Degussa Aktiengesellschaft

Other

Degussa-Huls Aktingesellschaft

Saxonia Technical Materials Gmbh

Wolfgang Weber

Peter Biberbach

Hans-Hermann Beyer

Klaus Zimmermann

J&uuml;rgen Koch

Karl-Anton Starz

Juergen Koch

Ulrich Baudis

Manfred Koschlig

Harald Krappitz

Roland Gerner

Wolfgang Kohlweiler

Sandra Wittpahl

Klaus Schmitt

Klaus L&ouml;nne

Mathias Metzner

Max Schimpfermann

A flux based on inorganic boron and/or halogen compounds for brazing difficult to wet metallic materials with silver- and copper-based solders, which contains, as an activating addition, based on the total amount of the flux, 0.01-10 wt. % of elemental boron and 0.01-10 wt. % of at least one of the elements Mo, W, Mn, Co, Ni, Pd, Cu or Ag in the form of elements, alloys or compounds. The activating addition brings about a substantial increase in the wettability by the solder, particularly in the case of difficult to wet stock materials.

Flux for brazing difficult to wet metallic materials

A process for producing, on a metallic substrate, a geometric metal structure having a precise contour, including the steps of: solder coating a solder paste onto the substrate by screen printing to create the geometric metal structure, the solder paste comprising an organic binder system, and 80 to 95 weight % of a mixture of a nickel-based solder and a pulverulent alloy of nickel with at least one member selected from the group consisting of chromium, molybdenum, tungsten, manganese and iron, provided as a higher-melting metallic filler, wherein a weight ratio of solder to filler is 2-6:1, an average grain size of the solder is between 10 and 50 &mgr;m, and a grain size ratio of solder to filler, relative to the average grain size is from 0.5-2.5:1; drying the structure; decomposing the organic binder system present in the solder paste, without leaving a reside, by a heat treatment; and raising the temperature until the resulting solder material liquifies.

Soldering paste for producing geometrical metal structures with precise contours

Hard and scratch-proof objects of platinum and palladium or their alloys comprise a boron-containing surface layer which is 20 to 500 .mu.m thick and contains 0.3 to 1.5% by weight boron embedded in the metal lattice.

Surface-hardened objects of alloys of platinum and palladium and method

A generally flat composite structure has building blocks in the form of a plurality of multipurpose plastic building components. Each of the components includes an encompassing outer frame having a lateral surface and an interior. At least one coupling device is disposed at the lateral surface for joining two adjacent building components. Crosswise members and lengthwise members divide the interior of the outer frame into a grid of individual openings. The outer frame and the crosswise and lengthwise members are formed of plastic waste having been previously comminuted, then melted down and then injected or cast into a suitable mold. A method for laying out the components includes seeding or grassing down the components individually or in the composite structure before laying out the components, and then laying out the components in a seeded or grassed down (vegetated) state.

Multipurpose plastic building component and method for laying out such

A solder suspension is disclosed of solder powder, organic binder, organic solvent, and, if necessary, flux, with which it is possible to apply solder layers without cracks and pores to substrates by means of immersion or spraying. The solder powder must have a particle size of 5 to 50 .mu.m, where 55 to 70% of the particles are smaller than the particle size at the maximum on the particle size distribution curve. In addition, the ratio between the average particle size of the solder powder and the density of the solder powder must be between 0.1 and 20.

Solder suspension for the application of thin layers of solder to

Wear-resistant hard material layers are prepared on a metal support by applying onto said support a mixture of hard material particles, solder particles and organic binding agents and thereafter soldering the layer by heating. The mixture thus obtained can be applied by means of immersing, screen printing, brushing, spraying or spreading. The stable suspension required for the above steps is prepared by homogeneously grinding the particles together to a particle size from 1 to 20 .mu.m and adding an organic solvent to the binding agent.

Process for the preparation of wear-resistant hard material layers on

A solder paste for fastening semiconductors onto ceramic bases in a temperature range below 380.degree. C., consisting essentially of (1) 75 to 90% by weight of a mixture of silver powder and a low-melting glass powder with the weight ratio of silver to glass being between 2:1 and 9:1 and (2) 10 to 25% by weight of an organic solvent which contains 1 to 10% by weight of a thermally readily decomposable resin, the glass powder consisting essentially of 75 to 85% by weight lead oxide, 8 to 15% by weight boron oxide, 0.5 to 10% by weight silver (I) oxide 0.5 to 10% by weight bismuth (III) oxide, 0 to 5% by weight silicon dioxide, 0 to 2% by weight aluminum oxide 0 to 2% by weight tin oxide, 0 to 2% by weight zinc oxide, the glass powder having a glass transition temperature (Tg) of 250.degree. to 300.degree. C.

Solder paste for fastening semiconductors onto ceramic bases

There is described a salt bath based on an alkali and/or alkaline earth metal halide with which there can be produced without the use of current adherent and wear resistant boride coatings on metallic workpieces. This bath contains gaseous boron monofluoride or a compound from which there is formed intermediately boron monofluoride. Advantageous there is used a salt bath containing 30-60% BaCl.sub.2, 10-25% NaCl, 1-20% boron oxide or borate, 10-30% NaF, and 1-15% B.sub.4 C.

Salt bath for the currentless production of wear resistant boride layers

For removing and dissolving sand mold residues from cast parts, particularly sand mold residues containing zirconium oxide and titanium oxide, there have previously been used mechanical and electrochemical processes in salt melts. However, these processes are very expensive, attack the surface of the cast pieces or fail to work with sand mold constituents which are difficult to dissolve. These disadvantages are avoided by inserting the cast parts having adhering sand mold residues into a melt of 55 to 97 weight % of alkali metal hydroxide and 3 to 45 weight % of one or more fluorides of an element of the first to third main group of the periodic system of elements and/or zinc at 400.degree. to 900.degree. C. Preferably the salt melt additionally contains a boron-oxygen and/or a boron-fluorine compound.

Process for removal of sand mold residues from cast parts

Vanadium carbide layers are produced on iron and iron alloys having a content of at least 0.1 weight % carbon by treating the workpiece at 800.degree. to 1100.degree. C. in a salt bath which contains 1-30 weight % of vanadium or ferrovanadium powder. The salt bath consists of alkaline earth and/or alkali metal halide.

Growing community of inventors

Karlstein, Germany

Wolfgang Weber