United States Patent (19) 11) Patent Number: 4,662,952

Barringer et al. 45 Date of Patent: * May 5, 1987

54) NON-HYGROSCOPIC WELDING FLUX 56 References Cited
BNDERS U.S. PATENT DOCUMENTS
2,564,199 8/1951 Feldman ............................... 148/25
75) Inventors: Eric A. Barringer, Waltham; Thomas. 3,211,591 10/1965 Miltschitzky et al. ... 48/26
W. Eagar, Belmont, both of Mass. 3,301,688 1/1967 Simpelaar .............. ... 48/23
3,321,339 5/1967 Schulze ...... ... 148A23
73) Assignee: Massachusetts Institute of 3,328,212 6/1967 Coless ........ ... 148/26
Technology, Cambridge, Mass. 3,340,104 9/1967 Ballass et al. ... 148/26
3,468,999 9/1969 Hillert ........ ... 148/26
3,496,322 2/1970 Gonzalez ... ... 148A26
*) Notice: The portion of the term of this patent 3,597,285 8/1971 Aronberg.............................. 148/26
subsequent to Dec. 10, 2002 has been Primary Examiner-Peter D. Rosenberg
disclaimed.
Attorney, Agent, or Firm-Kenway & Jenney
(21) Appl. No.: 776,894 57 ABSTRACT
A welding flux binder and welding flux comprising the
22 Filed: Sep. 17, 1985 reaction product of a hydrolyzed and polymerized or
ganometallic compound selected from the group con
sisting of metal alkoxides including tetraalkylorthosili
Related U.S. Application Data cate, tetraalkylorthotitanate, tetraalkylorthozirconate
60 Continuation-in-part of Ser. No. 626,613, Jun. 29, 1984, and trialkylaluminate, metal esters, and metal oxalates.
Pat. No. 4,512,822, and Ser. No. 673,06, Nov. 19, The organometallic compound is hydrolyzed and then
1984, Pat. No. 4,557,768, which is a division of Ser. No. polymerized to form a gel glass phase. Alkali and alka
626,613. line earth salts are added to stabilize and reduce the
viscosity of the gel. The resulting welding flux binder
51) Int. Cl." .............................................. B23K 35/34 and flux are non-hygroscopic and have a high fired
(52). U.S. C. ........................................ 148/23; 148/24; strength.
148/25
58 Field of Search ..................................... 148/23-25 23 Claims, No Drawings
 4,662,952
1. 2
these fluxes at 1100° C. is that metallic powders, which
NON-HYGROSCOPC WELDING FLUX BNDERS may be added to provide alloying of the weld metal,
oxidize during the baking operation.
BACKGROUND OF THE INVENTION In U.S. Ser. No. 626,613, now U.S. Pat. No. 4,512,822
5 issued Apr. 23, 1985, and U.S. Ser. No. 673,016, appli
This application is a continuation-in-part of U.S. Ser.
No. 626,613 filed June 29, 1984, now U.S. Pat. No. cants disclosed a welding flux binder hydrolyzed and
4,512,822 issued Apr. 23, 1985, and the divisional appli polymerized from a mixture of tetraalkylorthosilicate,
cation, U.S. Ser. No. 673,016 filed Nov. 19, 1984. Si(OR)4, wherein R is -CH3, -C2H5 or -C3H7, alkali
The present invention is in the general field of weld 10
and alkaline earth salts. The welding flux made with the
ing flux binders and in particular discloses a non-hygro binder comprises an alkali-alkaline earth silicate,
scopic welding flux binder formed from a hydrolyzable M2O.M"O.SiO2, wherein M is lithium, sodium potas
organometallic compound. sium, or other element in Group I of the Periodic Table
Fluxes are utilized in arc welding to control the arc and M' is magnesium, calcium, barium, or other element
stability, modify the weld metal composition, and pro in Group II of the Periodic Table and may further com
vide protection from atmospheric contamination. Arc 15
prise metal compounds. About 5-10% of the weld flux
stability is controlled by modifying the composition of mixture consists of weld flux binder, with the flux mak
the flux. It is therefore desirable to have substances ing up the remainder.
which function well as plasma charge carriers in the Tetraalkylorthosilicate is an organometallic precur
flux mixture. Fluxes modify the weld metal composition sor to a ceramic binder. The organic portion is removed
by rendering impurities in the metal more easily fusable 20
and by providing substances which these impurities during processing of the weld flux binder and is not
may combine with, in preference to the metal, to form present in the final product. Unlike the prior art welding
slag. Fluxes are prepared with a higher or lower per flux binders, the binder contains a homogeneous distri
centage of acidic or basic compounds depending on the bution of alkali and alkaline earth ions and is not hygro
type of metal to be welded and impurities in the metal. 25 scopic. This is a result of the use of tetraalkylorthosili
In some instances, other materials may be added to cate and the presence of compounds which react to
lower the slag melting point and improve slag fluidity, form CaO, MgO, BaO, or other alkaline earth oxides.
and to serve as binders for the flux particles. The oxide compounds, particularly calcium com
Hydrogen embrittlement is a phenomenon which pounds, act as stabilizing agents and make the fired
involves loss of ductility and increased crack suscepti 30 binder non-hygroscopic. Alkali compounds, particu
bility in steel at room temperature due to the presence larly potassium, significantly reduce the viscosity of the
of hydrogen in the steel. Hydrogen induced cracking glass, lowering the temperature required to sinter the
will occur to some extent whenever sufficient hydrogen binder.
and stress are present in a hard steel at temperatures It is therefore an object of the present invention to
above - 100° C. and below 150 C. As it is almost im 35 provide a non-hygroscopic welding flux binder and
possible to avoid producing these stresses in a weld, welding flux.
methods of crack control usually involve controlling It is another object of the present invention to pro
the amount of hydrogen present in the weld, the micro vide a welding flux binder and welding flux which can
structure of the solidified weld metal, or both. Hydro be produced and processed at a temperature less than
gen can be introduced into the weld arc atmosphere 1000 C. so that compounds of low stability such as
from a number of sources including oxides, wire con carbonate may be included.
taminants and oil. The primary source is moisture in the It is another object of the invention to provide a
flux and flux binder, which attaches the flux to the versatile welding flux binder which allows incorpora
outside of a shielded metal arc weld electrode. tion of temperature sensitive alloy powders or other
Most welding electrode flux formulations consist of 45 materials into the flux.
an oxide-based flux and additives bonded together by It is a still further object of the present invention to
sodium silicate. Sodium silicate binders have two im provide a welding flux binder which produces a weld
portant disadvantages. They are very hygroscopic and ing flux with relatively high fired strength.
they require moisture to keep them sound and free from
cracks. During welding, the heat evaporates and disso 50 SUMMARY OF THE INVENTION
ciates the water, evolving hydrogen gas which dis A welding flux binder and welding flux comprising
solves into the metal. Under stress, the dissolved hydro the reaction product of a hydrolyzed and polymerized
gen may produce cracks with the potential for cata organometallic compound such as a metal alkoxide, a
strophic failure. In an effort to decrease the possibility metal ester, or a metal oxalate. In the present invention,
of failure, sodium silicate welding electrodes are dried 55
the welding flux binder is formed by hydrolyzing the
at 1100 C. to decrease the water content of the flux to
less than 0.2%. The dried electrodes can then be used organometallic compound and then polymerizing to
for only a limited time before the flux again absorbs form a gel glass phase. In the preferred embodiment, the
moisture from the air and has to be redried. organometallic compound is tetraalkylorthosilicate or
A second problem with sodium silicate weld fluxes is 60 tetraalkylorthotitanate. Calcium is added to the binder
their lack of a CO2 generating compound. CO2 aids in mixture to stabilize the binder, and to make the gel
operability of the flux by increasing the stability of the soluble in water and chemically resistant by blocking
arc and by excluding atmospheric contamination, par the structure and suppressing diffusive processes. Potas
ticularly N2, from the metal. Drying the electrodes at sium is added to significantly reduce the viscosity of the
1100 C. decomposes CO2 sources such as calcium car 65 glass, thereby lowering the temperature required to
bonate, but does not allow diffusion of the calcium into sinter the binder.
the sodium silicate to form an intimate mixture which is The welding flux binder is formed using a sol-gel
non-hygroscopic. Another problem with drying of process comprising:
 4,662,952 4.
3
(1) dissolving an organometallic compound, or mix materials. The process is based on the polymerization of
tures thereof, in an organic solvent such as alcohol; organometallic compounds with metal salts. The or
(2) adding elements from Group I and Group II of the ganometallic compound and metal salts are dissolved in
Periodic Table to water, wherein the sources of the a solvent, then the metal compound/metal salt solution
alkali and alkaline earth ions are compounds soluble in is hydrolyzed to initiate a polymerization or condensa
alcohol, such as nitrates, iodides, salicylates, acetates tion reaction, wherein either water or alcohol is elimi
and carbnates of sodium, potassium, lithium, magne nated, thereby producing a gel. The gel is dried to pro
sium, calcium, barium, and combinations thereof; duce a powder which can be sintered to form a glass or
(3) combining the organometallic solution with the ceramic.
water-ion solution; 10 There are two main reactions involved in the sol-gel
(4) optionally adding metal carbonates, fluorides, process. These are (1) hydrolysis of the metal com
flux, reactive metals, and other solids; pound/metal salt solution and (2) polymerization of the
(5) mixing the solution until a gel forms; solution to form a gel. These reactions proceed simulta
(6) drying the gel; and neously and their extent and rate of reaction depend on
(7) sintering the dried gel, usually at a temperature 15 a number of variables, including quantity of water, pH,
between 500 and 1100 C.
There are a number of variables in the production of temperature, time of reaction and type of reacting spe
C1S.
welding flux binders using a sol-gel process. Examples
of variables include the particle size and size distribu The welding flux binder of the present invention
tion of the organometallic compound, relative concen 20 contains a homogeneous distribution of alkali and alka
tration of reagents, presence of impurities in the rea line earth ions due to the reaction involving the organo
gents, the hydrolysis time, the pH of the hydrolysis metallic compound and is non-hygroscopic due to the
solution, and the time and temperature at which the formation of CaO, MgO, BaO, or other oxides formed
binder and flux are sintered. When hydrolysis is rela from Group II elements. The primary importance of
tively fast, large, condensed polymers are found during 25 this is that it reduces the incidence of hydrogen embrit
gelation. When the gels with large, condensed polymers tlement in the weld made using either the shielded metal
are allowed to dry, they form a low density, coarse gel. arc welding (SMAW) process or the submerged arc
Low density gels require higher temperatures to sinter welding process (SAW). Unlike sodium silicate binders,
and densify than high density gels. Other variables in the binder of the present invention contains a homoge
clude the mole percent alkali or alkaline earth ions such 30 neous mixture of metal ions with the other binder com
as potassium or calcium. For example, an excess of ponents. The alkaline earth oxide compounds, particu
calcium in the binder can lead to weak binding of the larly calcium compounds, act as stabilizing agents and
flux particles. make the fired binder non-hygroscopic by making the
DETAILED DESCRIPTION OF THE gel insoluble in water and chemically resistant by block
INVENTION 35 ing the structure to diffusive processes. The alkali com
pounds, particularly potassium, significantly reduce the
The present invention is a welding flux binder and a viscosity of the glass, lowering the temperature re
welding flux containing the sintered binder which is the quired to sinter the binder.
reaction product of at least one organometallic com In the preferred embodiment of the welding flux, the
pound such as a metal ester, a metal alkoxide, or a metal 40 organometallic compound is reacted by first dissolving
oxalate. In the preferred embodiment, the organometal the compound in alcohol and then adding water to
lic compound is an alkoxide precursor to a ceramic hydrolyze the organometallic compound. Alkali and
binder such as tetraalkylorthosilicate (TAOS) or tet alkaline earth metals, such as nitrites, iodides, salicy
raalkylorthotitanate (TAOT). The organometallic com lates, acetates and carbonates of sodium, potassium,
pound is hydrolyzed and polymerized with elements 45 lithium and calcium or other Group I and Group II
selected from Group I and Group II of the Periodic elements, are added to the hydrolyzed organometallic
Table. The weld flux made with the disclosed binder compound. Metal carbonates, fluorides, flux and other
has the following formula: solids are added to make the suspension approximately
10-50% solids. The suspension is neutralized, usually by
50 addition of a base such as ammonium hydroxide, cast
wherein M is lithium, sodium, potassium or other ele into a mold, and dried. The gel product is then sintered.
ment in Group I of the Periodic Table, The organic portion of the organometallic compound is
M" is magnesium, calcium, barium or other element in removed in processing of the welding flux and is not
Group II of the Periodic Table, and present in the final product. In the final processed prod
wherein N is silicon, titanium, zirconium or aluminum 55 uct, the binder comprises about 5-10% of the total
and mixture and the flux plus other solid additions makes up
X is between 1 and 2. the remainder.
Examples of metal alkoxides useful in the present A number of materials may be included in the flux
invention include tetraalkylorthosilicate, tetraalkylor such as manganese oxide (MnO), silicone dioxide
thotitante, tetraalkylorthozirconate, and trialkylalumi 60 (SiO2), zirconium oxide (ZrO2), titanium oxide (TiO2),
nate, wherein the alkyl group is -CH3, -C2H5, fluorite (CaF2), alumina (Al2O3), magnesia (MgO), iron
-C4H9 or -C3H7. Examples of metal esters include oxide (Fe0), barium oxide (BaO), and calcia (CaO). A
metal acetates such as aluminum acetate, aluminum commercially available MnO-SiO2 flux is Linde 80 TM,
acetylacetonate, or aluminum butoxide. Examples of manufactured by Union Carbide, New York, NY, in
metal oxalates include titanium oxalate and zirconium 65 various particle sizes. Other solids which may be added
oxalate. to the flux material and binder, typically in an amount
The sol-gel process is a chemical method for making up to 50%, include any power which is insoluble in
ceramics or high purity, highly homogeneous oxide alcohol, including reactive metals such as iron, manga
 4,662,952
5 6
nese, copper chromium, nickel, aluminum, titanium, 100 minutes, 50 mls. of ammonium hydroxide were
vanadium, niobium, boron or compounds thereof. Dop added to samples 5-8.
ants may also be added to the gel phase during the Samples 9-12 were prepared in the same manner as
hydrolysis and polymerization of the organometallic sample 4. 2.02 g potassium nitrate and 3.49 g calcium
compound. nitrate were added to the nitric acid solution, mixed
The invention will be further understood from the well, and then added to the TEOS-alcohol solution.
following non-limiting examples, demonstrating the The hydrolyzed TEOS-ion solution was thoroughly
effect of order of addition of the various components of mixed with 230 g of Linde 80TM flux. Sample 9 con
the welding flux binder and relative ratios of the binder tained 200 mesh flux, sample 10 contained 100 mesh
components and their effect on the properties of the O flux, and sample 11 contained 60 mesh flux. Sample 12
final fired products, and clearly establishing the non contained 0.8 g calcium carbonate in addition to the
hygroscopicity of the weld binder of the present inven potassium nitrate and calcium nitrate, for a final calcium
tion relative to commercially available binders. concentration of 8.7 mol percent. After adding the
In example 1, the sensitivity of the hydrolysis reac Linde 80TM flux particles, the mixture was poured into
tion to the presence of the acid catalyst was demon 15 a beaker containing 50 mls of ammonium hydroxide and
strated using welding flux binders prepared with the an additional 50 mls of ammonium hydroxide was im
same gel composition but hydrolyzed for different mediately added to this solution.
lengths of time to determine the effect on final water Immediately upon addition of the ammonium hy
retention. The components are shown in Table I. droxide, a white, non-uniformly textured gel formed,
TABLE 1 20
interspersed with excess ammonium hydroxide. The gel
Sample 2 3 4. 5 6 7 8 structure was very coarse. The samples were allowed to
ns. TEOS 50 50 50 50 50 50 50 50 air dry for 4 days. The dried gel was sintered at 700° C.
mis. ethyl
alcohol
27 27 27 27 27 27 27 27 for 2 hours in a cleaned and weighed porcelain crucible
nks. distilled 35 35 35 35 35 35 35 35 25 using a preheated furnace. The fired samples were
Water tested for hygroscopicity by exposure to 95-99% hu
drops nitric 0 0 10 10 10 10 10 10 midity at 50° C. over a period of 4 days. For purposes of
acid
g. KNO3 - 2.02 - 2.02 - 2.02 - 2.02
comparison, two commercial welding flux and binder
(potassium systems are also tested for their hygroscopic properties.
nitrate) 30 The first was a typical cellulose-bound electrode (6011)
g. CaNO3 ww-- - 3.49 3.49 - 3.49 3.49 and the second a low-hydrogen electrode (7018). Sam
(calcium ples of the flux, Linde-80 TM, mesh sizes, 200, 100, and
nitrate)
mis. NH4OH 50 50 50 50 50 50 50 50 60, were tested as controls.
(ammonium The amount of adsorbed water was determined by
hydroxide) 35 measuring the weight differential after exposure to high
Sample 9 10 11 2 humidity for four days and then firing at 200° C. for 2
ms. TEOS 50 50 50 50 hours. The samples were fired at 700° C. for an addi
mls. ethyl 27 27 27 27 tional two hours to remove chemically absorbed water.
alcohol
mis. distilled 35 35 35 35
Again, the weight differential before and after firing
Water was determined to yield the weight percent chemically
drops nitric O 10 10 O absorbed water. The results of the hygroscopic testing
acid are shown in Table II.
g. potassium 2.02 2.02 2.02 2.02 Samples 9, 10 and 11 were measured using a Pycnom
nitrate
g. calcium 3.49 3.49 3.49 3.49 eter to determine if the different flux particle sizes af.
nitrate 45 fected the amount of water retention by the sintered
g, calcium
carbonate
0.8 flux. Measurement of the surface areas per gram for
g. Linde 80 TM each sample were calculated and used to determine the
200 mesh 230 density of the flux.
100 mesh 230 TABLE II
60 mesh 230 50
mls, annonium 100 00 100 Physically Adsorbed Chemically Absorbed
hydroxide Water loss Water loss
Sample Weight Percent Weight Percent
1 2. 357
Solutions consisting of a mixture of 50 mls. of tet 2 O.S 192
raalkylorthosilicate (TEOS) and 27 mls. of ethyl alco 55 3 2. 1427
hol and solutions consisting of 35 mls. distilled water 4.
5
1.8
1.6
.06
7.791
with 10 drops of nitric acid were prepared. Potassium 6 1.1 62
nitrate and calcium nitrate were added to the acid-water 7 4.3 1570
solutions as follows: Samples 1 and 5 contain no potas 8 0.6 523
sium nitrate nor calcium nitrate. Samples 2 and 6 con 60 9 ,044 023
tain 8 mol percent potassium. Samples 3 and 7 contain 6 10 048
050
008
.01
mol percent calcium. Samples 4 and 8 contain 8 mol 12 .6 770
percent potassium and 6 mol percent calcium. The acid 13 26. 21.64
water-ion solutions were then mixed with the TEOS 4. 5.6 136
alcohol solutions. Each mixture was shaken vigorously 65 15
6
03
02
O
O
and allowed to stand for 40 minutes while the TEOS
17 . O
hydrolyzed at a pH of 1.5. After 40 minutes, 50 mls. of
ammonium hydroxide were added to samples 1-4. After
 4,662,952
7 8
The composition of samples 1-12 in Table II is shown at least one element in Group II of the Periodic Ta
in Table I. Sample 13 is the commercially available ble.
cellulose-bound electrode (6011) and sample 14 is the 2. The welding flux binder of claim 1 wherein the
commercially available low-hydrogen electrode (7018). organometallic compound is selected from the group
Samples 15, 16, and 17 are the Linde 80 TM flux, mesh consisting of tetraalkylorthosilicate, tetraalkylorthotita
sizes 200, 100, and 60, respectively. nate, tetraalkylorthozirconate, trialkylaluminate, and
The results shown that the level of adsorbed water combinations thereof.
generally rises slowly with increasing surface area but is 3. The welding flux binder of claim 2 wherein the
affected by the presence of calcium ions. When Samples alkyl group is selected from -CH3, -C2H5, -C4H9
9, 10 and 11 are compared, there is a almost linear rela O and -C3H7.
tionship between adsorbed water and particle size. As 4. The welding flux binder of claim 1 wherein the
particle diameter decreases, so does the level of ad organometallic compound is a metal oxalate, wherein
sorbed water. The resistance of the smaller particle size the metal is selected from the group consisting of alumi
system to adsorption is probably due to tighter packing num, zirconium, silicon, titanium, and combinations
of flux particles and consequently improved sintering. 15 thereof.
As is readily apparent, the levels of adsorbed water for 5. The welding flux binder of claim 1 wherein the
each of the Samples 1-12 is considerably less than for organometallic compound is a metal acetate, wherein
the standard commercial cellulose flux and binder, Sam the metal is selected from the group consisting of sili
ple 13, and significantly less than for the commercial con, titanium, aluminum, zirconium and combinations
low-hydrogen flux and binder, Sample 14. 20 thereof.
The samples incubated for 40 minutes, Samples 1-4, 6. The welding flux binder of claim 1 wherein the
show much lower chemically absorbed water levels element in Group I is selected from the group consisting
than samples incubated for 100 minutes, Samples 5-8. of potassium, lithium, sodium, or combinations thereof.
The lowest amount of absorbed water is for Sample 4, a 7. The welding flux binder of claim 1 wherein the
combination of TEOS, potassium nitrate and calcium 25 element in Group II is selected from the group consist
nitrate. This sample showed a weight loss of only 0.016 ing of clacium, magnesium, barium, and combinations
weight percent. When the TEOS binders were com thereof.
bined with the Linde 80TM flux, the weight percent 8. The welding flux binder of claim 3 comprising
water loss ranged from a low of 0.008 for the sample between 6 and 8 mol percent potassium and calcium.
containing only the calcium nitrate to a high of 0.023 30 9. A welding flux comprising a compound of the
weight percent for the sample containing only the po formula
tassium ions. As shown by Sample 12, increasing the
calcium content increases the amount of absorbed water
loss.
These results significantly contrast with the weight 35 wherein:
percent water loss of 0.136 for the commercial low M is selected from the elements in Group I of the Peri
hydrogen flux and binder of Sample 14 and even more odic Table,
significantly with the commercially available cellulose
bound flux and binder of sample 13, which showed a M" is selected from the elements in Group II of the
water of 21.64 weight percent. There is no measurable 40 Periodic Table, and
water absorption by the flux itself. N is selected from the group consisting of silicon, tita
As shown by Sample 4, the presence of both potas nium, aluminum, zirconium, and combinations
sium and calcium ions decreases the amount of water thereof, and
absorption by the welding flux binder. The potassium X is between 1 and 2,
ions form a potassium silicate with the silica, which has 45 wherein said compound is the reaction product of a
a lower sintering temperature than does plain silica. The hydrolyzed, polymerized organometallic compound
lowered sintering temperature allows the binder to selected from the group consisting of metal esters, metal
densify with a relatively low surface area. The calcium alkoxides, metal oxalates and combinations thereof.
ions also form a calcium silicate which is non-hygro 10. The welding flux of claim 9 wherein M is selected
scopic and blocks water molecules from approaching 50 from the group consisting of potassium, sodium, lith
the relatively hygroscopic potassium silicate, further ium, and combinations thereof.
reducing the level of absorbed water. The addition of 11. The welding flux of claim 9 wherein M' is selected
sodium nitrate along with the calcium and potassium from the group consisting of calcium, magnesium, bar
nitrates may be used to further reduce the required ium, and combinations thereof.
sintering temperature. 55 12. The welding flux of claim 9 wherein the organo
Although this invention has been described with metallic compound is selected from the group consist
reference to specific embodiments, it is understood that ing of tetraalkylorthosilicate, tetraalkylorthotitanate,
modifications and variations may occur to those skilled tetraalkylorthoziconate, trialkylaluminate, and combi
in the art. It is intended that all such modifications and nations thereof.
variations be included within the scope of the appended 60 13. The welding flux of claim 9 wherein the organo
claims. metallic compound is a metal oxalate, wherein the metal
What is claimed is: is selected from the group consisting of aluminum, zir
1. A welding flux binder comprising: conium, silicon, titanium, and combinations thereof.
an organometallic compound selected from the group 14. The welding flux binder of claim 9 wherein the
consisting of metal esters, metal alkoxides, metal 65 organometallic compound is a metal acetate, wherein
oxalates, and comminations thereof, the metal is selected from the group consisting of sili
at least one element in Group I of the Periodic Table; con, titanium, aluminum, zirconium and combinations
and thereof.
 4,662,952
10
15. The welding flux of claim 9 further comprising at metal esters, metal oxides, metal alkoxides, and
least one metal oxide. combinations thereof;
16. The welding flux of claim 15 wherein the metal (2) preparing an aqueous suspension of compounds
oxide is selected from the group consisting of magne selected from the group consisting of the elements
sium oxide, silicon dioxide, zirconium oxide, titanium 5
in Group I and Group II of the Periodic Table;
oxide, alumina, magnesia, iron oxide, barium oxide and (3) forming a gel by combining the organometallic
calcia. solution with the aqueous solution to hydrolyze
17. The welding flux of claim 9 further comprising a and polymerize the organometallic compound; and
fluoride compound. (4) drying the gel.
18. The welding flux of claim 9 further comprising at 21. A process for making a non-hygroscopic welding
least one metal powder. flux according to claim 20 further comprising adding
19. The welding flux of claim 18 wherein the metal compounds selected from the group consisting of metal
powder is selected from the group consisting of iron,
manganese, chromium, nickel, aluminum, titanium, va oxides, metal carbonates, fluoride compounds, metal
nadium, niobium, copper, and boron. 15 powders, flux particles and combinations thereof.
20. A process for making a non-hygroscopic welding 22. The process of claim 21 further comprising sinter
flux binder comprising: ing the welding flux.
(1) dissolving an organometallic compound in an 23. The process of claim 22 wherein the welding flux
organic solvent, wherein said organometallic com is sintered at a temperature between 500' and 1100° C.
pound is selected from the group consisting of 20 2 k

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