Abstract: The present invention relates to aqueous dispersions comprising multistage-prepared polymers of olefinically unsaturated compounds and to the preparation and use thereof, in particular in the field of automobile coating.

Abstract: An automated analyzer for reagent cards having a leading end, a trailing end and a length between the leading end and the trailing end comprises a travel surface assembly having a card travel surface and an edge. A test analyzing mechanism is adjacent to the travel surface, and a waste receptacle is adjacent to the edge below the travel surface. The waste receptacle has a side and a waste cavity. A ramp member positioned below the travel surface has an end and a sloped surface, and is movable between an extended position where the sloped surface extends into the waste cavity, and a retracted position where the end is spaced from the side a distance greater than the length of the reagent card. A moving mechanism operably coupled with the ramp member is configured to move the ramp member between the extended position and the retracted position.

Abstract: A more efficient process of sealing an anodized aluminum article, which can facilitate higher production rates than conventional sealing techniques, includes steps of providing an article comprised of aluminum or an aluminum alloy that has been anodized, treating the oxide layer with a solution containing an anion capable of combining with a cation to form a water-insoluble precipitate, and contacting the treated oxide layer with a second solution containing a cation which combines with the anion to form a water-insoluble precipitate. In certain embodiments, the oxide layer can be treated with a dye to provide a sealed anodized aluminum article exhibiting enhanced dye retention.

Abstract: A flexible substrate has heat resistance to endure the high temperature such as sintering of a photovoltaic conversion layer of a compound-type thin film solar cell, can prevent permeation and/or diffusion of metal into the photovoltaic conversion layer, and can be used for many applications. The polyimide layer-containing flexible substrate has a metal substrate of metal foil made of ordinary steel or stainless steel having a coefficient of thermal expansion in a plane direction of not more than 15 ppm/K, or a metal substrate of metal foil made of that ordinary steel or stainless steel on the surface of which a metal layer comprising one of copper, nickel, zinc, or aluminum or an alloy layer of the same is provided, over which a polyimide layer having a layer thickness of 1.5 to 100 ?m and a glass transition point temperature of 300 to 450° C. is formed.

Abstract: A single-liquid type paint composition comprises: a hydroxyl group-containing polyester resin (A) of which the weight average molecular weight is from 1,500 to 8,000, the acid value is from 0 to 50 mgKOH/g, the hydroxyl group value is from 100 to 180 mgKOH/g and the glass transition temperature is from ?30 to 0° C. and a crosslinking agent (B) which reacts with hydroxyl groups, wherein the (A) component has been obtained by reacting a polybasic acid (a), a polyhydric alcohol (b) and at least one type of component (c) having at least six carbon atoms selected from among the saturated mono-carboxylic acids, saturated mono-alcohols, saturated glycidyl ethers and saturated glycidyl esters where the proportion by mass of the (c) component is from 20 to 60 mass % with respect to the sum of the solid fraction masses of the (a) to (c) components.

Abstract: An article has a polymeric substrate and a coating system. The coating system includes a metallic plating and a polymeric coating atop the metallic plating. The metallic plating has a thickness of at least 0.05 mm.

Abstract: Embodiments may generally take the form of systems and techniques for reducing or eliminating crazing in anodized metal. In particular, one embodiment may take the form of a method for sealing an anodized metal member including placing the anodized metal member in a sealing bath having water. The sealing bath initially has a first temperature that is less than a sealing temperature. The method also includes continuously heating the sealing bath to the sealing temperature, maintaining the bath at the sealing temperature for a period of time, and removing the anodized metal member from the sealing bath after the period of time has lapsed.

Abstract: The invention relates to a process for the preparation of a multi-layer coating film on an electrically conductive substrate, comprising the steps of electrodepositing on an electrically conductive substrate, a first coating composition to form an uncured electrodeposition coating film, applying an aqueous primer-surfacer coating composition to form an uncured intermediate coating film, and then simultaneously heating the substrate coated with the said coating films and curing both the uncured electrodeposition coating film and the uncured intermediate coating film to form a cured film, wherein the curing agent B is a capped isocyanate where the capping agents are selected from the group consisting of aliphatic linear or branched diols, hydroxyalkyl(meth)acrylates and >NH functional heterocyclic aliphatic or aromatic compounds, to coating films made by this process, and to substrates covered with such coating films.

Abstract: A manufacturing method for steel sheets for containers produces steel sheets with excellent film adhesion qualities. This steel sheet for containers has, on a steel sheet, a chemical conversion coating with a metal Zr content of 1-100 mg/m2, a P content of 0.1-50 mg/m2, and an F content of no more than 0.1 mg/m2, upon which is formed a phenolic resin layer with a C content of 0.1-50 mg/m2. Moreover, the manufacturing method for steel sheets for containers is a method for obtaining the steel sheet for containers wherein the chemical conversion coating is formed on the steel sheet by subjecting the steel sheet to immersion in or electrolytic treatment with a treatment solution containing Zr ions, phosphoric acid ions, and F ions; and subsequently, the steel sheet upon which the chemical conversion coating has been formed is immersed in, or undergoes topical application of, an aqueous solution containing phenolic resin, then dried.

Abstract: The presently disclosed embodiments are directed to an improved metallization process for making fuser members which avoids the extra steps of metal nanoparticle seeding or special substrate treatment. In embodiments, a metallized substrate, formed by dip-coating or spraying with a metal nanoparticle dispersion which is subsequently thermally annealed, is used for the complete fabrication of the fuser member.

Abstract: There is described an open cell porous structure the cells of which are optionally filled with an elastomeric or thermosetting plastic comprising a nanocrystalline metallic or nanocrystalline metal matrix composite coating wherein the nanocrystals have a crystallite size of from about 5 nm to about 150 nm. A process for preparing the coated open cell porous structures is also disclosed.

Abstract: The presently disclosed embodiments are directed to an improved metallization process for making fuser members which avoids the extra steps of metal seeding or special substrate treatment. In embodiments, a metallized substrate, formed via a polycatecholamine-assisted metallization process, is used for the complete fabrication of the fuser member.

Abstract: The invention relates to a biosensor comprising an electrically conductive substrate, with a first layer comprising Ruthenium Purple formed on the substrate, a second layer comprising polyaniline or a derivative thereof comprising one or more non-polar substituents formed on the first layer, and a third layer comprising one or more enzymes trapped within a matrix formed on the second layer. The biosensor is for use in the detection of analytes such as purines and derivatives thereof, particularly in the detection of hypoxanthine.

Abstract: A composite membrane assembly is provided. The composite membrane assembly comprises a porous substrate, a filtering membrane at least partially coupled to the porous substrate, a polymer membrane at least partially coupled to the filtering membrane, and an interface material at least partially disposed between the filtering membrane and the polymer membrane.

Abstract: The present invention relates to an electrode useful in electrochemical nanobiosensors for determining the presence or concentration of analytes in aqueous samples. In particular, the electrode comprises a biocatalyst or other bioreceptor entrapped in a conducting polymeric film deposited on a conducting material and a non-conducting or conducting coating. In particular embodiments, the conducting polymeric layer also comprises metallic nanoparticles. Electrochemical nanobiosensors containing the electrode, methods of making the electrode or sensor and methods of detecting analytes are other aspects of the invention.

Abstract: This invention provides water-based paint compositions containing water-dispersible acrylic polymer particles, hydroxyl-containing resin and curing agent, the water-dispersible acrylic polymer particles having a weight-average molecular weight of at least 1,100,000 and an absorbance value not higher than 0.2 at a wavelength of 330 nm, as measured with spectrophotometer in the state of liquid dispersion at a mass concentration of 1.35% in 1,4-dioxane solvent; and the compositions excelling in finished appearance such as coated surface smoothness and coating film performance such as chipping resistance and water resistance.

Abstract: The invention relates to a corrosion-protective layer for protecting steel substrates from corrosion, comprising a zinc-chromium layer applied on the steel substrate by electrolytic joint deposition of zinc and chromium ions, and a chromate-free organic thin layer applied thereon, substantially comprising synthetic resins, and to a method for improving the paint adhesion of a zinc-chromium corrosion-protective layer.

Abstract: The disclosure relates to porous silicon/conductive polymer composites that can be used in biosensor applications (e.g., in a binding assay that captures a target analyte). The composite material generally includes (a) a p-doped silicon substrate that has a porous surface; (b) a lawn of a conductive polymer bound to the porous surface; and (c) a binding pair member bound to the conductive polymer. The porous silicon surface provides excellent adhesion between the substrate and the conductive polymer, thereby eliminating the need for an intervening metallic layer. Processes according to the disclosure for forming the composite material generally include electropolymerizing and electrodepositing the conductive polymer onto the porous surface of the silicon substrate and then binding the binding pair member to the conductive polymer. Methods and kits employing the composite materials are also disclosed.

Abstract: A process for forming a multilayer composite coating on a substrate is provided. The process includes forming an electrodeposition coating layer on the substrate by electrodeposition of a curable electrodepositable coating composition over at least a portion of the substrate. Optionally, the coated substrate is heated to a temperature and for a time sufficient to cure the electrodeposition coating layer. A basecoating layer is formed on the electrodeposition coating layer by depositing an aqueous curable basecoating composition directly onto at least a portion of the electrodeposition coating layer. Optionally, the basecoating layer is dehydrated. A top coating layer is formed on the basecoating layer by depositing a curable top coating composition which is substantially pigment-free directly onto at least a portion of the basecoating layer. The top coating layer, the basecoating layer, and, optionally, the electrodeposition coating layer are cured simultaneously.

Abstract: A structure and a method of preventing electrolytic corrosion for a magnesium alloy member (20), the structure wherein a first coated layer (11) formed by electro deposition and a second coated layer (12) formed by distributing PTFE particles on the first coated layer (11) are covered on the surface of a tightening member (1) at least on a surface coming into contact with the magnesium alloy member (20), whereby, the electrolytic corrosion of the magnesium alloy member can be prevented at a low cost by insulating a tightening member such as a steel bolt and a washer from the magnesium alloy member, and an adhesiveness therebetween can be sufficiently assured.

Abstract: A process is provided for making a composite work article suitable for fabricating rigid sheet metal can components. A steel sheet having first and second surfaces is pre-treated to enhance reception and retention of a multi-layer polymer coating on the pre-treated first surface. The multi-layer polymer coating is melt extruded on the pre-treated first surface and beyond opposite lateral edges of the work article to establish overhang portions, then solidified. The multi-layer polymeric coating has a tie polymeric layer contacting the pre-treated first surface, and a finish-surface polymeric layer.

Abstract: The present invention provides a black, chrome-free, multilayer corrosion protection finish designed to meet extended corrosion properties. This corrosion-resistant finish is engineered to meet a minimum of 500 salt spray testing hours to white corrosion, and 1500 salt spray testing hours to red corrosion when tested to ASTM B117 standards. It is also designed to comply with the European Union Directive on End of Life Vehicles. This multilayer system is designed for use on automotive body sheet steel, automotive underbody parts, automotive under-hood parts, and some automotive interior parts specifying a gloss requirement greater than 4. This chrome-free, multilayer finish is a combination of a zinc-iron electroplated substrate, a non-electrolytic phosphate crystal conversion layer using orthophosphoric acid, and a Xylan/Teflon fluorocarbon sealer coating to form a three layer total corrosion protection system.

Abstract: An article coated with an electrolytically deposited bio-compatible composite layer useful as an internal prosthetic device is disclosed. The bio-compatible composite coating that is electrolytically deposited onto the article comprises hydroxyapatite and chitosan. The introduction of chitosan into the crystal matrix of brushite/hydroxyapatite significantly improves the adhesive and chemical and mechanical stability properties of the coating.

Abstract: A two-layered anode (1?) has a lower layer (2) including a non-conductive carrier material to which a conductive electrode layer (3?) is applied. Non-conductive areas, formed by partial removal of the electrode layer, have a predetermined structure corresponding to the structure of a structured polymer film (11) to be formed. The anode (1?) is connected with a platinum cathode in an electrolyte into which compounds of low molecular weight, preferably monomers of the polymer film (11), are introduced. During current flow, a conductive polymer film (11) of the predetermined structure is formed on conductive areas brought into contact with the electrolyte. A non-conductive substrate layer (13) is applied to the structured polymer film (11). The structured polymer film (11) adheres to the non-conductive substrate layer (13) and can be released from the electrode (1?) without damaging the electrode.

Abstract: A method for enhancing the solderability of a metallic surface is disclosed where the metallic surface is plated with an immersion silver plate prior to soldering, which immersion silver plate is treated with an additive selected from the group consisting of fatty amines, fatty amides, quaternary salts, amphateric salts, resinous amines, resinous amides, fatty acids, resinous acids, ethoxylated derivatives of any of the foregoing, and mixtures of any of the foregoing. The immersion silver deposits created are resistant to electromigration.

Abstract: The quality of painted surfaces of polymeric articles is improved by depositing a coating of a metal such as zinc or zinc alloy on the surface of the article to be painted. For example, zinc is electrodeposited on a conductive surface of the article. The metal coated polymeric surface provides a good base for electrostatic deposition of either liquid or powder paint and the metal surface prevents the formation of defects in the painted surface during heating of the article to dry or cure the paint film.

Abstract: The quality of painted surfaces of polymer composites is improved by first forming an electroless metal coating on the molded surface of the composite and then electroplating a coating of zinc or zinc alloy on the metallized composite surface. The “galvanized” composite surface provides a good base for electrostatic deposition of either liquid or powder paint and the zinc surface prevents the formation of defects in the painted surface during heating of the composite to dry or cure the paint film.

Abstract: The present invention provides a palladium plating solution comprising at least 1 to 60 g/L, in terms of the amount of palladium, of a soluble palladium salt and 0.1 to 300 g/L of a sulfamic acid or its salt, the palladium plating solution being substantially free from a brightening agent. This plating solution can be used to form, on a substrate, a palladium plating having on its surface an acicular crystal, and, thus, a plating having excellent adhesion to resin can be provided on the surface of a substrate.

Abstract: This invention employs a novel approach to the copper metallization of a workpiece, such as a semiconductor workpiece. In accordance with the invention, an alkaline electrolytic copper bath is used to electroplate copper onto a seed layer, electroplate copper directly onto a barrier layer material, or enhance an ultra-thin copper seed layer which has been deposited on the barrier layer using a deposition process such as PVD. The resulting copper layer provides an excellent conformal copper coating that fills trenches, vias, and other microstructures in the workpiece. When used for seed layer enhancement, the resulting copper seed layer provide an excellent conformal copper coating that allows the microstructures to be filled with a copper layer having good uniformity using electrochemical deposition techniques. Further, copper layers that are electroplated in the disclosed manner exhibit low sheet resistance and are readily annealed at low temperatures.

Abstract: A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

Abstract: The present invention is a process for manufacturing resistors integral with the printed circuit board by plating the resistors onto the insulative substrate. The invention uses a mask during the activation step so as to selectively activate only selected portions of the surface thus enabling smaller areas to be plated on the printed circuit board because no plating mask is used. The process of the instant invention produced printed circuit boards having greater uniformity and reliability as compared to the prior art.

Abstract: The present invention provides a water-based intermediate coating composition having excellent chipping resistance and water resistance when made into a multilayer coating film, and providing excellent adaptability with a top coating film and a base coating film and excellent finish appearance, and a method for forming a multilayer coating film using the same.

Abstract: A method of plating for filling via holes, in which each via hole is formed in an insulation layer covering a substrate so as to expose, at its bottom, part of a conductor layer located on the substrate. A copper film is formed on the top surface of the insulation layer covering the substrate, and the side walls and bottoms of the respective via holes. A strike plating of copper is provided on the copper film, and the substrate is immersed in an aqueous solution containing a plating promoter to thereby deposit the plating promoter on the surface of the copper strike. The plating promoter is removed from the copper strike plating located on the top surface insulation layer while leaving the plating promoter on the side walls and bottoms of the respective via holes. The substrate is subsequently electroplated with copper to fill the via holes.

Abstract: A method for coating zinc, zinc plated, or steel articles with a hydroxy benzoic acid protective coating by coating a cleaned zinc, zinc plated, or steel with a hydoxy benzoic acid composition having a pH of about 2.0 to 5.0; and coating cleaned tin surfaced articles with a composition having a PH of 2.0 to 12.0, and the composition having as its essential ingredients proteins, amino acids, amino acid—protein compounds and amine alcohols; and the articles produced thereby along with the coated articles having an appropriate paint thereon.

Abstract: Corrosion resistance of metallic components such as stainless steel components of vehicles, and especially aluminum-based components of aircraft, is enhanced by application of an e-coat paint or primer which is enhanced by incorporation of cerium ions into the e-coat electrolytic bath. The resulting overall coating includes a cerium-based layer under a cerium-enhanced e-coat paint or primer layer.

Abstract: A method for enhancing the solderability of a metallic surface is disclosed where the metallic surface is plated with an immersion silver plate prior to soldering, which immersion silver plate is treated with an additive selected from the group consisting of fatty amines, fatty amides, quaternary salts, amphateric salts, resinous amines, resinous amides, fatty acids, resinous acids, ethoxylated derivatives of any of the foregoing, and mixtures of any of the foregoing. The immersion silver deposits created are resistant to electromigration.

Abstract: The quality of painted surfaces of polymer composites is improved by first forming an electroless metal coating on the molded surface of the composite and then electroplating a coating of zinc or zinc alloy on the metallized composite surface. The “galvanized” composite surface provides a good base for electrostatic deposition of either liquid or powder paint and the zinc surface prevents the formation of defects in the painted surface during heating of the composite to dry or cure the paint film.

Abstract: In a method of fabricating an array of microstructures, a substrate with an electrically-conductive portion is provided, an insulating mask layer is formed on the electrically-conductive portion of the substrate, a plurality of openings are formed in the insulating mask layer to expose the electrically-conductive portion, and a first plated or electrodeposited layer is deposited in the openings and on the insulating mask layer by electroplating or electrodeposition. A second plated layer is further formed on the first plated or electrodeposited layer and on the electrically-conductive portion by electroless plating to reduce a size distribution of microstructures over the array.

Abstract: Provided is a method for the application of a polymer coating to an internal surface of a container, which method comprises: (a) heating the inside surface of the container to be coated; (b) spraying an aqueous suspension of a fluorine-containing polymer onto the surface to form a coating on the surface; and (c) sintering the coating; wherein the container comprises a base and one or more side walls defining a container opening and is suitable for storing a medicament, and wherein the spraying step is conducted with a first spraying means configured to produce an axial spray pattern that is substantially conical about an axis perpendicular to the container base.

Abstract: An article includes a bi-colored metallic coating electrodeposited directly on a metallic cathode, such that a planar surface of the coating exhibits a visual first color when viewed from a first angle to the surface and a visual second and different color when viewed at a second angle to the surface. The electrode position is carried out from a bath which comprises ions selected from the group consisting of molybdenum(VI)-containing ions and (Ni(II)−+Zn(II))− containing ions, wherein the parameters ionic concentration, pH, bath temperature current density and current quantity are so selected that a bi-colored coating is obtained, provided that a current density is applied to the underplate as cathode within the range of 0.005 to 0.5 A/dm2.

Abstract: A low friction, low contact resistance coating for electrical terminal members, especially members made of copper base alloys and low carbon steel alloys and plastics, is formed of a coarse electroplate of tin or silver characterized by grains having an average dimension in the range of about 0.5 to 10 micrometers where such grains carry very small particles of polytetrafluoroethylene or the like having average diameters in the range up to about 0.30 micrometers.

Abstract: Before the application of an external coating having a base of polyester or epoxy resin, or of a mixture of the two by spraying with an electrostatic spray gun, the parts to be coated are subjected to an initial zinc coating treatment by electrolytic process and a layer of an acrylic paint is applied to the zinc coating and polymerized to define a bonding sublayer between the metal and the external coating.

Abstract: A method is provided for enhancing the adhesion of organic polymer coatings to electrolytically passivated (CDC) tin-plated steel strip. The method includes applying a solution comprising 0.1 to 7 percent of an adhesion promoter to the electrolytically tin-plated strip during the processing of the strip on an electrolytic tin-plating line. The adhesion promoter may be at least one selected from the group consisting of: where n is within a range of from 4 to 99; (b) C16H33+N(CH3) 3 M where M is member of the halogen group; and (c) Rn—Si—(X)4−n where R is a non-hydrolyzable organic radical selected from the group consisting of glycol, epoxy, amine, diamine or mercapto groups, and mixtures thereof, containing from 3 to 10 carbon atoms; the number n is an integer from 1 to 3; and X is a hydrolyzable group selected from the group consisting of Cl—, OCH3, OCH2CH5, OOCCH3, OCH2OCH3, amine, diamine, triamine, acyloxy and alkoxysilanes, and mixtures thereof.

Abstract: A method for making an aluminium material which is electroplated on its aluminum or aluminium alloy base with iron or an iron alloy containing 2-20 weight % of chromium, and which can be utilized as a new structural or functional material in various industrial fields. The material is characterized in having an inter-diffusion layer produced between the base and the plating and/or having such fine cracks produced in the plating which can reserve well machine oil, work well for painting it, and be impregnated with a resin for improving its wear resistance and so on.

Abstract: A method for coloring tool bits includes cutting a beam having a hexagonal cross section into a number of segments. The segments are electroplated for forming an outer layer on the segments. The segments each have one or two of the ends machined to form a tool bit end for engaging with fasteners. The segments are then dyed for allowing color material to be attached onto the tool bit end and for coloring the tool bit end. The electroplated outer layer may prevent the color material from attaching onto the outer peripheral portion of the segments.

Abstract: A copper foil for printed circuits of which a shiny side has resin dust resistance, excels in heat discoloration resistance and rust preventiveness, and does not adversely affect the solderability and resist adhesion, and a method of treating the surface of such copper foil. The copper foil for a printed circuit comprises a first layer of zinc alloy composed of zinc and nickel and/or cobalt, formed on the shiny side surface of a copper foil, and a second layer composed of a mixture or compound of benzotriazole derivative and phosphorus compound (and silicon compound) formed on the layer. The method for treating the surface of a copper foil for a printed circuit comprises the steps of forming a first layer of zinc alloy composed of zinc and nickel and/or cobalt by electroplating on the shiny side surface of a copper foil, and forming a second layer by immersing it in an aqueous solution of benzotriazole derivative and phosphorus compound (and silicon compound).

Abstract: The surface protection material for printed circuit boards disclosed is one in which a compound having a benzimidazole derivative as an effective component is adjusted to pH range from 1 to 5 with a salt-forming acid and which is an aqueous solution whose metal content of such a heavy metal as copper, manganese and zinc is not higher than 50 ppm. A copper or copper alloy circuit section surface is brought into contact with the surface protection material aqueous solution, and by using an ion exchange resin or by electrolysis, ions of the heavy metal dissolved out of the circuit section surface due to the contact thereof with the surface protection material aqueous solution are removed. The concentration of the heavy metal in the surface protection material aqueous solution is held within 50 ppm. A surface protection film is formed only on the element mounting pad without being formed on a gold plating layer on a terminal, and this enhances the contact reliability of circuits.

Abstract: Electroplated steel sheet suitable for soldering is provided herein by coating the plated steel sheet with a post-treatment solution in the range of 0.02 to 2 .mu.m in dry thickness. The post-treatment solution contains from 2 to 100 g/l of at least one water-soluble or water-dispersed material. The post-treatment solution may further contain chromium ion, hereafter referred to as Cr.sup.6+, from 0.01 to 3 g/l, and/or organic amine soap from 10 to 100 g/l. A suitable pH value of the post-treatment solution is from 3 to 10.

Abstract: A corrodible iron-based work such as a cylinder rod is subjected to hard chrome plating, heat-treatment by high frequency heating or baking at a temperature of not less than 150.degree. C. (e.g. 170.degree. to 600.degree. C.), resin impregnation treatment and finish buffing in that order to produce a corrosion-inhibited member. In the impregnation step, a thermosetting resin may be impregnated under subatmospheric pressure. After the impregnation step, the thermosettable resin or sealant may be cured in a curing step. The present invention provides for an remarkably high degree of corrosion resistance even though the thickness of the hard chrome plating layer is small.

Abstract: An improved process for reflowing tinplate by treating a matte finish of tinplate with a flux, and reflowing the fluxed matte tinplate to produce bright tinplate, wherein the flux is a naphthalenesulfonic compound, preferably having the a naphthalene ring which is substituted with at least one --SO.sub.3 M group where M is hydrogen, an alkali metal or an alkaline earth metal and is optionally substituted with at least one hydroxy group. The flux is preferably applied to the matte tinplate in an aqueous solution which may contain an acid. The most preferred fluxes are 2-naphthol-6,8-disulfonic acid, 1-naphthol-3,6-disulfonic acid, and dipotassium 2-naphthol-6,8-disulfonate.