PL158479B3 - Production method for ceramic machining tiles for tools for steel and other materials machining - Google Patents

Abstract

A method of manufacturing ceramic machining tiles for tools for machining of steel and other materials where aluminum oxide Al2O3, crystallographic form α with phase purity of 100 percent, chemical purity minimum 99.9 percent of the mass, granulation below 1 μm, and specific surface above 5m<2>/g is used as the basic raw material, additives in an amount of up to 5 percent of the mass, chosen from amongst aluminum oxides Al2O3 of all intermediate phase forms except for the α form, magnesium oxide MgO, chromium oxide Cr2O3, non-stabilized zirconium oxide ZrO2, yttrium oxide Y2O3, titanium oxide TiO2, and boron oxide B2O3, are entered as sintering facilitating agents, the tiles are sintered in an oxidizing or moist hydrogen atmosphere so that relative density of the sinter is close to 100 percent, but with abrasive grain growth limited to a maximum of 2.5 μm, measured according to a ceramographic methods, and further the tiles sintered in the said way are subjected to surface finishing, which involves the abrading the surface layer of the sinter with microfissures, and possibly applying chemically a nitride, a carbide or a nitride-oxygen-carbide coat lowering the coefficient of friction with the machined material, in accordance with patent No. 148 081, characterized in that the zirconium oxide additive is introduced into the mixture of oxides in the form of zirconium oxide gel Zr(OH)4, amorphous in X-ray photography examination, and the tiles are sintered in an oxidizing atmosphere and at a temperature between 1,970 and 1,770 degrees K for 1 to 5 hours.

Description

The present invention relates to a method of manufacturing ceramic cutting inserts for tools for processing steel and other materials, which is an improvement to the method of Patent No. 148,081.

It is known from the description of the invention, Pat. 148 081 a method for producing ceramic inserts, characterized in that the starting material used alumina Al ^ Oj & variety crystal phase purity of 100%, a chemical purity of at least ^99.9% by weight ^s, granulation ^of less than ^{1 p} I ^{p h} owierzc than in ^ł aściwej ^p o ^y descent ⁵ m / g, uL <o ^s rO ^rods to facilitate sintering of the introduced additives in an amount up to 5% by weight, selected from the oxides of aluminum intermediate variant phase outside variety ot, magnesium oxide MgO, chromium oxide C ^ Oh, ZrO zirconium oxide? unstabilized, yttrium oxide ^ 2 °} ', titanium oxide TiO, boron oxide B £ Oj, sintering of the platelets is carried out in an oxidizing atmosphere or humid hydrogen so as to obtain a relative sinter density close to 100% but with a limited medium grain growth to a maximum of 2 5 pm measured by ceramographic methods, and then the sintered plates are subjected to surface finishing treatment consisting in abrasive removal of the surface layer of the sinter with micro-cracks and possible chemical application of a nitride, carbide or carbon-oxy-nitride coating that reduces the friction coefficient with the processed material.

The essence of the solution according to the invention is that the addition of zirconium oxide Zr0 £ is introduced to the oxide mixture in the form of a gel of zirconium hydroxide Zr (OH, X-ray amorphous, which in the further technological process turns into zirconium oxide ΖΓΟ2, and the sintering of the plates is carried out in the atmosphere oxidation in the temperature range from 1970 to 1770 K for 1 to 5 hours.

The advantage of the solution according to the invention is the possibility of obtaining sinters of high density, uniform structure, good strength properties and high abrasion resistance.

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Example Mixture with the following composition:

92.5% alumina N Oh variety ot phase purity of 100%, a chemical purity of at least 99, ^9%, furan ^g ACJ ^{l and} less than ^{1 p m, and} the area clean surfaces ^ ^y descent right area of 5 m ^{Z / g}

3.0% of Alumina grade miany

0.3% magnesium oxide MgO

4.2% based on ZrO®, introduced as Zr (OH) 4 in the form of a gel, is sintered at 1940 K for 3 hours in an oxidizing atmosphere.

The obtained sinter has the following properties: relative density> 99%, average grain 2 pm, hardness HV30> 2200 bending strength 0 g 485 MPa compressive strength 1800 MPa

K and c [M By HVG and HVNM 5 - fi

By using zirconium hydroxide, a very good mass distribution is achieved by mixing in water or ethylene alcohol. During the technological process, zirconium hydroxide turns into active oxide.

158 479

Department of Publishing LJP RP. Circulation of 90 copies. Price PLN 5,000.

Claims (1)

Patent claim A method of producing ceramic cutting inserts for tools for the processing of steel and other materials, characterized by the fact that the starting material is aluminum oxide Al "0, crystallographic variety oi with 100% phase purity, chemical purity l ^J 2 minimum 99.9% by weight , granulation below 1 µm and specific surface area above 5 m2 / g, additives up to 5% by weight are added as sintering aids, selected from intermediate-phase aluminum oxides, except for the form ot, magnesium oxide, MgO, chromium oxide Cr ^ O , zirconium oxide ZrO? non-stabilized, yttrium oxide ^Υ 2θ3 ', titanium oxide TiOO, boron oxide B2O3, sintering of the platelets is carried out in an oxidizing atmosphere or humid hydrogen so as to obtain a relative sinter density close to 100% but with limited abrasive grain growth to a maximum of 2.5 pm measured by methods and then the sintered plates are subjected to a surface finishing treatment consisting in abrasive removal of the surface layer of the sinter with micro-cracks and possible chemical application of a nitride, carbide or carbon-oxy-nitride coating reducing the coefficient of friction with the treated material, according to patent No. 148 OBI, characterized by: that the addition of zirconium oxide was introduced into the oxide mixture in the form of an X-ray amorphous zirconium hydroxide gel Zr (OH) ₄ , and sintering of the platelets was carried out in an oxidizing atmosphere at a temperature of 1970 to 1270 K for 1 to 5 hours. * * *