faire, les céramiques frittées à base de Al2O3 et renforcées par une substance dure de l'invention ont une structure contenant: une matrice de corindon avec 0 à 15 % en volume de ZrO2, et 5 à 50 % en volume d'une phase de substance dure à base de titane TiCxNyOz a) avec une proportion d'oxygène de z > 0,10 ou b) avec une proportion d'oxygène de z >/= 0,05 et une nette substoechiométrie de (x+y+z) </= 0,95 de la phase substance dure. La granulométrie moyenne de chacune des phases des structures est inférieure à 1 mu m et les structures peuvent présenter une dureté Vickers élevée de HV10 >/= 2100. L'invention concerne également un procédé selon lequel les matières premières pulvérulentes sont broyées et mélangées dans un milieu liquide.
EP97950119A 1996-11-09 1997-11-06 Ceramiques frittees a base de al 2?o 3? et renforcees par une substance dure et procede de production correspondant Ceased EP0952968A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE1996146334 DE19646334C2 (de) 1996-11-09 1996-11-09 Hartstoffverstärkte Al¶2¶O¶3¶-Sinterkeramiken und Verfahren zu deren Herstellung
DE19646334 1996-11-09
PCT/EP1997/006136 WO1998021161A1 (fr) 1996-11-09 1997-11-06 Ceramiques frittees a base de al2o3 et renforcees par une substance dure et procede de production correspondant

Publications (1)

Publication Number Publication Date
EP0952968A1 true EP0952968A1 (fr) 1999-11-03

Family

ID=7811181

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97950119A Ceased EP0952968A1 (fr) 1996-11-09 1997-11-06 Ceramiques frittees a base de al 2?o 3? et renforcees par une substance dure et procede de production correspondant

Country Status (3)

Country Link
EP (1) EP0952968A1 (fr)
DE (1) DE19646334C2 (fr)
WO (1) WO1998021161A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10103174B4 (de) * 2001-01-25 2004-07-22 Thyssenkrupp Stahl Ag Verwendung eines aus Metallpartikeln und nichtmetallischen Feststoffpartikeln hergestellten Probekörpers als Standardprobe zum Kalibrieren einer spektrometrischen Analyseeinrichtung
CN116639981B (zh) * 2023-07-27 2023-10-13 山东金鸿新材料股份有限公司 一种无压碳化硼陶瓷的制备方法
CN117700253B (zh) * 2023-12-26 2024-07-09 东莞市湃泊科技有限公司 Amb工艺陶瓷板覆铜的全流程智能制备方法及系统

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4251841A (en) * 1979-06-01 1981-02-17 International Business Machines Corporation Magnetic head slider assembly
JPS56140069A (en) * 1980-03-29 1981-11-02 Nippon Tungsten Ceramic sintered body and manufacture
DE3529265A1 (de) * 1984-08-22 1986-02-27 Ngk Spark Plug Co., Ltd., Nagoya, Aichi Keramik mit sehr hoher zaehigkeit und verfahren zur herstellung derselben
US4902651A (en) * 1986-06-20 1990-02-20 Sumitomo Special Metals, Co. Material for magnetic head substrate member
DE69015509T2 (de) * 1989-02-22 1995-05-11 Kobe Steel Ltd Aluminiumoxidkeramik, ihre herstellung und wegwerfstück daraus.
US5188908A (en) * 1990-02-23 1993-02-23 Mitsubishi Materials Corporation Al2 O3 Based ceramics
EP0540227A1 (fr) * 1991-10-29 1993-05-05 Minnesota Mining And Manufacturing Company Composé d'oxyde d'aluminium et de carbure de titane non-conducteur, son procédé de préparation et élément coulissant l'utilisant

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9821161A1 *

Also Published As

Publication number Publication date
WO1998021161A1 (fr) 1998-05-22
DE19646334C2 (de) 2001-05-31
DE19646334A1 (de) 1998-05-14

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