Abstract: The active brazing solder for brazing ceramic parts of alumina, particularly of high-purity alumina, contains a maximum of 12 wt. % Ti, a maximum of 8 wt. % Be, and less than 16.5 wt. % Fe, the remainder being Zr and any impurities that may be present. The active brazing solder has the following behaviour/features: Brazing temperature: lower than 1,000° C.; the brazed joint is high-vacuum-tight over a long period of time; the coefficient of thermal expansion of the active brazing alloy is substantially identical to that of the alumina ceramic in the entire temperature range covered during the brazing process; the strength of the brazed joint between the two ceramic parts is so high that under tensile loading, fracture will result not at the joint, but in the adjacent ceramic; the pressure resistance of the active brazing solder is greater than 2 GPa; the active brazing solder is very good processable into powders having particle sizes on the order of 10 &mgr;m.

Abstract: A diaphragm 30 and basic body 20 of a pressure sensor 10 are interconnected via a joint F. A groove 26 is provided in the basic body 20 in order to reduce the stress concentration in the region of the joint F.

Abstract: The active brazing solder for brazing ceramic parts of alumina, particularly of high-purity alumina, contains a maximum of 12 wt. % Ti, a maximum of 8 wt. % Be, and less than 16.5 wt. % Fe, the remainder being Zr and any impurities that may be present. The active brazing solder has the following behaviour/features: Brazing temperature: lower than 1,000 ° C.; the brazed joint is high-vacuum-tight over a long period of time; the coefficient of thermal expansion of the active brazing alloy is substantially identical to that of the alumina ceramic in the entire temperature range covered during the brazing process; the strength of the brazed joint between the two ceramic parts is so high that under tensile loading, fracture will result not at the joint, but in the adjacent ceramic; the pressure resistance of the active brazing solder is greater than 2 GPa; the active brazing solder is very good processable into powders having particle sizes on the order of 10 &mgr;m.

Abstract: The active brazing solder for brazing ceramic parts of alumina, particularly of high-purity alumina, contains a maximum of 12 wt. % Ti, a maximum of 8 wt. % Be, and less than 16.5 wt. % Fe, the remainder being Zr and any impurities that may be present. The active brazing solder has the following behaviour/features: Brazing temperature: lower than 1,000° C.; the brazed joint is high-vacuum-tight over a long period of time; the coefficient of thermal expansion of the active brazing alloy is substantially identical to that of the alumina ceramic in the entire temperature range covered during the brazing process; the strength of the brazed joint between the two ceramic parts is so high that under tensile loading, fracture will result not at the joint, but in the adjacent ceramic; the pressure resistance of the active brazing solder is greater than 2 GPa; the active brazing solder is very good processable into powders having particle sizes on the order of 10 &mgr;m.

Abstract: A diaphragm 30 and basic body 20 of a pressure sensor 10 are interconnected via a joint F. A groove 26 is provided in the basic body 20 in order to reduce the stress concentration in the region of the joint F FIG. 2).

Abstract: These active brazing pastes satisfy the requirements for screen printing or dispensing particularly well and are well suited for brazing one aluminum oxide ceramic body to another one or to a metal body. This can be done by means of respective regions of brazing paste applied by screen printing to the ceramic bodies, with the coverage of one region matching the coverage of the other region or by inserting the metal body into a hole in the ceramic body and using a pad of brazing paste applied to the ceramic body and to the metal body by dispensing. The printable paste comprises as the active brazing material a hydrogenated powder of a Zr/Ni/Ti alloy or a Zr/Fe/Ti/Be alloy and as an organic vehicle poly(butyl-methyl methacrylate) or poly(n-decyl methacrylate) as the polymer and the camphor ketal of 2,2,4-trime-thylpentane-1,3-diol and/or 5-nonyl-methyl ether as the solvent for the polymer.

Abstract: The active brazing solder for brazing ceramic parts of alumina, particularly of high-purity alumina, contains a maximum of 12 wt. % Ti, a maximum of 8 wt. % Be, and less than 16.5 wt. % Fe, the remainder being Zr and any impurities that may be present. The active brazing solder has the following behaviour/features: Brazing temperature: lower than 1,000.degree. C.; the brazed joint is high-vacuum-tight over a long period of time; the coefficient of thermal expansion of the active brazing alloy is substantially identical to that of the alumina ceramic in the entire temperature range covered during the brazing process; the strength of the brazed joint between the two ceramic parts is so high that under tensile loading, fracture will result not at the joint, but in the adjacent ceramic; the pressure resistance of the active brazing solder is greater than 2 GPa; the active brazing solder is very good processable into powders having particle sizes on the order of 10 .mu.m.

Abstract: This process serves to form a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire. The joining material is interposed in the form of a paste, a foil, or a slip between the first body and the second body. The joining material has been made from 1) an agglomerate-free, highly disperse, high-purity .alpha.-alumina powder with particles of as high a degree of calcination as possible and of a size not exceeding 100 nm (=10.sup.-7 m), 2) an anorganic oxidic powder of an auxiliary sintering agent with particles of approximately the same size as the particle size of the .alpha.-alumina powder, 3) an organic vehicle which is dissolved or suspended in an organic or aqueous solvant and in which the particles of the respective powder are distributed as evenly as possible.

Abstract: To provide a flush-mounted and corrosion-resistant pressure sensor for measuring the pressure of a medium which, on the one hand, is very rugged and, on the other hand, has a casing (2) mechanically isolated from the sensing element (1) as perfectly as possible, and whose measured values exhibit little temperature dependence and little hysteresis, the casing (2) has an internal space (21) and is preferably pot-shaped for receiving the sensing element (1). An annular, particularly annular-disk-shaped, flexible connecting element (3), disposed between the casing (2) and the sensing element (1), and the sensing element close the interior space (21) toward the medium to be measured, and a liquid (4) fills the enclosed interior space (21).

Abstract: In an installation for continuous vegetable cultivation by the hydroponic system, a plurality of identical containers provided with lateral apertures are superimposed one on the other to create at least one vertical hollow column, provided at regular intervals along its axis with equidistant coplanar apertures (levels of culture) arranged for the insertion of plants. Means are provided for raising and lowering the column and for keeping it vertical, these means being in the form of a cable which is removably fixed to each individual container, and means for spraying nutrient liquid at the top of the column and collecting said liquid at the base, to recycle it to the top.