Abstract: A flux composition for brazing of an aluminum material which can feed a proper amount of flux to an area to be joined at the time of brazing and at the same time can improve working environment, and a method for brazing of an aluminum material. The method comprises: coating an aluminum material to be joined with a flux composition comprising 0.5 to 25 parts by weight of a polymeric compound having a number average molecular weight of 50000 to 5000000 and comprising repeating alkylene oxide units, 5 to 30 parts by weight of a fluoride flux, and water added in such an amount as will provide a total amount of the composition of 100 parts by weight; heating the coated area to remove water; heating the coated area to decompose and remove the polymeric compound; and then conducting heating for brazing.

Abstract: A fluxing composition is disclosed. The composition comprises a high molecular weight carboxylic acid that forms a combination of carboxylate salts and unreacted acid anhydrides when applied to a solder alloy and exposed to temperatures in the range of about 150 to 350.degree. C. in an inert atmosphere and a carrier fluid comprising a mixture of organic solvents that is heat stable and non-reactive with the solder alloy and has a high viscosity at room temperature. Also disclosed is an integrated circuit assembly comprising an integrated circuit comprising a chip attached to a substrate by a plurality of solder joints and a thin layer of a residue comprising the carboxylate salts and acid anhydride. The film of residue is formed concomitantly with the formation of the solder joints during the reflow cycle. Since the residue is reactive with an epoxy used in bonding the chip to the substrate, the usual process step of cleaning the flux residue prior to dispensing the epoxy is obviated.

Abstract: A soldering flux containing borneol, which is also referred to as bornyl alcohol. A method soldering using such a flux is also disclosed. Even minor proportions of borneol in the flux help reduce ionic residue from the flux after soldering. Larger proportions of borneol can give the flux tackiness for wave soldering operations. The flux preferably comprises borneol and an organic acid activator that volatilizes during soldering. The flux is applied as a solution of borneol and the organic acid activator in a solvent that substantially evaporates before soldering without leaving any measurable solvent residue.

Abstract: A polymer-based solder paste composition having the strength and corrosion resistance of joints produced by conventional solder technology and the environmental and processing advantages of ICA technology comprises a powdered solder metal with a single component (single package) polymerizable flux composition. In one embodiment the polymerizable flux composition includes 55-70% by weight of an epoxy such as epoxy novolac, the diglycidyl ethers of bisphenol A and F, and mixtures thereof, 0-15% by weight of a dicarboxylic acid, 3-5% by weight of an amine thermal curing agent, and the balance may include a polyalcohol, a chelating agent, a defoamer, a thixotrope and a surfactant. In another embodiment the polymerizable flux composition includes approximately 55-70% by weight of an epoxy such as trifunctional epoxide of p-aminophenol, approximately 20-30% by weight of a liquid organic acid such as a carboxy-acrylate, and approximately 4-10% by weight of an amine thermal curing agent.

Abstract: A thermally curable adhesive composition that includes a fluxing agent that also acts as an adhesive is provided. The composition includes: (a) a fluxing agent represented by the formula RCOOH, wherein R comprises a moiety having two or more carbon-carbon double bonds wherein in one embodiment, at least one is within an acrylate or methacrylate group, and which may further contain at least one aromatic moiety; (b) optionally, an effective amount of a crosslinkable diluent; (c) optionally, an effective amount of a source of free radical initiators; and (d) optionally, an effective amount of a resin to react with remnant carboxylic acid moieties. By employing an acrylate, methacrylate, or phenol in the structure of the adhesive flux, the cure temperature and moisture absorption characteristics can be significantly improved. The composition can be applied directly onto the surface(s) of devices that are to be joined electrically and mechanically.

Abstract: A thermally curable adhesive composition that includes a fluxing agent that also acts as an adhesive is provided. The composition includes: (a) a fluxing agent represented by the formula RCOOH, wherein R comprises a moiety having two or more carbon--carbon double bonds; (b) optionally, an effective amount of a crosslinkable diluent; (c) optionally, an effective amount of a source of free radical initiators; and (d) optionally, an effective amount of a resin to react with remnant carboxylic acid moieties. The composition can be applied directly onto the surface(s) of devices that are to be joined electrically and mechanically. These devices include, printed circuit substrates, connectors, components, cables, and other electrical devices having metallization patterns to be soldered together by means of a solder-bumped pattern on one or both surfaces. Alternatively, a solder paste, comprising solder powder mixed with the fluxing agent of the present invention can be used.

Abstract: A flux which contains irreversibly dehydrated K.sub.2 AlF.sub.5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Abstract: A flux composition for use together with solder preforms, which comprises rosin, N-unsubstituted or N-substituted 2-pyrrolidone, and optionally a high boiling point ester solvent with a content of N-unsubstituted or N-substituted 2-pyrrolidone being 3-50% by weight and a content of the ester solvent being not greater than 30% by weight.

Abstract: Provided are a soldering flux or paste containing an organic substance which has at least two hydroxyl (--OH) groups in a molecule and of which the temperature at which the mass % becomes approximately 0% is not lower than approximately 170.degree. C. and not lower than the solid phase linear temperature of the solder, as measured by thermal gravimetry in which a flow rate of an air or nitrogen (N.sub.2) gas atmosphere is 200 ml/min and a rate of temperature rise is 10.degree. C./min, and a soldering method using the same. The soldering flux or paste of the present invention gives good wettability to a matrix to be bonded in a normal temperature profile and in a non-reductive atmosphere without leaving any residue.

Abstract: A resin-based VOC-free soldering flux consists of 40 to 50 wt % of a liquid epoxy resin, 25 to 30 wt % of a non-volatile liquid epoxy diluent, 20 to 33 wt % of a polyfunctional carboxylic acid, and 2.0 to 3.5 wt % of a thixotropic agent. There are no volatile organic solvents or compounds in the flux which can evaporate during the reflow process. The carboxylic acids are provided in powdered form and are suspended in the epoxy blend wherein they remain as solid particles until heated in the solder reflow process. A VOC-free solder paste formed from the flux consists of 40 to 95 wt % soldering particles, and 5 to 60 wt % of the VOC-free soldering flux. The thixotropic agent improves printability of the solder paste onto printed wiring boards. A VOC-free flux-core solder wire includes the VOC-free flux as the inner core of the wire with an outer shell of solder alloy.

Abstract: The invention provides a soldering flux for mounting circuit substrates, which is free from any organic solvent attributable to air pollution and dispenses with any washing step. The soldering flux is obtained by dissolving a rosin modified by an unsaturated organic acid according to the Diels-Alder reaction in an aqueous solvent. A volatile basic agent may further be contained in the flux.

Abstract: A polymer-based solder paste composition having the strength and corrosion resistance of joints produced by conventional solder technology and the environmental and processing advantages of ICA technology comprises a powdered solder metal with a single component (single package) polymerizable flux composition. The polymerizable flux composition includes 55%-65% by weight of an epoxy such as epoxy novolac, the diglycidyl ethers of bisphenol A and F, and mixtures thereof, 0-15% by weight of a dicarboxylic acid, 9%-11% by weight of a polyalcohol, 3%-5% by weight of an amine thermal curing agent, and the balance including a chelating agent, a defoamer, a thixotrope and a surfactant. Upon heating, the solder metal spontaneously segregates from the flux composition, fuses, and forms a metallurgical joint, while the single-component polymerizable flux composition encapsulates the fused metal in a polymer coating which remains firm but pliable at reflow temperatures.

Abstract: A mixture of a dye including one or more water soluble fluorescent dyes and a water soluble solder flux provides simple optical inspection under ultraviolet illumination with simple apparatus. The optical inspection is thus made highly sensitive to the presence of residual water soluble flux after washing and highly specific to the water soluble flux with which the dye is mixed. Thus, optical inspection can assure that all water soluble flux is removed to avoid subsequent corrosion while providing the possibility of leaving so-called "no clean" fluxes in place.

Abstract: A flux for soft soldering is disclosed. It comprises a chelating agent as an activator for facilitating a connection of a conductor metal to a soft solder by removing an oxide film naturally formed on the surface of the conductor metal, and for securing insulating reliability after soft soldering by forming complexes with copper and tin which are insulating substance, and a solvent capable of dissolving the chelating agent and further preferably evaporating at soldering process.

Abstract: A new flux composition, as well as corresponding methods for soldering electronic components to printed circuit boards, is disclosed. The new flux composition includes pimelic acid and two organic solvents. Significantly, the new flux composition leaves essentially no ionic residues at the completion of the soldering processes used to mount electronic components onto printed circuit boards.

Abstract: The present invention relates to a method for mounting electronic devices on a substrate by using soldering with flux which contains materials capable of ion-exchanging or ion-catching so as to catch impurity ions which seep from a solder portions, and thereby it is not necessary to have a fusing step and a cleaning step in an plating process of the method.

Abstract: A flux-free method for bonding a member which is at least partially metallic to another member is provided including preserving the at least partially metallic member in a container having a low gas permeability, together with a packet containing a rust-proof composition; and bonding the at least partially metallic member with the other member by using a filler material.

Abstract: A flux formulation for use in the assembly of electronic circuit boards having components to be joined by soldering. The formulation comprises a medium which acts as a carrier and solvent for the fluxing agent, which includes in a preferred embodiment supercritical carbon dioxide. The formulation also includes a fluxing agent, being at least partially soluble in the supercritical carbon dioxide which serves to transport the fluxing agent before deposition thereof upon a soldering site. The supercritical fluid is delivered through a nozzle to the circuit board, the supercritical condition being maintained until the supercritical fluid is discharged from the nozzle. The fluxing agent at least partially loses its solubility in the fluid thereupon and is transported to the board by a stream of carbon dioxide gas. Also disclosed is a method for delivering a flux formulation to the electronic circuit board.

Abstract: Flux for soldering comprising inorganic ion-exchanger and activator containing halogen atom, solder composition the flux and solder particles, soldering method comprising coating the solder composition on a portion for soldering, soldering method comprising coating flux containing activator on a portion for soldering, applying inorganic ion-exchanger to the portion and applying solder to the portion, and soldering method comprising mixing inorganic ion-exchanger with creamy solder to give mixture, coating the mixture on a circuit pattern of a wiring plate and heating the wiring plate. The flux for soldering and the soldering composition are excellent in metal ion-migration resistance, corrosion resistance, soldering property and storage stability, and can be preferably used without cleaning and the soldering methods can be preferably used in practical no-clean soldering methods.

Abstract: A braze filler metal alloy paste containing braze metal alloy powders, such as a nickel- or cobalt-based braze filler metal, homogeneously dispersed throughout an aqueous gel solution comprising a binder such as a cellulose material, for example, sodium carboxymethyl-cellulose and a dispersants such as mineral oil and glycerine.

Abstract: A no-VOC or low-VOC no-clean flux formulation for use in the assembly of electronic circuit boards having a conformal coating. The formulation comprises a solvent, a water-soluble weak organic acid, a halide-free, non-ionic surfactant, and a biocidal co-solvent. The formulation is compatible with the conformal coating, permits no or low VOC emissions into the environment, and eliminates post-soldering cleaning steps.

Abstract: To produce an active brazing paste suitable for brazing leads in insulating parts, e.g., ceramic parts, and containing an active brazing powder and an organic material acting as a vehicle, coarse pieces of the active brazing alloy are prehydrogenated. These pieces are ground in a mill with the addition of hydrogen to form a hydrogenated active brazing powder. The latter is then processed with the liquid vehicle openly, under normal atmospheric and temperature conditions, to form the active brazing paste.

Abstract: A composition of matter useful particularly as a desoldering flux is disclosed. In some embodiments the invention combines a "low solids" flux normally provided for automatic wave and other soldering equipment with additional naturally-occurring rosin to create a composition capable of use with copper desoldering braid and manual desoldering operations.

Abstract: Electrically conductive adhesive compositions and methods for the preparation and use thereof, in which a solder powder, a chemically protected cross-linking agent with fluxing properties and a reactive monomer or polymer are the principal components. Depending upon the intended end use, the compositions comprise three or more of the following: a relatively high melting metal powder; solder powder; the active cross-linking agent which also serves as a fluxing agent; a resin; and a reactive monomer or polymer. The compositions are useful as improved conductive adhesives, such as for attaching electrical components to electrical circuits: the compositions comprising metal powder are ideally suited for creating the conductive paths on printed circuits. The compositions for forming conductive paths may first be applied to a substrate in the desired pattern of an electrical circuit, and then heated to cure it.

Abstract: Soldering flux and solder paste compositions which are non-acidic, low-residue, and non-corrosive, leaving no substantial residue after soldering without a subsequent cleaning process and yet exhibiting excellent solderability are disclosed. The compositions comprise (A) at least one compound which generates a peroxide by decomposition or oxidation when subjected to heating, and (B) at least one ester from an inorganic or organic acid which generates an acid by decomposition in the presence of compound (A). They are particularly advantageous for eliminating the cleaning process with a solvent such as Flon to solve the ozone layer destruction problem and for improving the performance of the in-circuit test for printed-circuit boards after soldering.

Abstract: A no-clean, low-residue, rosin-free foam flux solution is described which comprises a cosolvent system free of volatile organic compound solvents which is comprised of (i) at least about 90% by weight demineralized water based on total weight of the flux solution and (ii) from about 1% by weight to about 5% by weight based on total weight of the flux solution of a non-volatile organic solvent forming a cosolvent with said demineralized water, said nonvolatile organic solvent having a boiling point above about 190.degree. C. and a vapor pressure below 0.1 millimeters Hg at 25.degree. C.; a fluxing agent present in an amount from about 1% to about 4% by weight based on total weight of the soldering flux, said fluxing agent comprising at least two carboxylic acids selected from the group consisting of C.sub.2 -C.sub.

Abstract: Solder powders coated with a thin layer of parylene and solder pastes containing the coated solder powders are disclosed. The coated solder powders can exhibit a high degree of resistance to oxidation and to reaction with the flux contained in the solder paste without substantially interfering with the reflow characteristics of the solder.

Abstract: The solder bonding is conducted by applying a postflux, which contains halogen compounds in the ratio of 0.2% or less as the amount of halogen, over a metal surface, which is the portion to be bonded by solder, of a member including metal accommodated in a gas-impermeable container in a hermetically sealed manner together with a rust-proof agent packet. The method of the present invention prevents, in an extremely simple way and at a low cost, the oxidation of the metal surface by retaining the member including the metal under a reductive atmosphere in which no oxygen, moisture or corrosive substances actually exist, and in which reductive gas co-exists with the material including the metal member, and the use of the flux containing a small amount of halogen easily enables good bonding properties of the solder. Accordingly, it is unnecessary to remove the flux by organic halogen based solvents after the solder bonding, the cleaning steps may be simplified and cost reduction may be promoted.

Abstract: A no-clean soldering flux consists essentially of one or more halide-free, water soluble activators in an aggregate amount not exceeding about 5% by weight of the flux, a water soluble fluorinated surfactant in an amount not exceeding about 1% by weight of the flux, and water. The flux is substantially VOC-free and is particularly useful in a method of producing soldered printed wiring assemblies with minimal residual ionic contamination, so that post-soldering cleaning of the assemblies is unnecessary. The absence of significant amounts of VOC's and the elimination of post-soldering cleaning result in substantial environmental and production-related benefits.

Abstract: A fluxing composition for soldering metals together, contains a carrier solvent, an oxide removing agent, and a nitrogen liberating compound. The oxide removing agent sublimes at or below the temperature at which the metals are soldered together. The nitrogen liberating compound sublimes or decomposes at below the temperature at which the metals are soldered together in order to provide a blanket of inert gas over the metals being soldered. The oxide removing agent is 2-amino-isophthalic acid, 5-amino-isophthalic acid, isophthalic acid, ammonium fluoborate, or ammonium salicylate. The compound that liberates nitrogen upon heating is 1,2-benz-3,4-anthraquinone, 1,2-benz-9,10-anthraquinone, 5,6-chrysoquinone, 6,12-chrysoquinone, 2,3-benzanthraquinone, 2-amino-isophthalic acid, 5-amino-isophthalic acid, or 5-isoquinoline carboxylonitrile. Electronic components are soldered to a circuit board by applying the fluxing composition to the circuit board.

Abstract: A flux for use in a dry process for the flux treatment of the material to be coated with molten metal contains at least one chloride selected from the group consisting of zinc chloride, stannous chloride, an alkali metal chloride and an alkaline earth metal chloride and at least one aliphatic nitrogen derivative with alkyl group having 1 to 18 carbons. The treatment of steel with this flux enables the formation of a coating having a good finish from, among others, a molten alloy of zinc and aluminum, which may further contain other elements, or molten aluminum, by a single dipping operation in an atmospheric environment which has hitherto been difficult. A process for manufacturing steel coated with molten metal, including its treatment with the flux, is also disclosed.

Abstract: A no-clean, low-residue, rosin-free soldering flux is described which comprises a solvent consisting essentially of demineralized water present in amount of at least about 95% by weight based on total weight of the soldering flux; from about 1% to about 4% by weight based on total weight of the soldering flux of a fluxing agent consisting essentially of at least two carboxylic acids selected from the group consisting of C.sub.2 -C.sub.10 dicarboxylic acids, monocarboxylic acids and hydroxy acids, said fluxing agent being present as solute in said deionized water solvent; and nonionic surfactant present in an amount of less than about 1% by weight based on total weight of soldering flux.

Abstract: A soldering paste for light beam-heating soldering containing a flux which contains 2 to 8 % by weight of a thixotropic agent having a melting point of 140.degree. to 150.degree. C., 1.8 to 3.0 % by weight of an activator containing cyclohexylamine hydrobromide, 40 to 50 % by weight of a rosin component and 40 to 50 % by weight of a solvent; and spherical solder particles having a particle size of 250 to 400 mesh and an oxygen content of not larger than 200 ppm, in which a content of the flux in the soldering paste is from 9 to 13 % by weight and the soldering paste has a thixotropy index of 7 to 8.

Abstract: In a paste for use in the electronics industry which comprises:i) a non aqueous vehicle; andii) a particulate filler material, the improvement which comprises the vehicle being a stable emulsion of at least two immiscible organic liquids of at least 50% by volume disperse phase, one of which liquids is selected from the group consisting of a polar solvent and a mixture of polar solvents, and the other of which liquids is selected from the group consisting of an aliphatic hydrocarbon and a mixture of aliphatic hydrocarbons and the paste, when heated to remove the vehicle therefrom yields less than 3.0% by weight of organic residues based on the weight of the paste.

Abstract: Disclosed is a water-soluble solder flux and a method of fabricating circuit boards which does not adversely affect the insulation resistance of the boards. The flux applied to the board comprises a vehicle including at least two random copolymers of polyalkylene glycol with various amounts of ethylene oxide and propylene oxide. The flux also exhibits a low viscosity for improved copper coverage.

Abstract: A solder paste that is useful in applications such as surface mounting of components on printed circuit boards has been found. After soldering, the residue requires no cleaning. The achievement of these desirable properties is accomplished by employing a solder flux vehicle including a three component residue modifier.

Abstract: A soldering flux composition comprising, as a flux base resin, a modified amine compound obtained by reacting (i) at least one member selected from the group consisting of vinyl group-containing compounds, carboxyl group-containing compounds and epoxy group-containing compounds (ii) with an amine compound having an active hydrogen.

Abstract: A non-toxic, non-corrosive foaming soldering flux (14) comprises citric acid and water, together with at least one foaming agent. The foam is fast-breaking, dissipating almost immediately. Such a fast-breaking foam is novel in an aqueous-based flux. The unique flux of the invention produces solder joints of high metallic luster and excellent quality. Disposal presents no health hazards, and clean-up of flux residues is accomplished using only water and, optionally, a surfactant.

Abstract: A water soluble, thermally stable, solder flux for use in forming a water soluble, thermally stable, solder paste is provided. The water soluble, thermally stable, solder flux contains an acidic ester component having about 50% to about 60% monoesters by weight based on total weight, about 40% to about 50% diesters by weight based on total weight, and about 0% to about 1.5% phosphoric acid by weight based on total weight. This ester component is combined with triethanolamine to form a flux vehicle having a molar ratio of triethanolamine to the ester component of about 0.6 to about 1.2. This vehicle is present in the solder flux in an amount from about 68% to about 79% by weight based on total weight of solder flux. The flux also contains rheology adjusting components in an amount ranging from about 17% to about 26% by weight based on total weight of solder flux. Citric acid included in the flux in an amount ranging from about 4% to about 6% by weight based on total weight of solder flux.

Abstract: A paste solder with minimized flux residue remaining after soldering comprises a powdered solder and a flux in admixture. The flux comprises from about 5% to about 40% by weight of carrier components which comprise a rosin or a rosin derivative, an activating agent, and a thixotropic agent and from about 60% to about 95% by weight of a solvent which predominantly comprises a 2-alkyl-1,3-hexanediol having 1 to 4 carbon atoms in the alkyl group.

Abstract: Discloses an aluminium brazing paste which not only has excellent preservability and coating performance but also reveals excellent brazing characteristics; said aluminium brazing paste according to this invention comprises, per 100 parts by weight of aluminum-containing metal powder with 10 to 500 .mu.m of mean particle size for aluminium brazing, of 0.5 to 15 parts by weight of flux and 30 to 80 parts by weight of a liquid polyisobutylene with 300 to 1500 of average molecular weight and/or its hydrogenated product.

Abstract: Disclosed is a soldering flux which prevents a release of an active ion contained in an activator when exposed to a high-temperature atmosphere maintaining at a temperature higher than 80.degree. C., for example, an atmosphere of an engine room of an automobile, and thus makes washing unnecessary. This soldering flux comprises, together with an activator, (1) a thermoplastic resin having a softening point not lower than 80.degree. C., and/or (2) an epoxy group-containing compound, a radical-polymerizable unsaturated double bond-containing compound or a blocked isocyanate group-containing compound, or (3) a thermosetting resin composed of a carboxyl group-containing resin and an epoxy resin and/or a thermosetting resin containing carboxy and epoxy groups.

Abstract: A solder flux that is useful in applications such as surface mounting of components on printed circuit boards has been found. After soldering, the residue from the flux is either removable by water cleaning or requires no cleaning at all. The achievement of these desirable properties is accomplished by employing a solder flux vehicle including a removing agent, a low vapor pressure component, a high temperature component, and a rheological properties promoter.

Abstract: A method and composition for protecting and enhancing the solderability of a metallic surface. A mixture which includes a chosen protective material and a dicarboxylic acid fluxing agent is applied to the metallic surface to form a protective film or coating which also enhances the solderability of the metallic surface. The mixture is applied to the metallic surface as a solution having a solvent carrier which evaporates to leave the film. the film is heat activated at soldering temperatures to release the fluxing agent.

Abstract: A non-toxic, non-corrosive water-soluble soldering paste comprises at least about 80 wt % of particulate solder and the balance a thixotropic flux base. The flux base has a viscosity of at least about 200,000 cp and comprises (a) a botanical oil, (b) an aqueous emulsion of a thickening agent, such as corn starch or an ethoxylated linear alcohol in water, and (c) an organic acid having at least two carboxylic acid groups, such as citric acid. The paste of the invention produces solder joints of high metallic luster and excellent quality. Clean-up of paste residues is ac complished using only water.

Abstract: An adhesive material 220 including a fluxing agent and metal particles 240 is applied to either a substrate 200 having a metallization pattern 210 or an electrical component 230. The component 230 is positioned on the substrate 210 and heated. During the heating step, the fluxing agent promotes adhesion of the metal particles 240 to the substrate metallization pattern 210 and the component, and the adhesive material 220 is cured, to mechanically interconnect and encapsulate the substrate 210 and the component 230.

Abstract: A soldering flux includes at least one acid component and at least one ester component. The acid component is selected from among dibasic carboxylic acid, hydroxycarboxylic acid and keto carboxylic acid. The ester component is selected from among phosphoric ester, phosphorous ester and hypophosphite ester.

Abstract: A no-clean, thermally dissipated soldering flux is shown which includes hydroabietal alcohol as a flux base, an organic activator and an organic diluent. The hydroabietal alcohol provides a tacky medium which holds a precisely aligned chip in place both during placement and reflow. The nature of the formula renders a reducing atmosphere unnecessary. The composition is thermally dissipated during soldering and leaves no undesirable residue which would require a post-cleaning step.

Abstract: Water soluble soldering preflux compositions are shown which include gum arabic, modified polysaccharides and other natural resins as a carrier, an oxidation inhibitor and water. The compositions are useful in the assembly of precisely aligned electrical components during multiple step, electronic card assembly techniques. Use of the preflux compositions according to the method of the invention permits a flexible, site-specific method for joining electronic components to a printed circuit board with a fewer number of steps.

Abstract: Solder pastes having vehicles including formic acid-soluble organic acids as fluxing agents are described. Fluxing agents may be compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, acrylic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize leaving a residue to be cleaned away. The cleaning step involves rinsing with formic acid. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards.