Messer Griesheim Gmbh

L'air Liquide

Messer France S.a.s.

Messer Group Gmbh

Air Liquide Deutschland Gmbh

Messer France, S.a.

Messer Austria Gmbh

Hans-Peter Schmidt

Jens Tauchmann

Tilman Schwinn

Heinz-Olaf Lucht

Philippe Grognet

Günter Wagendorfer

In a known method for producing an oxide layer on metal parts, the metal parts are heat-treated in a treatment chamber during a carburization phase at temperatures below 1100&#xb0; C. [2012&#xb0; F.] in an atmosphere containing carbon monoxide and hydrogen and then, during an oxidation phase, they are oxidized at an oxidation temperature in the range from 750&#xb0; C. to 950&#xb0; C. [1382&#xb0; F. to 1742&#xb0; F.] in an atmosphere where a PHO-to-PHratio between 0.3 and 10 has been established by feeding an oxidant into the treatment chamber, a process in which an oxide layer is formed, whereby the oxygen partial pressure is determined by means of an oxygen probe and regulated at least during the oxidation phase. In order to improve the known method in terms of the reproducibility of the formation of corrosion-resistant coatings that cover and adhere well on metal parts containing iron and so as to improve the cost effectiveness of the process, it is proposed according to the invention that the oxygen partial pressure be regulated in such a way that the oxygen probe indicates a probe voltage in the range from 890 mV to 940 mV.

Method for producing and oxide layer on metallic elements

Disclosed is a method for joint oxydation and heat treatment of workpieces at temperatures &lE;1300&deg; in the treatment chamber of an oven containing a neutral or reactive gas in a temperature range above 570&deg;. In order for the process to be reproducible and to produce homogeneous oxide layers, the PH O/PH ratio is adjusted after transformation of the workpiece structure such as found at the ambient temperature into the structure wanted during the heat treatment in such a way that the line FeO&plus;H &equals;Fe&plus;H O is exceeded and an oxide layer is formed from FEO<10 &mgr;m.

Method and device for joint oxydation and heat treatment of workpieces

A soldering apparatus has a solder container and a casing to accommodate a protective-gas atmosphere for soldering printed circuit boards. During transport of the circuit boards through a casing the circuit boards are brought into contact with a solder wave in the container. The casing has an inlet for printed circuit board on an inlet side and an outlet on its outlet side. In addition, the casing has a supply of non-oxidizing gas and an arrangement for admitting gas into the casing. The casing is designed as a modular construction kit having subassemblies and/or constructional elements which comprise an input tunnel, an entry tunnel, at least two covering elements, an outlet tunnel and a detachable connection on the solder container and/or the sub-assemblies and/or constructional elements to connect the sub-assemblies and/or constructional elements and the solder container.

Soldering device

The surface oxidation under carburization temperatures of steels during the carburization with carbon-containing gas mixtures is avoided by heating the steels to the carburization temperature under a nitrogen/hydrogen mixture or pure hydrogen. For carburization, these gases are replaced by a carbon-containing gas mixture whose oxygen activity is smaller than that required for the formation of manganese(II) oxide or chromium(III) oxide.

Process for avoiding surface oxidation in the carburization of steels

Growing community of inventors

Mettmann, Germany

Hans-Peter Schmidt