SU952790A1 - Glass and method of making crystalline glass material therefrom - Google Patents

Abstract

Mica-contg. glass-ceramic materials which can be easily worked mechanically, contg. (in wt. %) :SiO2 35-55, Al2O3 15-35, FeO 5-15, K2O 5-15, F 1-15, Li2O 0-5, Fe2O3 0-5, TiO2 0-5, MnO 0-3, CaO 0-5, and Na2O 0-5. The material can be used as a substitute for grey cast iron. The fusion temp is relatively low (1250 degrees C) so that fluorine volatilisation loss is low. The temp of the formation of mica crystals is relatively low. The starting materials are fused together and cast into moulds at about 1250 degrees C, the cooling rate (down to 500 degrees C) does not exceed 500 degrees C/min. A one or two-stage thermal after treatment can be carried out at 450-900 degrees C.

Description

The invention relates to glass-ceramic materials that are characterized by good machinability on metalworking machines, for example, Yachka, drilling or milling using conventional tool materials, and which are suitable for use as materials substitutes.

Known glass for the manufacture of glass-ceramic material, including, wt.%: RO 3-30; Mg 1035; 0.5-26; .Si (J7 30-65 and F 3-15, while RO consists of SrO 3-30 and BaO 0-35.

The glass-ceramic material is obtained by melting the initial glass, having a composition within the specified interval, subsequent cooling and 1 controlled heat treatment in the temperature range of 700-1200 ° C to isolate the fluorinated mica phase l.

Closest to the invention in technical essence and the achieved result is glass for the manufacture of a glass-ceramic material, comprising, in wt.%: -SJOt.

25-60; 15-35 while RjO consists of, Hn15; Al.-jO 5-25 or 2-20, and R /) consists of NaeO 0-15; KjO 15; 0-15; CaO 0-20; MgO 4-25 and LijO 0-7, while MgO + LijO is 6-25 and F .4-25; Ti020-5.

The glass-ceramic material is obtained from the initial glass with a specified composition by controlled heat treatment in the temperature range of 750-1100 ° C according to a one- or two-stage scheme. Fluoroflogopite 2 crystals are obtained

ts

 However, production methods from natural materials are characterized by the need for controlled heat treatment of the original glass to control the crystallization of fluorinated glass.

20 mica crystals.

Claims (2)

To do this, it is necessary to cool the melt or the object formed from it at least to the interval of the glass transformation and then for one 25. or two-stage heat treatment is again heated to a temperature in the range of 800-1200s. The high temperatures at this stage of the process, depending on the composition, significantly increase the costs of obtaining the material. In addition, high melting points contribute to the evaporation of volatile fluorides. In addition, these glass-ceramic varieties processed on the walls have the disadvantage that they require large quantities of expensive raw materials containing aluminum magnesium and the corresponding phthooids. The aim of the invention is to simplify the process of making glass-ceramic material. This goal is achieved by the fact that glass for the manufacture of glass-ceramic material, including 5102 ,, ,, KjO, LigO, F Ti02, CaO, also contains FeO,, MnO at the following ratio of components, wt.%: SiOi 35-55 AlyO-15- 35 Niib 0.1-5. KdO5-1S LiP 0.1-5 TiOA 0.1-5 CaO 0.1-5 FeO5-15 0.1-5 MnO 0.1-1. The method of obtaining a glass-crystalline material involves cooking the glass and cooling it in the temperature range 1250-500 C at a rate of not more than 500 C / min and then arbitrarily to the lowest temperature. At the same time, it is preferable to cool in the temperature range of 1250-700C with a speed of lO-lOO C / min; The material obtained has hardly any characteristics: Thermal coefficient g-7 (90-120) expansion, hail Heat resistance, ® C 600 Mechanical workability with carbide tools Good Hydrolytic class 1 Acid resistance class11 Alkali resistance class 1IT Compressive strength J kg / cm Strength at bending , kg / cm tensile strength at tensile strength, kg / cm. Dielectric constant Breakdown strength, kV / .mm1-2. Temperature, from 1250-13 Example 1. Glass containing weight,%: SJOj 46; 24; FeO 11.5; Kj.O 10.5; F 5.0; NajO 0.5; MnO 0.8; 0.5; CaO 0,2; TiO, 0.7 and, 0.3, is boiled in a crucible of sintered corundum for 1 hour at 1300 s, poured into a metal mold and cooled at a cooling rate of SO / C to 650 C, and then to room temperature with a speed Zs / min The obtained glass ceramics contains 40 vol.% Zinwaldite, is distinguished by very good machinability on machines, very good hydrolytic resistance and thermal coefficient of linear expansion 107107 s. Example 2. Glass containing, wt%: SiOj, 39; ,, thirty; FeO 8.5; KjO 10.0; F 9.0; NajO 0.8; MnO 0.5; 0.6; CaO 0.1; Ti02l, 0 and 0.5, is varied by the method described in Example 1, cooled in metallic form at a cooling rate of 300 ° C / min to, and then to room temperature at a rate of 3 ° C / min. The resulting glass ceramics contains 50 vol% zinwaldite and is very well machinable on machine tools. Example 3. Glass containing, wt.%: SiOj 35; thirty; FeO 12; five; F 3; 2; Re, TiO.l; MnO 1; CaO 2 and NajO 5, is heated and cooled in metallic form at a cooling rate of 40 C / min to 800 ° C and then to room temperature at a speed of 5 sec / min. Glass ceramics contains 40 vol% zinwaldite and is characterized by very good machinability. Example 4. Glass containing, wt.%: SiOj 50; FeO 15; KjO 9; F 4; 0.7; TiOjO; MnO 0.1; CaO is 0.1 and 1.0, is cooked and cooled in metallic form at a cooling rate of 15 C / min to 750 ° C, and then to room temperature at a rate of 5 C / min. The resulting glass ceramics contains 50 vol% zinwaldite and has very good machinability. Other examples are given in the table. Thus, according to the invention, compositions have been developed which, as compared with the prior art, have low melting points and, therefore, little evaporation of fluorides during cooking and which can be obtained by simple technology during the cooling process. Claim 1. Glass for the manufacture of glass of crystalline material, including SiO ,,, NajO,,, F TiO, SGaO, characterized in that, in order to simplify the manufacturing process, it additionally contains FeO, FejOj, MnO with the following ratio of components , weight.%; 2. A method for producing a glass-ceramic material, including the melting of glass and its cooling, characterized in that the cooling in the temperature range of 1250-500s is carried out at a speed of not more than 500 C / min and then arbitrarily to room temperature. 3. A method according to claim 2, characterized in that the cooling in the temperature range 1250-700s is carried out at a rate of lO-lOOc / min. Sources of information taken into account in the examination 1. For the FRG 2224990,, cl. 32 3/32, published. 1972. 2. For Germany 2133652, 1kl. 32 3/32, published. 19.72