DE3212612A1 - Chemically curable watch glass of high Knoop hardness - Google Patents

Chemically curable watch glass of high Knoop hardness

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Publication number
DE3212612A1
DE3212612A1 DE19823212612 DE3212612A DE3212612A1 DE 3212612 A1 DE3212612 A1 DE 3212612A1 DE 19823212612 DE19823212612 DE 19823212612 DE 3212612 A DE3212612 A DE 3212612A DE 3212612 A1 DE3212612 A1 DE 3212612A1
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Germany
Prior art keywords
glass
oxides
knoop hardness
weight
glasses
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Granted
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DE19823212612
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German (de)
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DE3212612C2 (en
Inventor
Georg Dipl.-Ing. Dr. 6500 Mainz Gliemeroth
Lothar 6227 Oestrich-Winkel Meckel
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Schott AG
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Schott Glaswerke AG
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Priority to DE3212612A priority Critical patent/DE3212612C2/en
Priority to CH122483A priority patent/CH662918GA3/de
Priority to JP58058839A priority patent/JPS58185451A/en
Publication of DE3212612A1 publication Critical patent/DE3212612A1/en
Application granted granted Critical
Publication of DE3212612C2 publication Critical patent/DE3212612C2/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
    • C03C21/001—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions
    • C03C21/002—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions to perform ion-exchange between alkali ions
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/095—Glass compositions containing silica with 40% to 90% silica, by weight containing rare earths
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C03C4/02—Compositions for glass with special properties for coloured glass

Abstract

A watch glass which, due to chemical curing by means of ion exchange, has high flexural and good scratch resistance comprises (in % by weight) Si 55-68, Al2O3 11-21, B2O3 0-6, La2O3 0-2, TiO2 0-1, NaO 9-15, K2O 1-8, MgO 0.5-4, CaO 0-2 and other oxides 0-7, including pigment oxides, for example CoO, in order to achieve a blue colouration.

Description

Beschreibungdescription

Uhren und ähnliche Geräte haben Abdeckscheiben, die je nach Qualität des Gerätes aus durchsichtigem Kunststoff oder Glas hergestellt sind.Watches and similar devices have cover plates that vary depending on the quality of the device are made of clear plastic or glass.

Im folgenden Text wird der Einfachheit halber nur von Abdeckscheiben für Uhren gesprochen (Uhrgläser).In the following text, for the sake of simplicity, only covers are used spoken for clocks (watch glasses).

Die Kratzempfindlichkeit der Kunststoffe, die bedingt ist durch ihre geringe Härte, stellt einen schwerwiegenden Nachteil dieses Materials dar. Deshalb ist man frühzeitig wieder zurückgegangen auf sogenannte Mineral gläser, die im Prinzip nichts anderes sind als geschliffene, polierte Schlagglasprodukte, die heute meist aus Floatglas, bei höheren Ansprüchen an die Transmission auch aus B 270 oder D263 (DESAG,Grünenplan) hergestellt werden.The scratch sensitivity of plastics, which is due to their low hardness, is a serious disadvantage of this material. Therefore One went back to so-called mineral glasses at an early stage, which in principle are nothing more than cut, polished blown glass products, which are mostly today made of float glass, with higher demands on the transmission also made of B 270 or D263 (DESAG, Grünenplan).

Für besonders teure Uhren wird auch Saphir verwendet, jedoch ist der Preis für dieses Material um ein vielfaches höher als der des obengenannten Mineral glases, und dieses wiederum ist teurer als der Kunststoff.Sapphire is also used for particularly expensive watches, but it is Price for this material many times higher than that of the above mineral glass, and this in turn is more expensive than plastic.

Es wurde auch bereits versucht, durch chemische Härtung mittels Ionenaustausch an Mineral gläsern Materialien zu schaffen, die zumindest in ihrer Biegezugfestigkeit verbessert sind. Hier ist die DE-AS 26 14 566 zu erwähnen, welche die Verwendung von ionenausgetauschten verfestigten Gläsern beschreibt. Daneben sind die JP-OS.en 79 15 2013 und 79 15 2014 bekannt, die ebenfalls Gläser für Abdeckscheiben von Uhren empfehlen, welche durch Ionenaustausch verfestigt wurden. Zum weiteren Stand der Technik gehört auch die JP-OS 81 59 642. Insbesondere in dieser Anmeldung wird die Erzeugung einer Spannungsschicht durch Ionenaustausch hervorgehoben, wobei die Dicke der Druckspannungszone 15 /um beträgt und die Druckspannung 60 kg mm² erreicht.Attempts have also been made by chemical hardening by means of ion exchange to create mineral glass materials that at least in terms of their flexural strength are improved. Here the DE-AS 26 14 566 should be mentioned, which the use of ion-exchanged solidified glasses. In addition, the JP-OS.en 79 15 2013 and 79 15 2014 known, which are also glasses for cover plates of clocks recommend that have been solidified by ion exchange. To the further status of the Technology also belongs to JP-OS 81 59 642. In this application in particular, the Creation of a stress layer through ion exchange, the thickness being highlighted the compressive stress zone is 15 µm and the compressive stress reaches 60 kg mm².

Die als Mineral gläser bezeichneten Glaszusammensetzungen besitzen aufgrund ihrer sehr verschiedenen Zusammensetzung unterschiedliche Festigkeiten und Härten. Der Zusammenhang zwischen Glaszusammensetzung und der Möglichkeit der chemischen Härtung durch Ionenaustausch einerseits und der Härte der Gläser andererseits wird ausführlich behandelt in der Arbeit von Gliemeroth, "Untersuchungen zur Wirkung von Schlägen auf Glas mit und ohne Vorspannung" (Glastechnische Berichte 47 (1974) 97-106). Es ist besonders hervorzuheben, daß eine Steigerung der Biegezugfestigkeit durch Ionenaustausch unabhängig von der verschiedenen Dicke der Austauschzone keinen oder nur geringen Einfluß auf die Härte besitzt. Tabelle 3 dieser Veröffentlichung zeigt die Eigenschaften aus gewählter Gläser mit und ohne chemische Vorspannung (Härtung durch Ionenaustausch), insbesondere die Veränderung der Knoop-Härte vor und.nach dem Ionenaustausch. Die dort verzeichnete Glastype B 270 ist eines der heute am häufigsten verwendeten Mineral gläser in der Uhrglasindustrie.The glass compositions referred to as mineral glasses have different strengths due to their very different composition and hardening. The relationship between glass composition and the possibility of chemical hardening through ion exchange on the one hand and the hardness of the glasses on the other is dealt with in detail in the work of Gliemeroth, "Investigations on Effect of impacts on glass with and without pre-tensioning "(Glastechnischeberichte 47 (1974) 97-106). It should be particularly emphasized that an increase in the flexural strength due to ion exchange, regardless of the different thicknesses of the exchange zone, none or has little effect on hardness. Table 3 of this publication shows the properties of selected glasses with and without chemical tempering (Hardening through ion exchange), especially the change in Knoop hardness and.after the ion exchange. The glass type B 270 listed there is one of the Mineral glasses most commonly used today in the watch glass industry.

Ziel der vorliegenden Erfindung ist ein Glas, das sich durch hohe Biegezugfestigkeit und gute Resistenz gegen Kratzer auszeichnet. Die.Biegezugfestigkeit soll durch chemische Härtung mittels Ionenaustausch erzielbar sein.The aim of the present invention is a glass that is characterized by high Flexural strength and good resistance to scratches. The bending tensile strength should be achievable through chemical hardening by means of ion exchange.

Das unausgetauschte Glas soll bereits eine möglichst hohe Resistenz gegen Kratzer, repräsentiert durch eine Knoop-Härte von 500 kp mm 2 besitzen, die durch den Ionenaustausch auf > 600 kp mm steigerbar sein soll.The non-exchanged glass should already have the highest possible resistance against scratches, represented by a Knoop hardness of 500 kp mm 2, which should be able to be increased to> 600 kp mm through the ion exchange.

Weiterhin soll das neue Glas solche Kristallisations- und Viskositätseigenschaften haben, daß es als Dünnglas zwischen 0,5 und 1,5 mm so zu ziehen ist, daß seine Oberflächenqualität die direkte Verwendung ohne Schleifen und Polieren ermöglicht, so daß also aus dem Dünnglas nur die Uhrgläser herausgeschnitten, chemisch gehärtet und in die Uhren eingebaut zu werden brauchen.Furthermore, the new glass should have such crystallization and viscosity properties have that it is to be drawn as thin glass between 0.5 and 1.5 mm so that its surface quality allows direct use without grinding and polishing, so that from the Thin glass just cut out the watch glasses, chemically hardened and put them into the watches need to be built in.

Außerdem soll das neue Glas eine gute chemische Beständigkeit aufweisen, und schließlich soll die Möglichkeit-gegeben sein, das Glas gezielt so einzufärben, daß es bestimmten natürlichen Saphir-Qualitäten dank eines leichten Blaustichs ähnelt.In addition, the new glass should have good chemical resistance, and finally the possibility should be given to color the glass in such a way that that it resembles certain natural sapphire qualities thanks to a slight blue cast.

Es wurde gefunden, daß sich bestimmte Gläser innerhalb eines eng begrenzten Zusammensetzungsbereichs durch Ionenaustausch mit gutem Ergebnis im Hinblick auf erreichbare.Schichtdicke und Spannung härten lassen, und daß sich diese Zusammensetzungen bei relativ hoher Ausgangs-Knoop-Härte von mindestens 500.kp mm-2 zudem auf Knoop-Härten von über 600 kp mm durch diesen Ionenaustausch verbessern lassen. Diese Glaszusammensetzungen sind in den Patentansprüchen angegeben.It has been found that certain glasses are within a narrow range Composition range by ion exchange with good result in terms of Achievable layer thickness and tension can be cured, and that these compositions with a relatively high initial Knoop hardness of at least 500.kp mm-2, also to Knoop hardness of over 600 kp mm can be improved by this ion exchange. These glass compositions are specified in the claims.

Diese Gläser zeigen darüber hinaus Kristallisations- und Viskositätseigenschaften, die eine Massenfertigung durch Ziehen in Dicken von 0,5 bis 1,5 mm problemlos gestatten. Die Rohstoffkosten sind erheblich niedriger als die der Lanthan-Schwerflint-, Lanthan-Flint- und Lanthan-Krongläser.These glasses also show crystallization and viscosity properties, which allow mass production by drawing in thicknesses of 0.5 to 1.5 mm without any problems. The raw material costs are considerably lower than those of the lanthanum heavy flint, lanthanum flint and lanthanum crown glasses.

Die Qualität der Oberfläche der erfindungsgemäßeh Gläser nach dem Ziehen ist so, daß von einem nachträglichen Schleifen und Polieren abgesehen werden kann.The quality of the surface of the glasses according to the invention after Drawing is such that subsequent grinding and polishing are not necessary can.

Durch einen Ionenaustausch in einem kaliumionenhaltigen Salzbad bei Teniperaturen über 3600 C werden Austauschzonen von mehr als 80 /um Dicke erzeugt, in denen Druckspannungen von über 5000 nm/cm herrschen.With an ion exchange in a salt bath containing potassium ions Temperatures above 3600 C create exchange zones with a thickness of more than 80 μm, in which compressive stresses of over 5000 nm / cm prevail.

Die Knoop-Härte ist abhängig von der Belastung. In Anspruch 1 wird von 200 g Last gesprochen. Ein Vergleich mit anderen Belastungen klärt den Zusammenhang an ein und demselben erfindungsgemäßen Glas: Last 50 g (0,49 iNy HK 770 kp mm Last 200 g (1,96 N) HK 630 kp mm 2 Die Zusammensetzung der erfindungsgemäßen Gläser in Gewichtsprozent der Synthese ist also wie folgt: SiO2 55 bis 68 B203 0 bis 6 £ SiO2 + B203 -+ P205 + Ge02 55 bis 68 Al203 11 bis 21 La203 0 bis 2 TiO2 0 bis 1 # Al2O3 + La2O3 + TiO2 + ZrO2+ Nb2O5 11 bis 24 Na20 9 bis 15 K20 1 bis 8 £ Alkalioxide 10 bis 18 MgO 0,5 bis 4 CaO 0 bis 2 £ MgO + CaO + BaO + SrO + ZnO 0,5 bis 6 Sonstige Oxide 0 bis 7 Für La203 können auch andere Seltenerdoxide eingesetzt werden.The Knoop hardness depends on the load. In claim 1 is spoken of 200 g load. A comparison with other loads clarifies the connection on one and the same glass according to the invention: load 50 g (0.49 iNy HK 770 kp mm load 200 g (1.96 N) HK 630 kp mm 2 The composition of the invention Glasses in percent by weight of the synthesis is therefore as follows: SiO2 55 to 68 B203 0 up to 6 £ SiO2 + B203 - + P205 + Ge02 55 to 68 Al203 11 to 21 La203 0 to 2 TiO2 0 to 1 # Al2O3 + La2O3 + TiO2 + ZrO2 + Nb2O5 11 to 24 Na20 9 to 15 K20 1 to 8 £ alkali oxides 10 to 18 MgO 0.5 to 4 CaO 0 to 2 £ MgO + CaO + BaO + SrO + ZnO 0.5 to 6 Other oxides 0 to 7 Other rare earth oxides can also be used for La203 will.

Der Zusammensetzung können geringe Mengen an färbenden Oxiden zur Erzeugung farbiger Uhrgläser beigefügt werden; eine Menge von 0,001 Gew.-0 Kobaltoxid erzeugt z.B. einen blauen Farbstich, wie er häufig bei bestimmten Saphirqualitäten beobachtet wird.Small amounts of coloring oxides can be added to the composition Production of colored watch glasses are attached; an amount of 0.001% by weight of cobalt oxide e.g. creates a blue color cast, as is often the case with certain qualities of sapphire is observed.

Der Einfluß der Glaszusammensetzung auf die wichtigsten Eigenschaften läßt sich gut an dem nachstehenden Vergleich erkennen; die Gläser 5999 und 6023 sind Erfindungsbeispiele, die Gläser 6105 und 0038 sind Vergleichsbeispiele: 5999 6023 6105 0038 SiO2 60,00 6D,00 60,00 60,00 B2O3 - 5,00 5,00 7,00 Al203 20,00 15,00 10,00 13,00 La203 1,00 1,00 1,00 1,00 Na20 14,00 14,00 14,00 14,00 K20 3,00 3,00 3,00 3,00 Tip2 0,50 0,50 0,50 0,50 MgO 2,00 -2,00 7,00 2,00 A5203 0,50 050 0,50 0,50 CO2O3 0,001 0,001 0,001 0,001 Tg (°C) 628 565 564 557 Ew (°C) 840 780 740 740 VA (°C) 1267 1135 1060 1065 Härte -2 ohne IA kp mm 520 550 520 520 mit IA kp mm-2 630 660 530 530 Kristallisation 60 min TB keine keine keine keine Schichtdicke µm nach IA / 120 110 105 85 Spannung nm/cm 7000 7300 8100 4400 nach IA Man erkennt daran sehr klar, daß Veränderungen der Zusammensetzung zur Viskositätserniedrigung bei gleichbleibender Vermeidung der Kristallisation sofort die zusätzliche Steigerung der Knoop-Härte durch den Ionenaustausch (IA) zunichte werden lassen.The influence of the glass composition on the most important properties can be seen well by the comparison below; the glasses 5999 and 6023 are examples of the invention, glasses 6105 and 0038 are comparative examples: 5999 6023 6105 0038 SiO2 60.00 6D, 00 60.00 60.00 B2O3 - 5.00 5.00 7.00 Al203 20.00 15.00 10.00 13.00 La203 1.00 1.00 1.00 1.00 Na20 14.00 14.00 14.00 14.00 K20 3.00 3.00 3.00 3.00 Tip2 0.50 0.50 0.50 0.50 MgO 2.00 -2.00 7.00 2.00 A5203 0.50 050 0.50 0.50 CO2O3 0.001 0.001 0.001 0.001 Tg (° C) 628 565 564 557 Ew (° C) 840 780 740 740 VA (° C) 1267 1135 1060 1065 Hardness -2 without IA kp mm 520 550 520 520 with IA kp mm-2 630 660 530 530 Crystallization 60 min TB none none none none Layer thickness µm according to IA / 120 110 105 85 tension nm / cm 7000 7300 8100 4400 according to IA Man recognizes this very clearly that changes in the composition reduce the viscosity if the avoidance of crystallization remains the same, the additional increase is immediately achieved the Knoop hardness through the ion exchange (IA) can be nullified.

Der Ionenaustausch erfolgt in einem kaliumionenhaltigen Salzbad, z.B.The ion exchange takes place in a salt bath containing potassium ions, e.g.

KN03-Bad o.ä. unter an sich bekannten Bedingungen, z.B. während 8 Stunden bei 410 OC Die Messung der Austauschzone und der darin herrschenden Spannung erfolgt spannungsoptisch (siehe Gliemeroth, Glastechnische. Berichte 47 (1974) 97 bis 106).KN03 bath or similar under known conditions, e.g. during 8 Hours at 410 OC The measurement of the exchange zone and the tension in it takes place optically stress (see Gliemeroth, Glastechnische. Reports 47 (1974) 97 to 106).

Die Bestimmung des Viskositätsverhaltens erfolgt über die bekannten Fixpunkte Tg (= Transformationstemperatur), Ew (Erweichungstemperatur) und VA (= Verarbeitungstemperatur). Daraus läßt sich der Viskositätsverlauf nach der VFT-Gleichung für jede Temperatur zwischen 5 das und 1015 dPAs hinreichend-genau ermitteln und die Ziehfähigkeit für Glas dicken zwischen 0,5 und 1,5 mm mit etwa 4 x 103 dPas-bestimmen. Die genannten Glasdicken des gezogenen Glases sind die am häufigsten für Uhrgläser verwendeten Dicken (Maximum bei 0,8 mm). Andere Dicken sind ebenso ziehbar, was auf der günstigen Eigenschaft der erfindungsgemäßen Gläser beruht, nicht zu-kristall-isieren. (Eine Kristallisationsneigung im Ziehbereich führt zu Störungen, weil durch die auf der Ziehdüse aufwachsenden Kristalle die gezogene Glasoberfläche streifig wird.) Wegen der. extrem niedrigen Kristallisationsneigung der Gläser ist es möglich, das gezogene erfindungsgemäße Glas ohne nachträgliches Schleifen und Polieren direkt zu Uhrgläsern zu verarbeiten.The viscosity behavior is determined using the known ones Fixed points Tg (= transformation temperature), Ew (softening temperature) and VA (= Processing temperature). The viscosity curve can be derived from this according to the VFT equation determine with sufficient accuracy for every temperature between 5 das and 1015 dPAs and Determine the drawability for glass thicknesses between 0.5 and 1.5 mm with about 4 x 103 dPas. The mentioned glass thicknesses of the drawn glass are the most common for watch glasses used thicknesses (maximum at 0.8 mm). Other thicknesses can be drawn as well, what based on the favorable property of the glasses according to the invention not to crystallize. (A tendency to crystallize in the pulling area leads to disruptions because the crystals growing on the drawing nozzle, the drawn glass surface becomes streaky.) Because of the. extremely low tendency of the glasses to crystallize, it is possible that Drawn glass according to the invention without subsequent grinding and polishing directly to process into watch glasses.

Die Säurefestigkeit als extremes Maß für die chemische Beständigkeit ist bei den erfindungsgemäßen Gläsern besser als Klasse 2 nach DIN. Auch deutlich kürzere Ionenaustauschzeiten bis herab auf 1 Stunde, z.B. bei 4650 C ergeben beim erfindungsgemäßen Glas gute Biegezugfestigkeiten und eine erhöhte Knoop-Härte.Acid resistance as an extreme measure of chemical resistance is better than class 2 according to DIN for the glasses according to the invention. Also clearly shorter ion exchange times down to 1 hour, e.g. at 4650 C result in the Glass according to the invention good flexural strengths and an increased Knoop hardness.

Ausführungsbeispiel Es wird ein Glasgemenge aus folgenden Komponenten in Gewichtsteil.en eingewogen: Sand 1682,52 Borsäure 198,41 Al uminiummonhydrat 537,77 Lanthanoxid 28,18 Soda 641,95 Pottasche 641,95 Natriumsulfat 31,00 Magnesiumkarbonat 127,81 Rutil 14,10 Arsenoxid 14,03 Kobaltoxid 0,048 Das Glas wurde nach dem Einliegen der Komponenten gemischt, bei 13200 eingeschmolzen, durch Rühren homogenisiert, bei 11000 auf 0,9 mm ausgezogen und zu Rundscheiben mit 27 mm Durchmesser ausgeschnitten. Das Glas hatte einen nd von 1,508, einen AK von 90-,6 x 10-7 (20-3000C), einen Tg von 5670 C, einen Ew von 7820 C, einen VA von 11400 C und eine Knoop-Härte bei 200 g Last von 550 kp mm 2. Die Rundscheiben wurden gehärtet in einem KN03-Bad 16 Stunden bei 4000 C, danach hatte es eine Knoop-Härte von 660 kp mm 2 bei 200- g Last, eine Dicke der Drucksp«nnungszone von 110 /um, eine Druckspannung darin von 7300 nm/cm und eine Säure-Resistenz besser als Klasse 2. -EXEMPLARY EMBODIMENT The result is a batch of glass made up of the following components Weighed in in parts by weight: sand 1682.52 boric acid 198.41 aluminum monhydrate 537.77 Lanthanum Oxide 28.18 Soda 641.95 Potash 641.95 Sodium Sulphate 31.00 Magnesium Carbonate 127.81 rutile 14.10 arsenic oxide 14.03 cobalt oxide 0.048 The glass was placed after the inset the components mixed, melted at 13200, homogenized by stirring, at 11,000 pulled out to 0.9 mm and cut into round disks with a diameter of 27 mm. The glass had an nd of 1.508, an AK of 90-, 6 x 10-7 (20-3000C), a Tg of 5670 C, an Ew of 7820 C, a VA of 11400 C and a Knoop hardness of 200 g load of 550 kp mm 2. The circular disks were hardened in a KN03 bath for 16 hours at 4000 C, after that it had a Knoop hardness of 660 kp mm 2 at a load of 200 g, one Thickness of the compressive stress zone of 110 μm, a compressive stress therein of 7300 nm / cm and an acid resistance better than class 2. -

Claims (4)

Chemisch härtbares Uhrglas mit hoher Knoop-Härte Patentansprüche: ,, Silicatglas ur Abdeckscheiben mit einer Knoop-Härte über 500 kp mm bei 200 g Belastung, dadurch gekennzeichnet, daß es durch chemischen Ionenaustausch zu einer höheren Biegezugfestigkeit und auf eine Knoop-Härte von über 600 kp mm 2 härtbar ist, und daß es in Gew.-% folgende Zusammensetzung aufweist: SiO2 55 bis 68 B203 0 bis 6 # SiO2 + B2O3 + P2O5 55 bis 68 Al203 11 bis 21 La203 0 bis 2 # Al2O3 + La2O3 + TiO2 + ZrO2 + Nb2O5 11 bis 24 TiO2 0 bis 1 Na2O 9 bis 15 K20 1 bis 8 Alkalioxide 10 bis 18 MgO 0,5 bis 4 CaO 0 bis .2 Erdalkalien + ZnO 0,5 bis 6 Sonstige Oxide 0 bis 7. Chemically hardenable watch glass with high Knoop hardness Patent claims: ,, Silicate glass ur cover panes with a Knoop hardness over 500 kp mm at 200 g Load, characterized in that it becomes a chemical ion exchange higher flexural strength and hardenable to a Knoop hardness of over 600 kp mm 2 and that it has the following composition in% by weight: SiO2 55 to 68 B203 0 to 6 # SiO2 + B2O3 + P2O5 55 to 68 Al203 11 to 21 La203 0 to 2 # Al2O3 + La2O3 + TiO2 + ZrO2 + Nb2O5 11 to 24 TiO2 0 to 1 Na2O 9 to 15 K20 1 to 8 alkali oxides 10 to 18 MgO 0.5 to 4 CaO 0 to .2 alkaline earths + ZnO 0.5 to 6 Other oxides 0 to 7. 2. Silikatglas nach Anspruch 1, dadurch gekennzeichnet, daß es in Gew.-% folgende Zusammensetzung aufweist: SiO2 57 bis 63 B203 2 bis 6 Al203 14 bis 19 La2o3 0,2 bis 1,4 TiO2 0,1 bis 0,9 MgO 0,7 bis 2,5 CaO 0,1 bis 1,6 Na2O 9 bis 14 K20 0,3 bis 6 Sonstige Oxide, wie z.B. Läuter-, Färbe-und andere Oxide 0 bis 5.2. Silicate glass according to claim 1, characterized in that it is in % By weight has the following composition: SiO2 57 to 63 B203 2 to 6 Al203 14 to 19 La2o3 0.2 to 1.4 TiO2 0.1 to 0.9 MgO 0.7 to 2.5 CaO 0.1 to 1.6 Na2O 9 to 14 K20 0.3 to 6 Other oxides, such as refining, coloring and other oxides 0 to 5. 3. Glas nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es bis 1,5 Gew.-% Farboxide enthält.3. Glass according to claim 1 or 2, characterized in that it is up Contains 1.5% by weight of color oxides. 4. Glas nach Anspruch 3, dadurch gekennzeichnet, daß es zur Er-.4. Glass according to claim 3, characterized in that it is used for-. zielung einer blauen Farbtönung 0,0003 - '0,0014 Gew.-% Kobaltoxid enthält. Aiming for a blue tint 0.0003 - 0.0014% by weight cobalt oxide contains.
DE3212612A 1982-04-05 1982-04-05 Chemically hardenable watch glass with high Knoop hardness in the system SiO ↓ 2 ↓ -Al ↓ 2 ↓ O ↓ 3 ↓ -MgO-Na ↓ 2 ↓ O-K ↓ 2 ↓ O (-B ↓ 2 ↓ O ↓ 3 ↓ La ↓ 2 ↓ O ↓ 3 ↓) Expired DE3212612C2 (en)

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DE3212612A DE3212612C2 (en) 1982-04-05 1982-04-05 Chemically hardenable watch glass with high Knoop hardness in the system SiO ↓ 2 ↓ -Al ↓ 2 ↓ O ↓ 3 ↓ -MgO-Na ↓ 2 ↓ O-K ↓ 2 ↓ O (-B ↓ 2 ↓ O ↓ 3 ↓ La ↓ 2 ↓ O ↓ 3 ↓)
CH122483A CH662918GA3 (en) 1982-04-05 1983-03-07
JP58058839A JPS58185451A (en) 1982-04-05 1983-04-05 Chemically hardened watch glass with high hardness

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DE3212612A DE3212612C2 (en) 1982-04-05 1982-04-05 Chemically hardenable watch glass with high Knoop hardness in the system SiO ↓ 2 ↓ -Al ↓ 2 ↓ O ↓ 3 ↓ -MgO-Na ↓ 2 ↓ O-K ↓ 2 ↓ O (-B ↓ 2 ↓ O ↓ 3 ↓ La ↓ 2 ↓ O ↓ 3 ↓)

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JPH0444616B2 (en) 1992-07-22
CH662918GA3 (en) 1987-11-13
DE3212612C2 (en) 1985-12-19

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