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EP0111584A1 - Method for preparing cermets - Google Patents

Method for preparing cermets Download PDF

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Publication number
EP0111584A1
EP0111584A1 EP82111912A EP82111912A EP0111584A1 EP 0111584 A1 EP0111584 A1 EP 0111584A1 EP 82111912 A EP82111912 A EP 82111912A EP 82111912 A EP82111912 A EP 82111912A EP 0111584 A1 EP0111584 A1 EP 0111584A1
Authority
EP
European Patent Office
Prior art keywords
cermets
preparing
ceramic
silica
aluminium
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
EP82111912A
Other languages
German (de)
French (fr)
Inventor
Felicjan Biolik
Stanislaw Serkowski
Zygmunt Morys
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.)
Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet"
Original Assignee
Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet"
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 Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet" filed Critical Biuro Projektow Przemyslu Metali Niezelaznych "Bipromet"
Priority to EP82111912A priority Critical patent/EP0111584A1/en
Publication of EP0111584A1 publication Critical patent/EP0111584A1/en
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/12—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on oxides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C22C1/1068—Making hard metals based on borides, carbides, nitrides, oxides or silicides

Definitions

  • This invention relates to a method for preparing ceramic metals on the basis of A1 2 0 3 and Si, from ceramic siliceous or silica containing products.
  • the methods for preparing cermets have been described in the book of T. Gibas "Ceramals and cermets", WNT Warszawa, 1961, pp. 206-220. Said methods consist in pressing of compacts from powdered metals and ceramic powders and in sintering them at high temperatures and in suitable atmospheres, or in simultaneous pressing and sintering thereof..
  • the described methods comprise the preparation of cermets on the basis of Al 2 O 3 - Fe, Al 2 0 3 - Cr, Al 2 O 3 - Al, A1 2 0 3 - Mo, A1 2 0 3 - Co, Al 2 O 3 - Ni, Al 2 O 3 - A g .
  • a disadvantage of known methods for preparing cermets are the high costs of their production, mainly due to the preparation of metallic powders with defined shape and size of grains, and to the process of pressing at high pressures.
  • the essence of the invention consists in that the siliceous or silica containing ceramic products are submitted to the action of a reducing agent in form of aluminium and silicon alloy in molten state, preferably of a temperature of 750°C.
  • the reducing agent according to the invention contains preferably 3-11% metallic silicon.
  • the advantages of the invention are among others the elimination of the production process of employing powdered metals, of the high-pressure pressing of compacts, and of the complicated operation of sintering of compacts, very good physical and chemical properties of cermets obtained in the method according to the invention, the possibility of preparing cermets having various physical and chemical properties, depending on the chemical composition of the ceramic product.
  • the method according to the invention enables the ceramic metals of various physical and chemical properties to be obtained depending on the quantity of silica (Si0 2 ) and other components contained in a ceramic product submitted to the action of the reducing agent.
  • the ceramic metals can be prepared from every ceramic silica containing product such as chamotte, porcelain, bonded silica carbide, clay, bonded alumina, silica glass etc.
  • the reducing time depends on the quantity of silica contained in a ceramic product, the more silica the quicker reaction and the time depends on the size of compacts as well as on their density and the bigger compact the higher density and the longer reaction time.
  • the reduction process only consists in immersion of ceramic compact in molten aluminium-silicon (AlSi) alloy for 2-10 days.
  • the volume of bath is generally bigger than the volume of ceramic compacts and does not require any correction during reduction process.
  • the quicker reduction process the bigger content of silica in Al-Si alloy.
  • the cylindrical ceramic compact having the diameter of 50 mm and height of 50 mm and having the Sio 2 content of 98%, the density of 1.9 g/cm 3 , and the open porosity of 15% is immersed in molten aluminium containing 3% of silicon, at the temperature of 780°C, after preliminary heating it up to the temperature of 750°C.
  • the compact is held in molten aluminium at the temperature of 730°C for a period of 125 hours in order to enable the total reduction of silica according to the reaction
  • the outside surfaces are cleaned from possible oxide accretions, whereby the cleaning operation can be carried out on a cold, or a hot compact immediately after being removed from the bath.
  • the cermet compact obtained in this way of steely- silvery colour, has the following chemical composition and more important physical and chemical properties:
  • the cermet characterizes by very high resistance to oxidation up to the temperature of 1400°C, and by high resistance to the action of molten zinc and aluminium, and resistance to wearing.
  • the application range is very broad, it comprises among others the casings for thermoelements, crucibles for melting zinc and aluminium, heat exchangers, responsible parts of machines and installations, heating resistors.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

A method of preparing cermets from siliceous or silica-containing ceramic products by submitting these compacted products to the action of a molten alloy of aluminium and silicon, according to the reaction 3Si02 + 4AI → 3Si + 2Al2O3.

Description

  • This invention relates to a method for preparing ceramic metals on the basis of A1203 and Si, from ceramic siliceous or silica containing products.
  • The methods for preparing cermets, known hitherto, have been described in the book of T. Gibas "Ceramals and cermets", WNT Warszawa, 1961, pp. 206-220. Said methods consist in pressing of compacts from powdered metals and ceramic powders and in sintering them at high temperatures and in suitable atmospheres, or in simultaneous pressing and sintering thereof.. The described methods comprise the preparation of cermets on the basis of Al2O3 - Fe, Al203 - Cr, Al2O3 - Al, A1203 - Mo, A12 0 3 - Co, Al2O3- Ni, Al2O3 - Ag.
  • A disadvantage of known methods for preparing cermets are the high costs of their production, mainly due to the preparation of metallic powders with defined shape and size of grains, and to the process of pressing at high pressures.
  • The essence of the invention consists in that the siliceous or silica containing ceramic products are submitted to the action of a reducing agent in form of aluminium and silicon alloy in molten state, preferably of a temperature of 750°C. The reducing agent according to the invention contains preferably 3-11% metallic silicon.
  • The advantages of the invention are among others the elimination of the production process of employing powdered metals, of the high-pressure pressing of compacts, and of the complicated operation of sintering of compacts, very good physical and chemical properties of cermets obtained in the method according to the invention, the possibility of preparing cermets having various physical and chemical properties, depending on the chemical composition of the ceramic product.
  • The method according to the invention enables the ceramic metals of various physical and chemical properties to be obtained depending on the quantity of silica (Si02) and other components contained in a ceramic product submitted to the action of the reducing agent.
  • The ceramic metals can be prepared from every ceramic silica containing product such as chamotte, porcelain, bonded silica carbide, clay, bonded alumina, silica glass etc. The reducing time depends on the quantity of silica contained in a ceramic product, the more silica the quicker reaction and the time depends on the size of compacts as well as on their density and the bigger compact the higher density and the longer reaction time.
  • The reduction process only consists in immersion of ceramic compact in molten aluminium-silicon (AlSi) alloy for 2-10 days. The volume of bath is generally bigger than the volume of ceramic compacts and does not require any correction during reduction process. The quicker reduction process the bigger content of silica in Al-Si alloy.
  • During reduction ceramic compact does not change its volume but its density increases according to the given reaction.
    • Example
  • The cylindrical ceramic compact having the diameter of 50 mm and height of 50 mm and having the Sio2 content of 98%, the density of 1.9 g/cm3, and the open porosity of 15% is immersed in molten aluminium containing 3% of silicon, at the temperature of 780°C, after preliminary heating it up to the temperature of 750°C.
  • The compact is held in molten aluminium at the temperature of 730°C for a period of 125 hours in order to enable the total reduction of silica according to the reaction
    Figure imgb0001
  • After this period the compact is removed from the metal bath and slowly cooled down to the ambient temperature.
  • The outside surfaces are cleaned from possible oxide accretions, whereby the cleaning operation can be carried out on a cold, or a hot compact immediately after being removed from the bath.
  • The cermet compact obtained in this way, of steely- silvery colour, has the following chemical composition and more important physical and chemical properties:
    Figure imgb0002
  • The cermet characterizes by very high resistance to oxidation up to the temperature of 1400°C, and by high resistance to the action of molten zinc and aluminium, and resistance to wearing.
  • The application range is very broad, it comprises among others the casings for thermoelements, crucibles for melting zinc and aluminium, heat exchangers, responsible parts of machines and installations, heating resistors.

Claims (1)

  1. A method for preparing cermets characterized in that siliceous or silica containing products are submitted to the action of a reducing agent in form of aluminium and silicon alloy at molten state.
EP82111912A 1982-12-22 1982-12-22 Method for preparing cermets Ceased EP0111584A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP82111912A EP0111584A1 (en) 1982-12-22 1982-12-22 Method for preparing cermets

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP82111912A EP0111584A1 (en) 1982-12-22 1982-12-22 Method for preparing cermets

Publications (1)

Publication Number Publication Date
EP0111584A1 true EP0111584A1 (en) 1984-06-27

Family

ID=8189416

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82111912A Ceased EP0111584A1 (en) 1982-12-22 1982-12-22 Method for preparing cermets

Country Status (1)

Country Link
EP (1) EP0111584A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0116809B1 (en) * 1983-02-16 1990-05-02 MOLTECH Invent S.A. Cermets and their manufacture
WO2011146814A3 (en) * 2010-05-20 2012-05-24 Dow Corning Corporation Method and system for producing an aluminum-silicon alloy

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB392640A (en) * 1931-12-16 1933-05-25 Ernst Wydler Process for the preparation of metallic sulphides along with metals or massive silicon
GB1055231A (en) * 1964-01-20 1967-01-18 Morganite Res & Dev Ltd Improvements in or relating to the production of refractory nitride articles

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB392640A (en) * 1931-12-16 1933-05-25 Ernst Wydler Process for the preparation of metallic sulphides along with metals or massive silicon
GB1055231A (en) * 1964-01-20 1967-01-18 Morganite Res & Dev Ltd Improvements in or relating to the production of refractory nitride articles

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
COMPTES RENDUS DE L'ACADEMIE DES SCIENCES, vol. 216, 1943, pages 268-270 *
GMELIN: "Handbuch der Anorganischen Chemie, 8th edition, Verlag Chemie GmbH., Weinheim DE. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0116809B1 (en) * 1983-02-16 1990-05-02 MOLTECH Invent S.A. Cermets and their manufacture
WO2011146814A3 (en) * 2010-05-20 2012-05-24 Dow Corning Corporation Method and system for producing an aluminum-silicon alloy
CN103154288A (en) * 2010-05-20 2013-06-12 道康宁公司 Method and system for producing an aluminum-silicon alloy
US8900341B2 (en) 2010-05-20 2014-12-02 Dow Corning Corporation Method and system for producing an aluminum—silicon alloy

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19841210

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18R Application refused

Effective date: 19870522

RIN1 Information on inventor provided before grant (corrected)

Inventor name: BIOLIK, FELICJAN

Inventor name: SERKOWSKI, STANISLAW

Inventor name: MORYS, ZYGMUNT