SU799640A3 - Charge for producing ceramic material - Google Patents

Abstract

A mixture which exclusively consists of 98% by weight of nitrogen silicide, 1 to 60% by weight of aluminium nitride, 0.5 to 50% by weight of silica and 0.05 to 60% by weight of alumina or of 40-60% by weight of aluminium nitride, 15 to 45% by weight of silica and 0.05 to 50% by weight of alumina, is sintered at a temperature from 1200 DEG C to 2000 DEG C. Alternatively, the mixture contains at least 95% of the first-mentioned 4 substances and glass, melted at the said temperature, in the form of a borosilicate glass, iron silicate glass, manganese glass or lithium glass. This silica is present in a molar ratio of 1:2 with a part of the aluminium nitride, and the alumina is present in a molar ratio of 1:1 with the remainder of the aluminium nitride. In the absence of nitrogen silicide, the silicon/aluminium/nitrogen/oxygen atomic ratio is 6-z:z:8-z:z, with z > 4 and </= 5. The constituents of the mixture react with one another to form a ceramic material. This is intended for materials exposed to high temperatures.

Description

The invention relates to the preparation of a silicon nitride-based ceramic material. The manufacture of a ceramic material from a mixture containing more than 50% AbN, the rest is SiO, and 1.234 is known. However, in this case, it is not envisaged to obtain silicon oxynitride — an aluminum single-phase composition. A mixture for obtaining silicon oxynitride-aluminum is also known, containing 50-90% 81SY4 and 10-50% AKj material from which it is hot pressed at a temperature of 16501700s and a pressure of 150-250 kg / cm. However, this ratio in this two-component system does not result in a single-phase silicon oxynitride-aluminum. The purpose of the invention is to obtain a single-phase ceramic material in which the Si: AC:: N: O ratio corresponds to the formula (6-Z): Z: (8-Z): 2 where O Z 6 5, the goal is achieved due to that the charge for the manufacture of a kersey material, containing SijN4 and AygO, additionally contains SiO2 and Aby in the following ratio of components, wt.%: Ae2Oa 0.5-60 SiOi0.5-50 AgN1-60. 313 N4 Else, and the molar ratio of SiO and AZ O satisfies conditionally SiOg: XAy 1: 2 (K-X) AeN; Ag 03 1: 1, where K and X lie within the limits specified for the respective components. Example 1. A mixture of the following composition is prepared, weight,%: 75.34 silicon nitride with an average particle size of 3 μm and About 89%; 13.87 aluminum nitride having an average particle size of 11.5 microns; 0.89 alumina and 9.9 silica. Mixing and paramol of the components is carried out in a colloid mill in isopropyl alcohol to a particle size of less than 3 microns. The mixture is then sieved, sieved and hot pressed in a graphite mold, and, on all graphite surfaces, a layer of about 0.25 mm of boron nitride is pre-deposited. Temperature rise up to 1800 ° C and pressure up to 1.5 t / in 2 is carried out simultaneously. V,: rf «« |

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Claims (2)

 tebTo IO for 30 min, and kept under these conditions for 1 h. The resulting product, according to x-ray spectral analysis, consists of a practically single-phase material of composition S ±, t 7 where. The crystal structure of the material is (3-phase 81zY4 with changed parameters of the elementary cell a and with equal, 7.648 and 2.938, respectively. Example 2. From a mixture having a composition, wt.%: 41.34, 26.54 31 Hz, Si02 and 2.64, the material is obtained according to the method described in Example 1. A single-phase material is obtained, corresponding to the above formula, in which 2 3. The size a and from the unit cell is in this case, respectively, 7.70 and 2, 986. Example 3. From a mixture of the composition in wt.%: 12.50 S i 0.28, 36 AlzOz, 52.46 A 1N 7.03 Si3N4, the material is obtained by the described method, but at The hot pressing temperature is 1850 C. A virtually single phase material is obtained (95%), corresponding to the above formula, in which Z 4, .6. The optimum AS temperature for obtaining this material is 1500-1800 ° C, since it is in this interval that the reaction rate is high enough, and the weight loss of the ence is insignificant. Thus, the proposed composition of the charge makes it possible to obtain an almost single-phase product, silicon oxynitride, aluminum. Claims for the manufacture of a ceramic material based on silicon oxynitride-aluminum, comprising, in order to obtain a single-phase ceramic material in which the atomic ratio corresponds to the formula (6-Z): Z: (8-Z), where About Z 5, it additionally contains SiOg and AfiN in the following ratio of components, wt.%: Abz0.5-60. S1O20.5-50 AgN1-60 Si3N4 The rest is the molar ratio of SiO, and satisfies the condition SiO: xAgN 1: 2 (K-x) ABN: AgjO 1-1 where k and X lie within the limits specified for the respective components. Sources of information taken into account in the examination 1.Patent of Germany No. 1471035, cl. 80 b 8/183, 1970. 2. USSR author's certificate number 331047, cl. From 04 to 35/58, 1970.