The present invention relates to processes for producing fluorine-containing compounds by means of precipitation reactions from solutions containing fluoride ions wherein the pH value is determined using an electrochemical measuring chain and to electrochemical measuring chains for determining pH values.

Disclosed is an aluminum composite material including an aluminum alloy material containing magnesium, and a bonding material formed by brazing using a flux, the bonding material being adapted to bond the aluminum alloy material thereto. In the aluminum composite material, the bonding material contains a magnesium-containing compound other than KMgF.sub.3 and MgF.sub.2. The present invention provides an aluminum composite material with satisfactory brazeability to an aluminum alloy material containing magnesium, a heat exchanger including the aluminum composite material, and a flux suitable for use in braze.

The present invention relates to a metal paste including: a first metal powder including nickel (Ni); a second metal powder including at least one selected from the group consisting of tin (Sn), zinc (Zn), bismuth (Bi), and indium (In); and a dispersing agent, and to a thermoelectric module which adopts a bonding technique using the metal paste.

A braze gel includes a braze powder, a braze binder, and a viscosity reducer. The braze gel has a gel viscosity sufficiently low to permit dip coating of a component with the braze gel to apply a braze coating of the braze gel to the component. A brazing process includes applying the braze gel to a portion of a component. The brazing process also includes drying the braze gel to form a braze coating on the component to form a braze-coated component. A brazing article includes a component and a braze coating over a portion of the component. The component may have structural features having a spacing of less than about 5 mm and a depth of at least about 1 mm, which may be honeycomb cells. The component may be a turbine component.

A method of fabricating a joining preform includes the step of printing a self-fluxing joining alloy. Joining includes brazing and soldering. The self-fluxing joining alloy contains at least one of phosphorus, boron, fluorine, chlorine, or potassium. Another printing step prints a non-phosphorous joining alloy. Both printing steps are performed by an additive manufacturing or 3D printing process. The printing a self-fluxing joining alloy step may be repeated until the non-phosphorous joining alloy is substantially encapsulated by the self-fluxing joining alloy. The self-fluxing joining alloy may be a BCuP alloy, a CuP alloy, a CuSnP alloy, a CuSnNiP alloy or a CuAgP alloy. The non-phosphorous joining alloy may be a BAg alloy, a BNi alloy or a BAu alloy.

The invention relates generally to welding and, more specifically, to electrodes for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. The core includes a carbon source and a potassium source that together comprise less than 10% of the core by weight. Furthermore, the carbon source is selected from the group: carbon black, lamp black, carbon nanotubes, and diamond.

A braze gel includes a braze powder, a braze binder, and a viscosity reducer. The braze gel has a gel viscosity sufficiently low to permit dip coating of a component with the braze gel to apply a braze coating of the braze gel to the component. A brazing process includes applying the braze gel to a portion of a component. The brazing process also includes drying the braze gel to form a braze coating on the component to form a braze-coated component. A brazing article includes a component and a braze coating over a portion of the component. The component may have structural features having a spacing of less than about 5 mm and a depth of at least about 1 mm, which may be honeycomb cells. The component may be a turbine component.

A flux (55) for superalloy laser welding and additive processing (20, 50), including constituents which decompose when heated in a laser induced plasma or to a melt temperature of the superalloy (42), creating one or more gases (46) that blanket the melt to protect it from air, while producing not more than 5 wt. % of slag relative to the weight of the flux. Embodiments may further include compounds providing one or more functions of surface cleaning, scavenging of impurities in the melt, and elemental additions to the superalloy.

A method for manufacturing a heat exchanger (1) includes joining an inner fin (3) to a hollow structure (20) formed from at least two clad plates (200a, 200b) by heating and brazing a filler metal layer (B). Each clad plate has a core layer (A) composed of an aluminum alloy that contains Mg: 0.40-1.0 mass %. The filler metal layer is composed of an aluminum alloy that contains Si: 4.0-13.0 mass %, and further contains Li: 0.0040-0.10 mass %, Be: 0.0040-0.10 mass %, and/or Bi: 0.01-0.30 mass %. The inner fin is composed of an aluminum alloy that contains Si: 0.30-0.70 mass % and Mg: 0.35-0.80 mass %. A flux (F) that contains cesium (Cs) is applied along a contact part (201), and the vicinity thereof, of the at least two clad plates prior to the heating. A heat exchanger (1) may be manufactured according to this method.

A method of ultrasonic additive manufacturing comprising using ultrasonic additive manufacturing to build a solid metal object through ultrasonically welding successive layers of thin metal foil into a three-dimensional shape; machining internal features into the solid metal object, wherein the internal features include voids, chambers, cavities, channels, or conduits; depositing a sacrificial support material in the internal features, wherein the sacrificial support material includes at least one water-soluble solid, and at least one water-soluble binding agent; curing the sacrificial support material at a predetermined temperature for a predetermined period of time within the internal features; using ultrasonic additive manufacturing to deposit additional successive layers of metal on top of the sacrificial material and solid metal object to complete the solid metal object; and introducing a solution containing water into the internal features to dissolve and remove the sacrificial support material therefrom.