DE2003332A1 - Composite structure - Google Patents

Description

Soh / Ql M 2074

Haveg Induetries, Inc., Wilmington, Delaware 19808 / USA Network structure

Pie invention relates to a metal object that has a Has upper suction on a gemieohten crystalline glass, and also refer to a method of making the same.

aiasemailUberstge or glass-like enamelUberattge can be used often applied to metal objects, for example made of steel, to prevent corrosion of the metal base. When carrying out the usual CHaebesohiohtungsrerfahren the glass frit is used together with a grinding grade B. onto the surface of the steel in the form of a casting compound or slurry applied. After drying the

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Casting compound, the coated object is heated or fired to an elevated temperature, this temperature generally being between 816 and 982 ⁰ O (1500 and 1800 ° p). The glass is melted in the process. .

Silicon dioxide is the main component of most glasses. If the object coated with glass is exposed to strongly corrosive media during its use, a high silicon dioxide level of 70-85% is aimed for, since silicon dioxide increases the resistance of the glass to chemical attack.

It is also known that a deglazed glass is a good one Sonlag and Sohook resistance as well as excellent toughness owns. In general, however, there is a lack of Glasten glass is corrosion-resistant, because the deglazed parts consist mainly of silicon dioxide, while the amorphous glass matrix, which consists of silicon dioxide is impoverished, has poor resistance to corrosive attack.

Bs has already been proposed, a glass fring with a high Combine silicon content and good corrosion resistance with a devitrifiable glass frit to create one Glass coating to get together, which has good impact resistance old has good corrosion resistance. In carrying out a procedure of this type, it was common practice to the corrosion-resistant glass frit with the devitrifiable glass frit to marry and the mismatched kicks on the metal to bring up the object. After the burning of the coated objects, the objects coated with glass are used to melt the glass Subject to further heat treatment at one temperature below the firing temperature to keep the

BATH ORIGINAL

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subjected to devitrified particles. As a result of this concluding send heat treatment, a pulp phase system is generated, that of 1. the amorphous glass matrix of devitrifiable glass, which is then done by removing the deglazed particles is depleted in silicon dioxide, 2. consists of devitrified particles and 3. corrosion-resistant glass. Sa the amorphous glass matrix that is exhausted of silicon dioxide, has poor corrosion resistance, the coating has poor corrosion resistance.

It has also already been proposed to use metal objects both with a devitrifiable glass and with a corrosion-resistant one To cover glass. A process of this type is described in US Pat. No. 3,361,588 the implementation of which the steel is initially coated with a devitrifiable glass, which is then subjected to heat treatment is relieved. A corrosion-resistant glass frit is then applied to the degassed glass and then fired. A process of this type, however, requires two separate heat treatments of the metal object or vessel, so that the overall costs of the process are increased.

The present invention relates to a method for coating a metal object, the obtained crystalline glass coating not only provides improved impact ability and toughness, but also has excellent corrosion resistance. According to the invention a devitrifiable glass frit is first dry-ground and thereafter heat-treated at an elevated temperature for a period of time sufficient to substantially do so to completely defrost the Pritte. Pie devitrification has the development of tiny silica crystals in it

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a matrix of amorphous glass to follow. Ansohlieesend on the devitrification will wet the devitrified frit with a Usual corrosion-resistant glass frit that has a, high Percentage, tz contains of silicon dioxide, grind. The ground Slurry is applied to the metal object. After drying, the item is at an increased Temperature fired for a time sufficient to melt the glass.

The devitrifiable step is a standard glass frit that is used during the heat treatment can be deglazed. You devitrifiable pritte can be composed, for example, as follows (Jewiohts- ^):

Ll ₂ O 1 - 25 #

Al ₂ O ₃ 0 - 30 yrs

SiO ₂ 60 - 80 Jt Na ₂ O 0 - 5 #

HgO 0 - 5 f>

CeO ₂ 0-10 *

0 - 5 #

₂ 0 - 5 *

FbO 0 - 5 f>

OaO 0-10 years

Specific examples of frits that can be deglazed and falling under the above composition are given below (Oowiohte-jC);

111

15.0 1.5 8.0 ₂₅ 25.0 - 2.0

SiO ₂ 60.0 75.0 75 »O

009831/1683

ORIGINAL INSPECTED

JL 2

MgO CeO

5.0 - 3.0 5.0 8.5 - Μ » 5.0 5.0 - 4.0 -

ZrO ₂
PbO
OaO - - 9.0

The devitrifiable frit is first dry in the usual way grind · The xellohen size of the grinded frit is not critical, but generally greater than 0.50 mm (less than 59 mesh).

Subsequent to milling, the frit is heated to an elevated temperature for a period of time sufficient to substantially completely devitrify the frit. The devitrification but eligible temperatures and tents depend on the composition of the frit, but the temperatures are generally zwiwohen 558 and 871 ° 0 (1000 and 1600 ⁰ P) lie. The times observed at such temperatures usually vary between 1 and 2 hours. During this heat treatment, silicate particles crystallize out of the amorphous glass matrix. There are two ways of kriotallizing or deglazing the fully devitrifiable part of the frit. In most cases, the crystals do after fax BntglAsung least 50 öewichts-jS and very often 60 ■> 85 ^ weighted entglastext the frit.

The devitrified crystals must be less than 10 and most «they have a rope size between 0.1 and 2.0 and on.

0 0 98 31/1683 bad original

Subsequent to the devitrification, the devitrified frit is made Grind wet with a corrosion-resistant glass frit and a Mahlaueatz. The corrosion-resistant oil fry can be composed as follows (weight ^):

SiO ₂ 63 - 80 f>

TiO ₂ 0-2 $

g 0 - 8 #

QaO 0 - 2 #

Li ₂ O 1-5 $

Na ₂ O 8 - 17 f>

K ₂ O 0 - 7 #

NgO 0-2 Si

ϊ ₂ ° - 3 *

ÖOO 0 - 1.25 *

MnO 0 - $ 1.50

HiO 0 - $ 1.50

Specific examples of corrosion-resistant frits which fall under the composition given above,

the ones given below (weights- ^):

SiO ₂ TlQ ₂

1 ι 72.5 73.5 75.0 1.0 - - £, 0 5.5 4.5 1.0 2.0 1.5 2.5 3, e 3.0 17.5 14.0 12.5

GaO

Li ₂ O Ia ₂ O

MgO, I ₈ O - 1.0

J ₂ «2, C

öoO 0.5-0.5

MnO 1.0-0.5

NlO 1.0-0.5

009831/1613

In most cases the corrosion-resistant glass frit is used a non-devitrifiable frit »However, this is not essential. The third corrosion resistant can to some extent be relieved. Even if the corrosion-resistant frit Can be t-glassed, it will not be devitrified during the burning period, and »was therefore not because the metal object is not held at the firing temperature for a period of time sufficient to allow devitrification deglass corrosion-resistant frit.

The milling additives that are added to the glass frit are the usual additives, for example sodium nitrate, Bentonite, sodium aluminate, clay or the like.

The devitrifiable frit makes up to 60% dry weight Frittmieohung and preferably 20-50 # of the dry mixture aue.

The glazed step · as well as the corrosive permanent glass frit are preferably ground wet in the form of an aqueous suspension. In some cases, however, the two fries also dry-wed and soldered onto the metal object applied in the form of a dry dust cover will. The particle size «of the ground frit mixture is not critical. It corresponds to what is usually used in enamel technology Partial height adhered to. Generally go up to 85 * of the ground frit particles through a sieve with a clear Masohen world of 0.075 mm (200 mesh) through.

The wet grinding · Frittenmieohung can be on the metal base be applied in the usual way, namely by applying, dipping, floating, brushing or like that. Bach of application to the metal base will

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- 8 the coating dried by evaporation of the water.

For the metal backing, ee can be around steel or around any act as another metal with a coefficient of thermal expansion similar to that of steel. In particular The metal base can be made of mild steel such as SAB 1010-1030, stainless steel, Inconel, Hastalloy C-276 or the like.

The metal base coated with glass is ^{fired at a temperature between 460 and 927 0} O (1400-1700 ⁰ P). Usually, the firing is carried out at a temperature of 816-871 ⁰ C (1500-1600 ⁰ P), during a period of about 5-15 minutes. The glass is melted onto the metal. During the firing, the amorphous glass matrix of the enamelable frit tends to dissolve in the corrosion-resistant glass, so that the amorphous glass matrix, which is exhausted of silicon dioxide, is eliminated aneolilically in the glass coating obtained a mixture of the corrosion-resistant glass and the glass matrix of the devitrifiable steps. Since the glass matrix of the devitrifiable steps is not present as a separate phase in the end product, the corrosion resistance of the glass coating is noticeably improved. The presence of the devitrified particles improves: the heat resistance as well as the toughness of the glass. Glass over-

The devitrification of the devitrifiable 31as frit prior to application The step on the metal object enables a wider range of heat treatment to be maintained than the DurohXUhrung of stained glass. If the Pritte on the metal object is naoh the firing, then leave to the heat treatment

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limited as it is not possible »some metal parts heat treat for extended periods of time without obstruction. ·

Another disadvantage of the previously known methods! at whose implementation the devitrification was then carried out, After the glass has been applied to the respective metal object, some ropes of the The object is heated to a different temperature than other parts, with the result that the Devitrification in the glass occurs to varying degrees. There are various physical properties in the Obtaining glass suction »This problem is invented by the invention eliminated as the pritte as such before application the respective object is devitrified, so that the object is not subjected to a lengthy anti-vitrification heat treatment will.

If the steps as such are subjected to a stained glass " Heat treatment, then it is also possible to use more refractory treads that contain higher levels of silicon dioxide contain and set aside higher glazing temperatures, su can use Hcoliffeete preparations not to be used if the defrosting is then carried out is after oils cold on the respective object has been applied since a long er & iteen on the high discharge * temp he; · in disadvantageous catfish the physical signatures of the ßegenatirad can.

Specific examples Fuif atm "rflnduasgegfimäase be below

0QSI31 / 1SS3 BAD ORIGINAL

example 1

A devitrifiable frit is produced which has the following composition (in Gewiohts-jS):

Li ₂ O 8.0

j 2.0

75.0

MgO ** 3.0

TiO ₂ 3.0

OaO 9 * 0

J) Ie steps are ground and heated as such to a temperature of 732 ⁰ O (135O 3?) And kept at this temperature for a period of 1 1/2 hours to devitrify the frit. Following the devitrification, the third air is cooled to room temperature.

40 parts of the deglazed steps are ground with 60 parts of a cor * roelons-resistant oil aa frit ta, ®iaem Mahleueat «from 3 T '" lan clay, 0.2 part of salt and 0.1 part of sodium aluminate and parts of water.

JÜ · Corrosion-resistant glass rides have the following composition (in Oewiohts ~ ^) s

1 * 0 4.0 1.0 2.3

S, 0

t, o 009831/1683

CoO 0.5

MnO 1.0

KIO 1f0

When carrying out the Hassmilling process, the degassed frit and the milling additives are initially melted for a period of 1 hour, after which the corrosion-resistant plate is added and the milling is continued for a further 11/2 hours. After milling, the Seilohen Pritt the mixture have such a large that less than $ 3> of a sieve with an aperture of 0.075 mm Hash are retained (200 mesh).

The ground casting compound is applied to the primed Surface of a JPlufi steel plate sprayed on and under Infrared lamps dried.

After the coated plate Srooknen this (P 1540 ⁰⁾ fired at a temperature of 838 ° C for a period of 9 minutes.

The coated steel plate obtained has good impact and sohook resistance and excellent Resistance to erosion

Example 2

Eb a detachable step is made, including the following Composition (in Oewichts-jt) has:

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- 12 Li ₂ O 8.0

₂ O ₃ 2.0

SiO ₂ 75.0

MgO 3.0

TiO ₂ 3.0

CaO 9.0

The frit is heated and milled as such to a temperature of 843 ° C (1550 ⁰ P) and maintained at this temperature for a period of 11/2 hours to devitrification of the frit. After the deglazing, the frit is cooled in the air to room temperature.

30 parts of the devitrified frit are combined with 70 parts of a corrosion-resistant glass frit, a grinding additive Parts of clay, 0.2 parts of setite and 0.1 part of sodium aluminate and grind 43 parts of water.

The corrosion-resistant glass frit has the following composition (in weight 8-56):

SiO ₂ 73.5

ZrO ₂ 5.5

CaO 2.0

Li ₂ O 3.0

Na ₂ O 14.0

F ₂ 2.0

When performing the nasal milling process, the devitrified frit and milling additives are initially used during a Tent failure of 1 hour melted, whereupon the corrosion · »

009831/1583

constant treads are added and milling is continued for an additional 11/2 hours. After grinding, the particles of the ritten mixture are of such a size that less than 3 % is retained by a sieve with a height of 0.075 mm (200 mesh).

The ground casting compound is then attached to the primed Surface of a Flufi steel plate sprayed on and under Infrared lamps dried.

The one obtained, provided with a crystalline glass teal eye Steel plate has good impact and eye-hook resistance as well as excellent corrosion resistance.

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Claims (16)

Claims Alliance structure door made of a metal base and a frit mass that flioh on one surface of the backing is, thereby identified, that the frit mass from a mixture from a) a deglazed glass frit an amorphous glass matrix, which has a considerable proportion of contains devitrified crystalline particles, and b) there is a corrosion-resistant glass frit, the ritten mass then at an elevated temperature sum Sohmelaen the hatred has been burned to the metal, and the amorphous glass matrix tends to dissolve in the corrosion-resistant glass frit during firing bu, 2. Structure naoh claim 1, characterized in that the deglazed oil frits up to bu 60 $ έ of the riding mass. 3. Structure according to claim 1, because it is known that the deglazed oil frit 20-50 ounces of the pritten mass ausmaoht. 4. Structure according to claim 1, including the fact that the corrosion-resistant glass contains 63-80% silicon dioxide. 5. Structure according to Anspruoh 1, characterized in that the deglazed ropes size at least 50 fi of the deglazed glass frit. 6. Structure according to Claim 5, because it indicates that the crystalline particles have a size of less than 1 u own. 009831/1583 7. Structure according to claim 4, characterized in that the metal base consists of a ferrous metal. 8. Composite structure of a metal base and a mixed one Frit mass, which is located on a surface of the support, characterized in that the mass from a mixture of a) a deglazed glass frit an amorphous glass matrix in which finely divided deglazed Crystalline lights are contained, the deglazed Particles more than 50 $ the weight of the devitrified glass frit make up, and b) a corrosion-resistant glass frit, the devitrified glass frit up to 60 weight β- ^ of the frit mass, and the composite structure subsequently to an elevated temperature sum melting the Iittenstoff has been melted to the base, wherein the glass matrix tends to dissolve in the corrosion-resistant glass frit during firing. 9. A method for coating a metal object, thereby characterized in that a devitrifiable glass frit for obtaining a devitrified third from an amorphous glass matrix and a multitude of devitrified crystalline particles, which are distributed within the matrix is devitrified, the devitrified glass frit with a corrosion-resistant glass frit is mixed to obtain a mixture, the mixture is applied to the metal object and the Object is heated to a temperature sufficient to melt the cold on the metal object, wherein The amorphous glass matrix tends to turn out to be corrosion-resistant Dissolve glass frit during firing. 10. The method according to claim 8, characterized in that the devitrifiable glass frit by heating to a temperature 009831/1583 is degassed from 538 - 871 ⁰ O (1000 - 160O ⁰ F). 11. The method according to claim 9, characterized in that the deglazed frit makes up to 60 weight ^ of the Mlsohung. 12. The method of claim 9 _t characterized "in that the mixing is carried out to each other by grinding the frit, wherein the! Feilchen the ground mixture have a particle size such that at least 85 Ί" the particles passes a sieve with a mesh size of 0.075 mm (200 mesh) go through it. 13. The method according to claim 12, characterized in that the mixed mixture is applied to the object in the form of an aqueous slurry. 14. The method according to claim 12, characterized in that the water after application to the item is removed prior to firing. 15. The method according to claim 9, characterized in that the metal object is ^{fired at a temperature between 760 and 927 ° C (1400-1700 0} F). 16. A method of coating a steel substrate, thereby characterized that a deglaobable glass frit on a Temperature is heated, which is sufficient to devitrify the frit, the devitrified frit from an amorphous Glaematrix consists in which a multitude of deglazers Crystals is contained and the crystals account for at least 50 wt. B-56 of the devitrified frit that devitrified 009831/1583 Frit is mixed with a corrosion resistant Eritte, wherein the devitrified Pritte 20 - constitutes 50 weight ^ of the mixture, bringing the mixture to the steel backing on "and the steel base to a i'emperatur 760-927 ⁰ O (1400 - 1700 ⁰ P) is heated during a span sufficient to melt the third, the amorphous glass matrix clasu tending to dissolve in the corrosion-resistant gray surface resulting from the burning. 009831/158 3 BATH ORIGINAL