Crystallizing glass solders and stripping films with such glass solder imprinted thereon

FIELD OF THE INVENTION 
This invention relates to partially crystallizing glass solders which, in 
powder form, are suitable for low fusion tension and mechanically strong 
bonding of materials with thermal expansions of -5 to 
+33.multidot.10.sup.-7 .multidot.K.sup.-1 in the temperature range of 
20.degree.-500.degree. C. such as quartz glass, transparent glass ceramics 
containing h-quartz mixed crystals, opaque glass ceramics containing 
h-spodumenes as well as borosilicate glasses, e.g., of the DURAN 50 type 
with an .alpha.-value in the range of 20.degree.-300.degree. C. of 
33.multidot.10.sup.-7 .multidot.K.sup.-1.

SUMMARY AND DESCRIPTION OF THE INVENTION 
The glass crystal compositions consist of 50-90 weight percent of the 
h-quartz mixed crystal phase of the system Li.sub.2 O--Al.sub.2 O.sub.3 
--SiO.sub.2 and 10-50 weight percent of the glass phase of components not 
integrated into the h-quartz mixed crystal lattice such as boric acid 
(B.sub.2 O.sub.3), lead oxide (PbO), sodium oxide (Na.sub.2 O), potassium 
oxide (K.sub.2 O), fluorine (F) and an amount of a nucleation agent up to 
4 weight percent of titanium oxide (TiO.sub.2). In addition, the soldering 
glasses can contain up to 2 percent magnesium oxide (MgO) and cobalt oxide 
(CoO) forming mixed crystal. A B.sub.2 O.sub.3 content of at least 3 
weight percent, preferably &gt;5.0 weight percent, proved to be a 
prerequisite for a technically suitable bonding strength of such a fusion 
(soldering). 
By means of the glass phase portion it is possible during the melting 
process between 1420.degree. and 1300.degree. C. to stabilize the pure 
h-quartz mixed crystal composition with the mole-ratio Li.sub.2 O:Al.sub.2 
O.sub.3 :SiO.sub.2 =1:1:2; i.e. 11.86 weight percent Li.sub.2 O, 40.46 
weight percent Al.sub.2 O.sub.3, 47.68 weight percent SiO.sub.2, which has 
a strong tendency toward crystallization, so that the solders can be 
melted in a homogeneous glassy state and be processed to glass powder. 
A granulation of &lt;100 .mu.m, preferably &lt;20 .mu.m, has proven to be 
effective for soldering. The glass solder powders are used either in paste 
form or as a 10 to 250 .mu.m, preferably 25 to 100 .mu.m, screen printing 
layer for the soldering process. 
The invention generally relates to a partially crystallizing glass solder 
which exhibits, after having been sintered at a temperature lower than 
900.degree. C., preferably lower than 850.degree. C., from glass powder 
smaller than 100 .mu.m, thermal expansion coefficients in the range of 
20.degree.-500.degree. C. from -23.5 to 34.3.multidot.10.sup.-7 
.multidot.K.sup.-1, differential thermoanalysis peak.sub.max temperatures 
(at a heating rate of 2.7 K/min or 6 K/min) lying below 710.degree. C. and 
crystal phases consisting predominantly of h-quartz mixed crystal phase, 
and which contain, calculated as oxide weight percents, 23.0-44.0 Wt. % 
SiO.sub.2, 20.0-37.0 Wt. % Al.sub.2 O.sub.3, 5.5-11.0 Wt. % Li.sub.2 O, 
3.0-20.0 Wt. % B.sub.2 O.sub.3, 0-36.0 Wt. % PbO, 0-1.0 Wt. % Na.sub.2 O, 
0-1.5 Wt. % K.sub.2 O, 0-0.1 Wt. % F, 0-4.0 Wt. % TiO.sub.2, 0- 3.5 Wt. % 
MgO, 0-2.0 Wt. % CoO and 8.5-50.0 Wt. % in total of the combination of 
B.sub.2 O.sub.3, PbO, Na.sub.2 O, K.sub.2 O, F and TiO.sub.2. All of the 
solders according to this invention may contain small amounts of 
unavoidable impurities. 
The glass solders of this invention which are preferably suitable for 
soldering quartz glass, transparent and opaque glass ceramics in the 
SiO.sub.2 --Al.sub.2 O.sub.3 --Li.sub.2 O system, exhibit in the sintered 
crystalline state thermal expansion coefficients in the range of 
20.degree.-500.degree. C. from -23.5 to +26.multidot.10.sup.-7 
.multidot.K.sup.-1, differential thermoanalysis peak.sub.max temperatures 
(at a heating rate of 2.7 K/min) lying below 700.degree. C. and crystal 
phases consisting predominantly of h-quartz mixed crystal phase, and 
contain, calculated as oxide weight percents, 35.0-44.0 Wt. % SiO.sub.2, 
30.0-37.0 Wt. %, Al.sub.2 O.sub.3, 8.5-11.0 Wt. % Li.sub.2 O, 3.0-10.0 Wt. 
% B.sub.2 O.sub.3, 0-15.0 Wt. % PbO, 0-1.0 Wt. % Na.sub.2 O, 0-0.65 Wt. % 
K.sub.2 O, 0-0.1 Wt. % F, 0-4.0 Wt. % TiO.sub.2, 0-2.0 Wt. % MgO, and 
8.5-25.0 Wt. % in total of the combination of B.sub.2 O.sub.3, PbO, 
Na.sub.2 O, K.sub.2 O, F and TiO.sub.2. 
One solder which is preferable for use in soldering the transparent glass 
ceramic ZERODUR, for example, exhibits in the sintered crystalline state a 
progression of the thermal expansion coefficient in the range of 
20.degree.-500.degree. C. from -5.3 over -0.7 to +13.3.multidot.10.sup.-7 
.multidot.K.sup.-1, a differential thermoanalysis peak.sub.max temperature 
lying at 687.degree. C., the crystalline phase consisting predominantly of 
h-quartz mixed crystal, and having a fusion tension in ZERODUR lying 
between 180 and 210 nm/cm of pressure tension, the tensile strength being 
greater than 15 N/mm.sup.2 and the modulus of elasticity lying between 
10,000 and 20,000 N/mm.sup.2. This solder consists essentially of, 
calculated as oxide parts by weight, 43.71 parts SiO.sub.2, 35.43 parts 
Al.sub.2 O.sub.3, 10.17 parts Li.sub.2 O, 8.95 parts B.sub.2 O.sub.3, 1.60 
parts PbO, 0.04 parts Na.sub.2 O, 0.10 parts F, 4.00 parts TiO.sub.2, 
making a total of 104.00 parts by weight. 
Another glass solder which is preferably suitable for the soldering of 
borosilicate glasses of the DURAN 50 type exhibits in the sintered 
crystalline state at a maximum of 680.degree. C. thermal expansion 
coefficients in the range of 20.degree.-400.degree. C. from 11.9 to 
34.3.multidot.10.sup.-7 .multidot.K.sup.-1, differential thermoanalysis 
peak.sub.max temperatures (at a heating rate of 6 K/min) lying below 
710.degree. C. and a crystalline phase consisting predominantly of 
h-quartz mixed crystal phase together with somewhat lesser proportions of 
an unknown second crystalline phase (that is, it shows two differential 
thermoanalysis peaks). This solder contains, calculated as oxide weight 
percents, 23.00-29.00 Wt. % SiO.sub.2, 20.00-25.00 Wt. % Al.sub.2 O.sub.3, 
5.90-7.00 Wt. % Li.sub.2 O, 10.00-20.00 Wt. % B.sub.2 O.sub.3, 12.50-36.00 
Wt. % PbO, 0-1.50 Wt. % K.sub.2 O, 4.00 Wt. % TiO.sub.2, 0-3.50 Wt. % MgO, 
0-2.00 Wt. % CoO and 40.00-50.00 Wt. % in total of the combination of 
B.sub.2 O.sub.3, PbO, K.sub.2 O and TiO.sub.2. 
A particularly preferable embodiment of this glass solder, preferably 
suitable for the soldering of DURAN 50 glass, exhibits in the sintered 
crystalline state a change of the thermal expansion coefficient in the 
range of 20.degree.-400.degree. C. from 18.9 to 29.4.multidot.10.sup.-7 
.multidot.K.sup.-1, the fusion tension in a 5-layer soldering test using 
this solder corresponds to the curve progression shown in drawing FIG. 3, 
and the tensile strength of this soldering is &gt;15 N/mm.sup.2. This solder 
consists essentially of, calculated as oxide weight percents, 28.70 Wt. % 
SiO.sub.2, 24.30 Wt. % Al.sub.2 O.sub.3, 7.00 Wt. % Li.sub.2 O, 20.00 Wt. 
% B.sub.2 O.sub.3, 14.00 Wt. % PbO, 4.00 Wt. % TiO.sub.2 and 2.00 Wt. % 
MgO. 
The invention of this application also encompasses the use of the glass 
solder as described herein to solder various glasses, particularly quartz 
glass, and transparent and opaque glass ceramics in the SiO.sub.2 
--Al.sub.2 O.sub.3 --LiO system. The soldering may take place using a 
pressure greater than 500 g/cm.sup.2 on the soldered surface and the 
soldering may be carried out on hollow bodies where the soldering pressure 
is produced by the use of a vacuum within the hollow body itself. The 
soldering may take place below 900.degree. C., and preferably below 
850.degree. C. 
The glass solders according to this invention may also be used as elements 
of a stripping film, which comprises a backing of a coated paper and a 
layer of an agent applied by means of an adhesive, preferably a 
water-soluble adhesive, in which the agent to be transferred to another 
object is a glass solder, a crystallizing glass solder, a partially 
crystallized glass solder or a mixture of these materials. The agent to be 
transferred by the stripping film may be applied to the film by means of 
screen printing, offset printing or a combined screen/offset printing in a 
predetermined thickness. The agent to be transferred is particularly a 
partially crystallizing glass solder whose crystal phase consists 
predominantly of h-quartz mixed crystals, and which consists essentially 
of, calculated as oxide weight percent, 23.0-44.0 Wt. %, SiO.sub.2, 
20.0-37.0 Wt. % Al.sub.2 O.sub.3, 5.5-11.0 Wt. % Li.sub.2 O, 3.0-20.0 Wt. 
% B.sub.2 O.sub.3, 0-36.0 Wt. % PbO, 0-1.0 Wt. % Na.sub.2 O, 0-1.5 Wt. % 
K.sub.2 O, 0-0.1 Wt. % F, 0-4.0 Wt. % TiO.sub.2, 0-3.5 Wt. % MgO and 
0-2.0 Wt. % CoO. 
The soldering process comprises the following stages: 
vaporization of the paste solvent, 
nucleation of the h-quartz mixed crystal phase, 
sintering or soldering and crystallization of the h-quartz mixed crystal 
phase in the system Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2. 
Evaporation of the solvent takes place during the heating process below 
500.degree. C. Nucleation and crystallization take place between 
550.degree. and 850.degree. C. A longer holding time at temperatures above 
650.degree. C. in the case of borosilicate glasses and 780.degree. C. with 
quartz and glass ceramics serves for soldering or sintering. 
Two characteristic programs for soldering of transparent glass ceramics 
containing h-quartz mixed crystals, e.g., ZERODUR are: 
Program I: 
##STR1## 
(RT=room temperature) 
Program II: 
##STR2## 
Program III has proved effective for borosilicate glass soldering: 
##STR3## 
In the case of fusion processes for transparent glass ceramics, which take 
place below 850.degree. C., it is advantageous to carry out the soldering 
under pressure. It has been observed that a pressure of .gtoreq.500 
g/cm.sup.2 substantially enhances the mechanical strength of the 
soldering. The pressure can be achieved by exterior stress as well as by 
the application of a vacuum in the case of hollow bodies. The soldering 
process must be carried out at temperatures below 900.degree. C., since 
the h-quartz mixed crystal is converted into spodumenes having 900.degree. 
C. For a mechanically tight borosilicate bond a soldering under pressure 
has shown itself to be effective. Testing of the strength of each solder 
is performed with L-shaped fusion samples stressed above a bending stress 
to breaking. Strength values of 10-24 N/mm.sup.2 result for suitable 
solders. 
The stresses which can occur in the solder layer and in the fusion partner 
consist of diffusion stresses and/or fusion stresses. The diffusion 
stresses are brought about by an ion exchange between the solder and the 
fusion partner. The magnitude of the diffusion stress and the depth of the 
stress layer are, as is known, dependent on the differing chemical 
potential of the two bond partners, the temperature and the diffusion 
time. In the case of not overly long diffusion times (hour), with solder 
layers of .gtoreq.100 .mu.m, the diffusion stress profiles are independent 
of the thickness of the solder layer. The magnitude of the fusion stress 
is determined by the thermal expansion differences of the fusion partners 
in the fusion zone and the "transition temperature," which can be equated 
with the Tg temperature of the solder as a first approximation at slow 
cooling. The diffusion stress, as a rule, can be easily measured since 
after a brief tempering period of a few hours (e.g. according to Program 
I), the diffusion layer is only a few .mu.m (5-100 .mu.m) thick. The 
stress occurring in this thin diffusion layer is usually greater than the 
fusion stress. As a result, the stress in the diffusion layer can be 
equated with the diffusion stress. 
The glass solder 1 of Table 1 produces in the surface layer of ZERODUR, in 
case of a tempering according to Program I in a layer thickness of 30 
.mu.m, a pressure tempering of 2,500 nm/cm or 83 N/mm.sup.2. In contrast 
to such fusion stresses, diffusion pressure stresses are desirable in the 
surface layer of the fusion partner, since they enhance the mechanical 
strength of the fusion. 
The fusion stress can be determined only indirectly in the presence of the 
diffusion stress. For this purpose, two 1 mm thick samples of the fusion 
partners (e.g. ZERODUR) are provided on each side with a solder layer. One 
of the two samples is provided with 100 .mu.m and the other with a 200 
.mu.m thick solder layer and tempered according to Program I. After taking 
into account the diffusion stress there results for the fusion stress, 
with the 100 .mu.m sample, a pressure stress of 40 nm/cm and with the 200 
.mu.m sample of 80 nm/cm over the entire breadth of 1 mm. Relative to the 
same thickness of solder and fusion partner (ZERODUR), this means a fusion 
stress of 200 nm/cm or 6.7 N/mm.sup.2. 
The temperature dependence of the stresses generated during soldering is of 
great importance in the case of optical applications, e.g. for telescope 
mirrors. The temperature dependencies of the stresses within the interior 
of the fusion partner (ZERODUR) are represented for the glass solders 1 
through 4,6 and 8 in FIG. 1. FIG. 2a shows the test samples used for this 
purpose. A 1.times.10.times.10 mm thick ZERODUR platelet (1) is soldered 
on both sides with solder layers (3) of over 60 to 80 .mu.m thick to two 
0.5.times.10.times.10 mm large ZERODUR platelets (2); (4) indicates the 
direction of measurement. 
The following are significant for the evaluation and choice of the solders: 
1. Sufficient crystallization stability during the fusion, so that the 
solders can be produced in the glassy state. 
2. The devitrification characteristic of the glass solder, determined by 
means of differential thermoanalysis (DTA) on powder &lt;20 .mu.m, a a 
heating rate of 2.7 K/min for the glass ceramic and quartz glass solders 
and 6 K/min for the borosilicate glass solders. Qualitative information on 
the crystallization behavior is obtained from the peak.sub.max, the peak 
height and the peak surface. 
3. The termal expansion coefficient of the crystallized solder after the 
fusion process. For this purpose glass powder &lt;20 .mu.m is moistened with 
distilled water and pressed to a rod 125.times.12.times.10 mm and sintered 
in accordance with the above mentioned Program I. From this, the 
individual thermal expansion coefficients in the range of 
50.degree.-500.degree. C. are determined, as is the crystal phase content 
of the samples by X-ray. 
4. For the strength of the bond, an L-sample is produced. The vertical arm 
is firmly clamped and the horizontal arm stressed. The solder binding the 
vertical and horizontal arms should exhibit a fusion strength of 
&gt;10N/mm.sup.2, preferably &gt;15N/mm.sup.2. The rupture generally occurs in 
the fusion partner and not in the solder layer. 
It is of decisive importance in the composition range of the solders for 
the transparent glass ceramics, that the h-quartz mixed crystal phase 
should always crystallize out during the fusion process, this being well 
known to have a heavily negative thermal expansion. For the PbO-richer 
borosilicate glass solders, an additional unknown Pb-silicate phase 
occurs. With respect to the positive thermal expansion of the variable 
glass phase occurring simultaneously, the thermal expansion of these 
partially crystallizing solders can thus be modified in both positive and 
negative directions. 
For the suitability as fusion solder for transparent glass ceramics with 
h-quartz mixed crystal phase (ZERODUR), the low maximal crystallization 
temperature of &lt;700.degree. C.--determined as a peak.sub.max from the 
differential thermoanalysis--is an absolute requirement. At higher fusion 
temperatures &gt;900.degree. C. the h-quartz mixed crystal phase would 
rearrange into h-spodumenes and thus bring about opacity and an increase 
in the thermal expansion coefficients of the fusion partner. 
From this it can be seen that these solders are suitable at the same time 
for bonding of materials such as quartz glass and opaque glass ceramics 
containing h-spodumenes with thermal expansion coefficients of about +6 to 
+20.multidot.10.sup.-7 .multidot.K.sup.-1 in the temperature range of 
20.degree.-500.degree. C. 
In Table 1 which follows, nine composition examples are indicated and in 
Table 2 the significant properties of these solders which characterize the 
suitable composition range of the glass ceramic and quartz glass solders 
as follows: 
______________________________________ 
SiO.sub.2 35.77-43.71 
Wt. %, 
Al.sub.2 O.sub.3 30.34-36.50 
Wt. %, 
Li.sub.2 O 8.89-10.60 
Wt. %, 
B.sub.2 O.sub.3 3.00-10.00 
Wt. %, 
PbO 0-15.00 Wt. %, 
Na.sub.2 O 0-1.00 Wt. %, 
K.sub.2 O 0-0.65 Wt. %, 
F 0-0.10 Wt. %, 
MgO 0-2.00 Wt. %, 
TiO.sub.2 0-4.00 Wt. %, 
B.sub.2 O.sub.3 + PbO + Na.sub.2 O + 
8.50-25.00 
Wt. %. 
K.sub.2 O + F + TiO.sub.2 
______________________________________ 
TABLE 1 
__________________________________________________________________________ 
Weight Percent Composition Examples 1- 9 
Components 
1 2 3 4 5 6 7 8 9 
__________________________________________________________________________ 
SiO.sub.2 
43.71 
42.90 
42.90 
42.90 
38.20 
38.20 
43.70 
42.90 
35.77 
Al.sub.2 O.sub.3 
35.43 
35.00 
36.50 
36.50 
32.40 
32.40 
35.42 
34.50 
30.34 
Li.sub.2 O 
10.17 
10.60 
10.60 
10.60 
9.40 
9.40 
10.17 
10.60 
8.89 
B.sub.2 O.sub.3 
8.95 
10.00 
8.50 
10.00 
3.00 
6.00 
8.95 
8.50 
6.00 
PbO 1.60 
0.75 13.00 
10.00 
1.00 15.00 
Na.sub.2 O 
0.04 1.00 
K.sub.2 O 0.65 
F 0.10 
MgO 0.75 
1.50 2.00 
TiO.sub.2 
4.00 4.00 
4.00 
4.00 
4.00 
1.50 
4.00 
Percent Total 
104.00 
100.00 
100.00 
105.00 
100.00 
100.00 
104.00 
100.00 
100.00 
__________________________________________________________________________ 
TABLE 2 
__________________________________________________________________________ 
Properties of Glass Solders of Table 1 
Properties 1 2 3 4 5 6 7 8 9 
__________________________________________________________________________ 
(in glassy state) 
.alpha. .multidot. 10.sup.7 (20-300.degree. C.)/.degree.C. 
72.1 74.0 73.0 76.8 72.9 74.4 75.3 
TG (.degree.C.) 
542 536 550 537 545 531 509 
Density (g/ccm) 
2.456 2.410 
2.424 2.427 2.443 2.430 
2.768 
in sintered crystalline state 
.alpha. .multidot. 10.sup.7 
(20-50.degree. C.)/.degree.C. 
-5.3 -2.78 
-6.72 -0.60 
+1.2 -0.3 -14.1 -6.2 +4.77 
(20-100.degree. C.)/.degree.C. 
-4.5 -3.05 
-6.84 -0.80 
+3.1 +2.6 -17.1 -23.5 
+8.33 
(20-150.degree. C.)/.degree.C. 
-1.4 -0.80 
-4.22 +2.50 
+5.1 +5.1 -11.6 -19.6 
+11.06 
(20-200.degree. C.)/.degree.C. 
+0.7 +1.43 
-1.36 +5.90 
+7.1 +7.5 -7.0 -14.3 
+13.17 
(20-250.degree. C.)/.degree.C. 
+3.6 +3.25 
+0.97 +8.80 
+9.1 +9.4 -3.3 -10.3 
(20-300.degree. C.)/.degree.C. 
+4.2 +5.11 
+2.96 +11.10 
+10.8 +10.8 
+0.02 -7.4 +16.06 
(20-400.degree. C.)/.degree.C. 
+8.1 +7.28 
+5.57 +14.40 
+12.4 +13.1 
+5.6 +0.7 +18.02 
(20-500.degree. C.)/.degree.C. 
+13.3 +13.69 
+8.83 +22.90 
+16.4 +16.4 
+13.6 +6.9 +25.88 
E-modulus (N/mm.sup.2) 
12000 11900 
12500 
DTA 
Peak.sub.max (.degree.C.) 
687 678 679 661 658 660 685 611 638 
Peak height (mm) 
56 23 22 60 85 90 62 72 84 
Peak surface (mm.sup.2) 
1070 676 680 880 1700 1510 1020 1625 1520 
Crystal phase 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
content MK MK MK MK MK MK MK MK MK 
(84%) + 
(86%) + 
(85%) + 
(87%) + 
(78%) + 
(90%) + 
(89%) + 
(92%) 
(89%) + 
unknown 
unknown 
unknown 
unknown 
unknown 
unknown 
unknown 
unknown 
unknown 
Phase Phase 
Phase Phase 
Phase Phase 
Phase Phase 
Phase 
Strength of 17.2 19.9 21.6 23.0 23.3 22.0 20.9 22.2 21.4 
ZERODUR Solderings 
18.0 17.7 22.4 17.9 22.0 14.1 17.0 20.3 21.8 
(N/mm.sup.2) 17.5 17.9 19.5 16.9 23.6 
__________________________________________________________________________ 
Table 3 contains the composition examples 10-17 of partially crystallizing 
solders for borosilicate glass with an .alpha.-value of 
33.multidot.10.sup.-7 .multidot.K.sup.-1 in the range of 
20.degree.-300.degree. C. In Table 4 are indicated the most important 
properties of these solders. The most favorable composition range for 
these solders has proven to be as follows: 
______________________________________ 
SiO.sub.2 23.85-28.70 
Wt. %, 
Al.sub.2 O.sub.3 20.25-24.30 
Wt. %, 
Li.sub.2 O 5.90-7.00 Wt. %, 
B.sub.2 O.sub.3 10.00-20.00 
Wt. %, 
PbO 12.50-36.00 
Wt. %, 
K.sub.2 O 0-1.50 Wt. %, 
TiO.sub.2 4.0 Wt. %, 
MgO 0-3.50 Wt. %, 
CoO 0-2.00 Wt. %, 
B.sub.2 O.sub.3 + PbO + Na.sub.2 O + 
40.00-50.00 
Wt. %. 
K.sub.2 O + F + TiO.sub.2 
______________________________________ 
TABLE 3 
__________________________________________________________________________ 
Weight Percent Composition Examples 10- 17 
Components 
10 11 12 13 14 15 16 17 
__________________________________________________________________________ 
SiO.sub.2 
28.70 
28.70 
23.85 
28.70 
28.70 
28.70 
28.70 
28.70 
Al.sub.2 O.sub.3 
24.30 
24.30 
20.25 
24.30 
24.30 
24.30 
24.30 
24.30 
Li.sub.2 O 
7.00 
7.00 
5.90 
7.00 
7.00 
7.00 
7.00 
7.00 
B.sub.2 O.sub.3 
10.00 
20.00 
10.00 
10.00 
20.00 
20.00 
20.00 
20.00 
PbO 26.00 
16.00 
36.00 
25.00 
14.00 
12.50 
12.50 
12.50 
K.sub.2 O 1.00 1.50 
TiO.sub.2 
4.00 
4.00 
4.00 
4.00 
4.00 
4.00 
4.00 
4.00 
MgO 2.00 
2.00 
3.50 
1.50 
CoO 2.00 
Percent Total 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
__________________________________________________________________________ 
TABLE 4 
__________________________________________________________________________ 
Properties of Glass Solders of Table 3 
Properties 10 11 12 13 14 15 16 17 
__________________________________________________________________________ 
(in glassy state) 
.alpha. .multidot. 10.sup.7 (20-300.degree. C.)/.degree.C. 
78.1 71.2 78.0 79.2 70.5 73.8 70.7 70.5 
TG (.degree.C.) 
463 467 457 453 478 469 479 478 
Density (g/ccm) 
3.046 2.725 3.116 3.020 2.711 2.676 2.697 2.711 
in sintered crystalline state 
.alpha. .multidot. 10.sup.7 
(20-50.degree. C.)/.degree.C. 
11.9 15.5 14.2 14.2 18.9 13 15.4 14.8 
(20-100.degree. C.)/.degree.C. 
14.4 17.9 17.2 15.7 19.8 22.8 20.7 19.4 
(20-150.degree. C.)/.degree.C. 25.5 23.1 21.8 
(20-200.degree. C.)/.degree.C. 
19.8 22.1 22.7 20.5 24.2 27.8 25.3 24.0 
(20-250.degree. C.)/.degree.C. 29.6 27.0 25.7 
(20-300.degree. C.)/.degree.C. 
23.3 25.3 26.1 23.5 27.0 31.3 28.5 27.3 
(20-400.degree. C.)/.degree.C. 
26.0 28.0 28.1 25.8 29.4 34.3 31.4 30.2 
E-modulus (N/mm.sup.2) 
DTA 
Peak.sub.max (.degree.C.) 
580 & 675 
560 & 691 
550 & 630 
550 & 620 
582 & 700 
603 & 705 
585 & 700 
530 & 710 
Peak height (mm) 
9 & 22 
9 & 13.5 
6 & 37 
6,5 & 47 
9 & 16 
10 & 13 
7 & 15 8 & 18 
Peak surface (mm.sup.2) 
330 & 810 
300 & 635 
130 & 995 
155 & 955 
225 & 825 
335 & 745 
200 & 670 
350 & 800 
Crystal phase 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
h-Quartz- 
content MK MK MK MK MK MK MK MK 
(54%) + 
(46%) + 
(59%) + 
(56%) + 
(48%) + 
(48%) + 
(53%) + 
(46%) + 
unknown 
traces 
unknown 
Pb-- unknown 
TiO.sub.2 
unknown 
unknown 
Phase unknown 
Phase Titanat + 
Phase + Phase + 
Phase 
Phase + unknown 
TiO.sub.2 TiO.sub.2 
TiO.sub.2 Phase 
Strength of borosilicate 
15.9 15.2 16.5 16.6 16.7 12.8 15.2 
glass-(Duran) solderings 
17.1 16.5 14.2 15.2 16.7 13.8 12.0 
15.5 17.0 16.4 16.2 12.5 17.0 
__________________________________________________________________________ 
FIGS. 3 and 4 show the resulting fusion tension in nm/cm on the basis of 5 
layer bond samples of glass solders 12, 14 with DURAN 50 borosilicate 
glass in the median D-50 glass sample during the heating-fusion process of 
0.degree.-600.degree. C. and the subsequent cooling to room temperature. 
The structure of these fusion samples can be seen from FIG. 2b. Three 
1.times.10.times.10 mm DURAN platelets (5) are fused over two solder 
layers (6) of 1.times.10.times.10 mm. The arrow (4) in FIG. 2b indicates 
the direction of measurement. 
The two solders used are best suited for soldering of borosilicate glasses 
of the DURAN 50 type at maximal fusion temperatures of 680.degree. C. 
These partially crystallizing glass solders may also be used on stripping 
films which employ glass solder as the agent which is to be transferred 
from the film to another object. Stripping films find application in many 
fields. For example, stripping films for decorating bowls, plates and 
other chinaware are well known. These stripping films consist of a backing 
of coated paper upon which a decorative color is applied by means of a 
water-soluble adhesive. To decorate the china, the film is soaked, the 
transfer image withdrawn, applied to the china and baked on. 
By using a stripping film one may easily transfer a layer of glass solder, 
crystallizing glass solder or a mixture of such materials to objects which 
are to be bonded together by means of this glass solder. The glass solder 
layer thus forms the "decal" of a traditional transfer film. 
The glass solder is applied preferably by means of screen printing, offset 
printing or a combination of screen/offset printing to the backing which 
generally consists of coated paper. The glass solder layer is of any 
desired thickness and advantageously has a thickness of from 100 to 250 
.mu.m. A preferred glass solder is a partially crystallizing glass solder 
whose crystal phase consists predominantly of h-quartz mixed crystals and 
which consists, calculated as oxide weight percent, of the following: 
______________________________________ 
SiO.sub.2 23.0-44.0 Wt. %, 
Al.sub.2 O.sub.3 20.0-37.0 Wt. %, 
Li.sub.2 O 5.5-11.0 Wt. %, 
B.sub.2 O.sub.3 3.0-20.0 Wt. %, 
PbO 0-36.0 Wt. %, 
Na.sub.2 O 0-1.0 Wt. %, 
K.sub.2 O 0-1.5 Wt. %, 
F 0-0.1 Wt. %, 
TiO.sub.2 0-4.0 Wt. %, 
MgO 0-3.5 Wt. %, 
CoO 0-2.0 Wt. %, 
B.sub.2 O.sub.3 + PbO + Na.sub.2 O + 
8.5-50.0 Wt. %. 
K.sub.2 O + F + TiO.sub.2 
______________________________________