CS210047B1 - Machinable glass crystallic substance containing the the mica - Google Patents

Abstract

Machinable mica-contg. glass ceramic, (I) having graded workability and strength contains by wt. 15-35% Al2O3, 5-15% K2O, 1-15% F, 0-5% Li2O, 0-5% Fe2O3, 0-5% TiO2, 0-3% MnO, 0-5% CaO and in addn. 35-65% SiO2, 5-22% FeO, 0-10% Na2O, where =15% FeO may be replaced by an equiv. quantity of MgO, and K2O + Na2O =15%. (I) can be used as metal substitutes. The FeO replacement by MgO improves machinability and reduces crystallisation-tendency of FeO-contg. melts. Slow heating rates favour strength, whereas quick heating rates favour machinability. (I) are chemically stable, have higher bending strength than glass and a low heat-expansion coefft.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a machine-machined glassy crystalline mass containing mica with graduated machinability and strength. The choice of the composition of the glass panes for these vitreous crystalline masses enables that the strength and machinability of the vitreous crystalline masses can be adjusted to the desired values continuously over a wide range by the unequal additional heat treatment.

It is known that the basic glasses for the production of glass-machinable crystalline masses have compositions based on solids.

R2O-MgO-R ₂ O 3 SiO ₇ -F RO-MgO-A1 ₂ 0 03 Si ₂ ~ FR ₂ O-MgO-Si0 ₂ -F wherein

R ₂ 0 denotes N and ₂ 0, К O, R b ₂ O or C with 2 O RO denotes SrO or BaO 1 R ₂ 0 denotes Α1 ₂ θ3 or B ₂ O3

The heat treatment of glass samples of this composition eliminates the crystalline phase of fluorinated mica, which has a similar composition to the phlogopites occurring in nature. The general formula of these fluorine mica is ^x 0.5-I-2 ~ 3 ^Z 4 ° 10 ^F 2>

wherein X, Y and Σ '. they are cations, her ch- Lomrometers can have these values X = 1, 0 to 1.6. 10 ~ ¹⁰ rn, Y « 0.6 to 0.9. 10 “10 m a 2 - 0.3 to 0.5. 10 ^1ΰ m.

Glass batches of this composition must be melted and processed at high temperatures, and the production of the glassy crystalline mass therefrom can only be very costly by reheating. Glassy crystalline masses have therefore been developed based on glass batches having a composition such that their melting and processing takes place at lower temperatures and the costly temporalization of the glassy crystalline mass required therefrom is not required. However, a disadvantage of these glassy crystalline compositions is that their properties cannot be scaled over this wide range, such as the properties of metallic materials. The prior art glassy crystalline masses do not sufficiently meet this requirement.

It is already known that the machinability of vitreous crystalline masses can be improved by increasing the boron oxide content of the base glass. On the contrary, it is known that the machinability of the glassy crystalline masses deteriorates by increasing the alkali metal oxide content of the base glass and that other glassy material's properties can be altered by other additives.

It is further known that machine machinability is causally related to the deposition of fluorine mica crystals, which occurs, in particular, at temperatures between 1050 ° C and 1200 ° C, so that in the production of glassy crystalline masses it is necessary suction at these temperatures.

All of these known designs pursue the objective of producing vitreous crystalline masses that are as machine-friendly as possible. However, no method has been developed which allows the production of many variants of glassy crystalline materials with different mechanical properties. The hitherto proposed possibilities of modifying certain properties of glassy crystalline materials by varying the composition of the base glasses used in their manufacture is not sufficient to develop glassy crystalline materials fully replacing the various metals. This requires glassy crystalline materials whose strength and machinability values are varied within wide limits.

The technical problem solved by the present invention is therefore to develop a glassy crystalline mass with graded strength and machinability values while improving their machinability by varying their composition.

According to the present invention, the aforementioned disadvantages are overcome by manufacturing machinable and mica-containing glassy crystalline materials with graduated machinability and strength values. The substance of the invention consists in that the mass consists of alumina with a mass concentration in the range of 10 to 25%, potassium oxide in a mass concentration of between 5 and 17%, fluorine with a mass concentration of between 1 and 15% and magnesium oxide; or a ferrous oxide in a weight concentration in the range of 5 to 22 2, wherein the maximum weight concentration of magnesium oxide is 15 Z. Together with these components, the mass comprises silica in a weight concentration in the range of 35 to 65 Another feature of the present invention is material preferably contains carbon, sodium and / or carbon potassium in a concentration of more than 1 5 7 _0, the content of sodium oxide is in the range trace to 10 Z and optionally containing oxide of lithium in a concentration ranging from traces up to 5%, and / or titanium dioxide in weight k a concentration in the ⁷ trace range to 2 Z and a manganese oxide concentration in the weight range of up to 3% and / or ferric oxide in a weight concentration in the range of track to 9 °.

It has been found that replacing up to 15% of iron oxide in the above mixture with an equivalent amount of magnesium oxide improves machine machinability and gives greater flexibility to change the machinability and strength values of the glassy crystalline mass produced. It is also possible, while maintaining the advantageous properties of the glassy crystalline mass, to replace up to 15% of alumina in the base glass with a cheaper component of iron oxide. The good chemical and physical properties of the vitreous crystalline mass are not substantially altered thereby promoting the crystalline phase deposition of the layered silicates, which condition the machinability, so that by sufficiently slow cooling from the melt a layered crystalline glass structure advantageous for the rob iteInost. In addition, advantageous melting and processing temperatures for these glasses can be maintained.

The addition of magnesium oxide reduces the crystallisation tendency of the iron oxide-containing melts, thereby allowing the crystallographic process to be controlled. Effect of magnesium oxide in the system

R ₂ 0- / MgO Fe0 // Al ₂ 0 _3, Fe ₂ O ₃ / F--SiO9 consists, first, in the formation of finely laminated mutually crosslinked biotite formula / K, Na // MgFe / ₃ / SiAlFe / ₄ O ₁ F ₂ wherein the Mg ²⁺ cations having the same radius as the Fe ²⁺ cations occupy the position of these cations in the octahedral gaps between the tetrahedral layers. In addition, the addition of magnesium oxide increases the viscosity of the base glasses. The increase in the activation energy for crystal exclusion thereby avoids the very rapid talization typical of glazing containing gaseous oxide, so that the crystallization process is more manageable.

For this treatment, the magnesium oxide forming process involves glassy-crystalline compositions according to the invention, which is carried out by controlled cooling of the glass melt vyykysstaisováni, wherein the melt is maintained for 0.5 to 3 hours in te Lot ^p between ^1,050 and ^at 850 C ^d .

It is known that the machinability and strength of the glassy crystalline masses are influenced by the size of the mica crystals, the ratio of their diameter to the thickness on which the degree of crosslinking and the ratio of the mica crystals to the mass of the remaining glass structure depend. The vitreous crystalline structure, and thus its brightness and strength, can therefore be altered by varying the cooling process within the prescribed limits.

The course of cooling depends on the desired mechanical property. The course depends, among other things, on the FeO: MgO ratio in the glass, but can also be influenced by the addition of segregating components, such as, for example, lithium oxide. By adding up to 5 · Umotnotsi of l-aine oxide to. The base glass can be achieved by creating a desired glassy crystalline mass structure.

One preferred method of making the machine-machined glassy crystalline masses of the present invention using crystalline glass capable of being cooled to at least the transformation temperature region comprises one-stage or two-stage controlled heat treatment. .

The scaling of the values of the glassy crystalline materials produced is carried out by subjecting the thermally crystallizable glass body which has been cooled to at least the basic transformation temperature to undergo, optionally, cells with a stepwise or two step controlled heat treatment for crystallization.

In a single-stage heat treatment, the body is heated from the point of transformation to a heat ^t of Шл from 0.5 to 10 ° C / min. ^{950 F} and ¹⁰³⁰ ° C, ^{the hook} of something at this temperature for 1-8 hours and then cooled to mísSnotSí. In particular, it has been found that at low heating rates, especially the mechanical strength of the glassy crystalline hmooy improves, while at higher heating speeds of the base glasses, the machine perimetry is improved so that the desired gradation of properties can be achieved by selecting certain heating rates.

By utilizing a two-stage controlled thermal treatment of the glass capable of thermal crystallization and having been cooled to at least the basic transformation temperature, the glass is heated by controlled heating to an ambient temperature. ⁷⁰⁰ and ^{Z 920} ° C, ^p Oneco ^hook at ^this temperature for 1-8 Uodde then řízzenym heating further heated to a temperature in ob basti 950-1 030 ° C, maintained at this temperature for 1-8 hours and then cooled to room temperature. In this method of controlled two-stage heat treatment, the desired hygroscopic grading can also be achieved by suitable selection of heating temperatures and holding times. In particular, the mechanical strength of the glassy crystalline Umooy has been found to be increased by prolonging the temperature holding time in the region of 700 to 920 ° C.

By using both single-stage and two-stage controlled heat treatment, a series of vitreous crystalline Umot with graded mechanical strength and oboobieZooosi can be produced, with an increase in mechanical strength always associated with a deterioration in machine obboobieleoosi.

The production method by which a machine-crystalline vitreous crystalline mass with a wide range of graded mechanical strength and obsolete values is obtained is based on the discovery that the formation of mica gypsum is not bound to the excretion of MgF? The biotite is not an advantage for the preferential secretion of selala as a nucleation. This discovery was unequivocally confirmed by electoon micboscoopy and X-ray examination. Of course, the deposition of silane is bound to the presence of MgO in the glass according to the invention, and the presence of ferrous oxide in the glass is not necessary for such deposition, so that the deposition proceeds even under complete indirect immunity of the ferrous oxide.

U s ke lnn. The crystalline crystals of the compositions according to the invention, which contain magnesium oxides, have been found, particularly in the case of a low thermal spraying performed at a low heating temperature of 0.5 to 3 ° C / min, to increase the content of the heating with a faster heating. The same was found to increase the temperature holding time in Zbašt from 700 to 920 ° C during the two-stage heat treatment. Since in both cases the mechanical strength of the glassy crystalline masses increases, it has to be assumed that the deposition of sejlaite is directly related to the desired graduation of this moisture content. Furthermore, it has been found that sejlaite has a direct effect not only on the technical foaming, but also on the crystallinity of the vitreous crystalline particles.⁺ and^F”^totzré nezb^ytné^pro you^tvo^Řof mica and botite crystals. In addition, by decreasing the fluorine content of the residual glass phase, the viscosity and tm also increase the activation energy for the elimination of further cobasic phases, in this case for the elimination of fluorine mica. These factors result in a decrease in the growth of mica crystals and the deposition of layer-bonded silicates in the deposition of selaite, the smaller the crystals are the smaller the concentration of selaite. Reducing the size of these crystals leads to an increase in mechanical strength at the cost of deteriorating the machine by s, but this property is not completely lost. Thus, it is possible by eliminating quite certain connec- tions of the silane to adjust the strength and machinability of the glassy crystalline masses to the desired value, continuously and in wide measure.

In this way, each intermediate stage between a vitreous crystalline heater having excellent < Desc / Clms Page number 2 &gt; but mechanical strength of only conventional technical glasses, and a vitreous crystalline Umooa having a high strength, e.g. only special tools. Thereby lzz obtain a wide selection of glassy crystalline masses with graded properties. The produced crystalline glass crystalline masses of the composition according to the invention have a good chemical stability and have a considerably higher flexural strength and a relatively small coefficient of thermal expansion compared to ordinary glass. The advantage to undergo ^o w ⁿ his condition ^^ ^j rivets from ^{Io, F} e c ^{u jnji} meehanic ^Ké vlhatiot ^network, especially ^a y ^am echani ^ck .ápevnost the machine for milling mow, are šibokýcU odstupňovaaelné limits, thereby significantly increasing these pouUžtelitsí glass - crystalline masses as a substitute material for the metal city,.

Examples of the invention are illustrated in the accompanying tables. Tables 1 and 2 show the chemical composition of some selected base glasses in the table.

from which the glassy crystalline compositions according to the invention can be produced with graduated machinability and mechanical strength. The individual components were introduced into the glass batch in the form of oxides or carbonates, with the exception of fluorine which was introduced as aluminum fluoride or magnesium fluoride and with the exception of iron oxide which was introduced in the form of ferrous oxalate. It should be borne in mind that, when iron is introduced into the feed, a certain equilibrium ratio of iron (III) oxide usually stabilizes, but that under the melting conditions chosen according to the invention this equilibrium has not been reached, so that the ratio of iron (III) to the original degree of oxidation of the introduced iron. This was demonstrated by the analysis of glass.

Tables 3 and 4 show how far the properties of the glassy crystalline compositions of the invention can be modified by varying the additional heat treatment or by changing the cooling conditions.

Bending strength was measured on 25 carefully cooled rods with a diameter of 3 to 5 mm and a length of 60 mm. As in the glass test methods, uniform surface damage was found by treating the test rods in a tumbling drum of silicon carbide with a grain size of 0.06 to 0.10 mm for 30 minutes at 50 rpm. The bars were then broken on a three-point washer with a cutting edge distance of 50 mm. The load time gradient was constantly 2 Ns’1. The flexural strength thus determined was between 120 and 280 MPa. For comparison, the fracture strength of the Rasotherm glass rods was measured under the same conditions, and the measured value was 80 MPa.

The chemical resistance, expressed by inclusion in hydrolytic and leaching classes, was determined according to the standards applicable to technical glass tests. These measurements showed that the glassy crystalline compositions of the present invention had weight losses above 250 mg.dm &lt; -1 _{&gt; and} mostly belonged to leach class 2, while the acid consumption was 0.1 ml, g-1 using 0.01 N acid solution. hydrochloric acid, so they mostly belong to hydrolytic class 1. Thus they have good to very good chemical resistance.

The linear coefficient of thermal expansion was measured by an optical dilatometer, and for the glassy crystalline masses of the present invention, in the temperature range from 200 [deg.] C. to 500 [deg.] C., values between 50.10 &lt; -1 &gt; K “1.

Table 1

Composition of basic glasses

Glass number

Folder 1 2 3 4 5 6 7 8 SiO2 55.9 56.0 56.3 50.4 49.7 54.6 56.0 49.0 А1 ₂ 0з 15.6 15.1 10.3 16.1 1 1, 2 12.0 14.3 17.1 MgO 12.2 12.5 10.8 - 10.8 - 11.5 - FeO - 3.0 0.6 14.1 2,0 16.3 0.8 15.8 FeaOq 2.3 - 5.0 5.2 7.6 3.0 6, 0 5.0 I ^ O 17.0 6.0 6.7 8.0 12.2 8.0 6.8 4.1 Na _o O - 1> 0 - - - - - 4.2 F ² 7.0 5.2 10.3 5.2 6.5 6.1 4.6 4.8 Li ₂ 0 - - - 1.0 - - - - MnO - - - - - - - - CaO - - Explanation: Numbers in table indicates weight concentration / in Z / 8folders, referred to in p rvním

table column

Table 2

Composition of base glasses / continued /

Glass number

Component 9 10 11 12 13 14 15 Dec 16 17 With iO2 AI2O3 MgO 53.6 61.4 54.6 38.2 40.1 53.0 58.1 53.0 57.8 14.0 5.5 11.8 17.6 10.0 24.8 22.0 16.8 8.2 1 1, 5 12.6 10.1 1 1, 8 18.6 9.3 FeO 11.1 7.5 3.0 16.3 1 7, 0 8.4 - 1, 5 1, 1 0.2 6.6 Fe 2О3 and ₂ ο 2.5 6.5 0.5 4,5 0.8 6.6 2.2 2,0 1, 2 8.7 1.5 6, 0 2.8 7.4 8.6 6.8 At ₂ 0 0.8 2.1 - 8.0 0.5 - - - - F 6.0 5, 0 6.6 6.5 5.5 6.1 7.6 8.2 6.4 L1O2 - 4.2 0.8 2,0 2.1 0.8 - - MnO - - - - CaO - 1.0 - - 1.0 - - tío ₂ - 1.0 - - 1.1 Explanation: Numbers in table indicates weight concentration / v 7 <J of the ingredients listed in first

table column

Table 3

Properties of glassy ^to crystalline materials in dependence on heat treatment

Glass number

1

4

7

7

7

Thermal AND treatment ObbobiteLeott D Strength E Extensibility F (B) C 770 AT 3.0 3 26.8 67.1 1070 AT 3.5 1070 770 AT AT 3.5 3.0 * 2 3 18.2 22.2 47.4 62.1 1070 AT 3.5 770 AT 3.0 2 19.8 53, 5 1070 AT 3.5 1 100 0 1 15.4 70.2 1 100 0 - 1 14.7 48.7 1 100 0 - 1 17.6 63.7 770 at 3.0 2 19.7 67.9 1070 at 3.5 1 100 at 2,0 2 21,1 ‘ 65.4 1100 0 - 1 49.4 970 at 3.0 2 1100 at 2,0 2 850 at 2,0 4 970 at 3.0 970 X 4 24.8 970 at 3.0

Explanatory notes to Table 3

Column A: Temperature in ° C.

Column B: Tags have the following meanings

Maintained at the temperature in column A for the period indicated in column C 0-cooled from the temperature in column A

X-cooled to the temperature indicated in column A at a rate of 1 ° C. min “1

Column C: The time to maintain the temperature given in column A in hours

Column. D: Scale graded machinability

- vm ^ lm. dolbá

- dolbá

- additional

- needoSecret / nbobrbbitelbott /

Column E: ultimate fracture strength vMPa. 10 "^'S l ^oupec F ^{^} uuinétel temperature roztahoeH in ^{K1. 10} * ⁷

Table 4

Chemical properties of glassy crystalline masses

Number Losses Class Krys Italy glass G H K L 1 26 7 1 1 fb / se 3 225 1 2 fb 5 237 1 2 fb / se 7 152 1 2 fb / se 9 420 2 2 fb 1 1 330 1 2 fb 14 316 1 2 fb 1 5 238 1 2 fb 16 276 1 2 fb 1 7 310 1 2 fb

to Table 4:

Column G explains:

Column H: Column K: Column L:

Extraction loss, in mg / dm ‘^ ο ^ υ ^ Μ class Extraction class KrysSalic phase, expressed by fb« se = seHa ^ t

Claims (3)

SUBJECT A machine-machined glassy crystalline mica-containing mass is characterized in that it consists of silica in a 35-65% thick, conc. with a concentration of 1 to 15 Z, potassium oxide in the castle with a concentration of 5 to 17 Z, and that the oxide and / or magnesium carbonate OF THE INVENTION. π 5 to 22 Z, where the maximum concentration of magnesium oxide is 15 Z. 2. The machine-crystalline vitreous crystal of mica according to claim 1, characterized in that it contains potassium oxide and / or sodium oxide in the terminal end (1 to a maximum of 15%), the sodium oxide content of which is Track range up to 10 Z. 3. A mica-containing machinable vitreous crystalline mass according to claim 1 or 2, characterized in that it contains lithium oxide in a weight concentration in the range of traces up to 5 Z and / or titanium dioxide in a weight concentration in the range 9 to 2 Z and manganese dioxide. a weight concentration in the range of trace to 3 Z and / or a ferric oxide in a weight concentration in the range of trace to 9 Z