摘要:
A thin-film humidity sensor for measuring the absolute humidity having a base electrode, a moisture-sensitive dielectric layer and a top electrode is formed at the end face of an electrically insulating bushing body by the thin-film technique. The connecting conductors are led through the bushing body and terminate in contact areas which are ground plane and polished together with the end face of the bushing body. The metal layers forming the electrodes are so shaped on application, preferably by means of perforated masks, that they each cover the contact area of the associated connecting conductor and are electrically connected thereto. The bushing body is inserted into a sleeve of a highly alloyed nickel-molybdenum compound and connected thereto in pressure-resistant manner.
摘要:
The invention relates to a pressure measuring cell comprising a base body, a membrane that is connected to the base body, thus forming a measuring chamber. During operation, the membrane is subjected to a deflection which is dependent on a pressure that is to be measured. The cell also comprises a membrane bed, formed by a surface of the base body that faces the membrane, at least one electrode being mounted on said bed. Said electrode, together with a counter-electrode that is mounted on the membrane, forms a capacitor, whose capacitance represents a measurement for the deflection of the membrane. The measuring cell is characterized in that the electrode is electrically connected through the base body and that the measuring chamber has a smooth surface in the contact zone, said surface having a contact pin that is guided in a bore through the base body. The electrode is electrically connected by means of said pin for measuring the capacitance and the pin is soldered into the bore on the membrane side, using a solder. The contact pin, the solder and the membrane bed form a smooth surface.
摘要:
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.
摘要:
This relative-pressure sensors has virtually no zero offset at relative humidities up to near the saturation limit. The sensor has a diaphragm (11) having a surface on which a electrode (13) is deposited and a substrate (12) having a bore (23) for guiding reference air from af first surface to an opposite surface. The first surface is polished and provided with at least an addional electrode (15). The substrate and the diaphragm are soldered or brazed together along the periphery by means of a spacer (20) to form a chamber which is covered from inside with a thin layer (24) of hydrophobic material that is introduced through the bore after the soldering or brazing.
摘要:
A pressure sensor is provided having a housing, a process connection which is connected to the housing and serves to feed a medium whose pressure (p) is to be measured to a membrane which his arranged in the housing, said membrane, in operation, undergoing a deflection which depends on the pressure (p) which is to be measured, which pressure sensor can have a seal made of a chemically highly resistant material and in which the membrane can consist either of ceramic or metal, which pressure sensor has a seal which seals a gap found between the housing and the process connection and/or the membrane, bears directly against the gap and covers the gap, and which is clamped between the housing and the membrane, and which pressure sensor has a spring which is two-legged in cross section, whose first and second legs enclose an acute angle, whose first leg has a leg surface which faces away from the second leg, rests on a supporting surface and is connected fixedly to the latter, and whose second leg has a leg surface which faces away from the first leg, bears in a planar manner against the seal and exerts a spring force on the seal, which spring force acts in the direction of the gap.
摘要:
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.
摘要:
In this method for producing capacitive alumina-ceramic absolute pressure sensors sorted in high-precision zero-point long-term stability defect classes referred to a measured-value span c.sub.sp, the sensors are firstly produced conventionally: a substrate is provided with an annular first electrode and, at the center, a circular second electrode insulated from the first; a diaphragm is provided with a third electrode, and the substrate and diaphragm are joined tightly together in a vacuum by the mutually facing electrodes, at an outer edge through the interposition of an active brazing ring with the formation of a chamber, with the result that a pressure-dependent capacitance C.sub.p and a pressure-independent capacitance C.sub.r are produced. Then, using the equation c=(C.sub.p -C.sub.r)/C.sub.p =k.sub.1 (p-p.sub.0)+k.sub.0, at room temperature and under a vacuum (=p.fwdarw.0) a first zero value c.sub.n1 =-k.sub.1 p.sub.0 +k.sub.0 is determined by means of a capacitance zero-point measuring device having the zero-point measuring error F.sub.n. A second zero value c.sub.n2 =-k.sub.1 p.sub.0 '+k.sub.0 is determined for each sensor by means of the same measuring device after the sensors have been stored in a gas during a period t in such a way that the pressure and/or temperature of the gas was raised, or its molecular weight was lowered, with respect to normal atmospheric conditions. Then the difference .delta.c.sub.n between the first and second zero values .delta.c.sub.n =c.sub.n1 -c.sub.n2 =-k.sub.1 .delta.p.sub.0 is formed, and the value .delta.c.sub.n /c.sub.sp is compared with the value F.sub.n /c.sub.sp. It is also possible to make use analogously of the zero-point temperature coefficient.
摘要:
A mechanically heavily loadable and high-vacuum-tight feedthrough connection through a hole (2) of a high-temperature-resistant and vacuum-proof insulating part (1), particularly of ceramic, glass, or a single crystal, is disclosed which can be produced in a single high-temperature step and is thus inexpensive. It is designed as a terminal lead (4) covered with active solder and soldered into the hole, the terminal lead having a coefficient of thermal expansion less than that of the insulating part (1). The feedthrough connection is preferably used in a capacitive pressure sensor (10) having a diaphragm (11) and a substrate (12) which have spaced-apart, flat inner surfaces which are provided with at least one conductive layer (14, 15) for forming at least one capacitor and are electrically connected to the respective rear side via the feedthrough connection.
摘要:
A method for manufacturing an elastic deformation body made of an Al2O3 ceramic, according to which a highly pure alumina having at most 2000 ppm MgO, at most 200 ppm inorganic impurities, a specific surface of at least 10 m2/g, an average grain size of at most 0.3 μm is applied. With the alumina and additives, there is produced via aqueous processing a homogeneous mixture, from which a pressable spray granulate is produced, which is formed by means of a uniaxial pressing method to a homogeneous, green body, which is subjected to a sinter process. The resulting elastic deformation body has a bending fracture stress σc, whose distribution F(σc) is given by the Weibull parameters σ0≧800 MPa and m≧24, with an average grain size of the sintered material of no more than 2 μm, and wherein the sintered material of the deformation body has a density of not less than 3.98 g/cm3.
摘要翻译:一种制造由Al 2 O 3陶瓷制成的弹性变形体的方法,根据该方法,具有至多2000ppm MgO,至多200ppm无机杂质,至少10m 2 / g比表面积的高纯度氧化铝,平均粒径 最多0.3μm。 使用氧化铝和添加剂,通过水性加工生产均匀的混合物,通过单轴压制方法制备可挤压的喷雾颗粒,该均匀的混合物经受烧结过程的均匀的生坯。 所得到的弹性变形体具有弯曲断裂应力σ,其分布F(&sgr; c)由Weibull参数&sgr;0≥800MPa和m≥24给出,烧结材料的平均晶粒尺寸为no 大于2μm,并且其中变形体的烧结材料具有不小于3.98g / cm 3的密度。
摘要:
The pressure sensor consists of a substrate and a diaphragm joined together around the periphery so as to form a chamber. The surface of the diaphragm facing away from the substrate is exposed to a medium whose pressure is to be measured. To protect the diaphragm against corrosion or abrasion, the diaphragm surface exposed to the medium is covered with a layer of silicon carbide, preferably by chemical vapor deposition.