摘要:
A ceramic consisting substantially of Al.sub.2 O.sub.3 as ceramic support, ceramic cover layer and/or ceramic supporting structure for heating conductors is described, which is electrochemically stable, which, in other words, does not decompose on application of a heating voltage, even in long-term operation at temperatures above 600.degree.. Such a ceramic exhibits a very small alkali metal content, of less than 0.2% by weight Na.sub.2 O and K.sub.2 O respectively. Particularly favorable processing, in particular pressing properties are exhibited by such a ceramic if it has 2.5 to 10% by weight of barium silicate or strontium silicate fluxes, the proportions of Na.sub.2 O, K.sub.2 O, CaO and MgO together make up less than 1% by weight, and the BaO or SrO:SiO.sub.2 molar ratio is between 2:1 and 1:12.5. Such a ceramic with a BaO:SiO.sub.2 ratio of 2.6:1 parts by weight is electrochemically stable up to approximately 1400.degree. C., and at 1300.degree. C. still exhibits a bending strength of approximately 300 N/mm.sup.2.
摘要:
To decrease the preheat time and power requirements in preheater-type glow plugs for Diesel engines, a closed ceramic tube (20), for example of aluminum oxide and of about 5 mm diameter has, on the bottom (21) thereof applied a layer or film-like heater element (24, 24'), for example in an undulating or zig-zag configuration (FIG. 2) or in form of a constriction or pinch (FIG. 4: 24') to provide a concentrated point or strip source of heat. The heater layer itself is protected by a protective coating (25) and, to provide for the required heat distribution, the underlying bottom (21, 21') of the tube (20, 20') supports an insulating intermediate layer and possibly a heat conductive layer is intermediate. Preheat times in the order of 1-2 seconds, with lower current consumption than prior wound-wire plugs can be obtained.
摘要:
Functional polymers having silyl end groups are prepared in a continuous process by polymer analogous reaction of a reactive polymer and inter-reactive silane. The polymer products are surprisingly uniform in properties and exhibit higher physicochemical properties as well.
摘要:
Isocyanate-functional silanes, particularly isocyanate-functional α-silanes, are prepared in good yield by a liquid phase thermolysis conducted in the presence of a catalyst at a pressure of >100 mbar, or >80 mbar when a thin-film evaporator is used.
摘要:
The invention provides a process for preparing silanes which possess an isocyanate function, in which the silanes, after their chemical preparation, are purified and, after the purification, are handled exclusively in an atmosphere with a relative air humidity below 10%.
摘要:
A method for producing ceramic bodies, particularly ceramic foils, from a castable slip made of a dispersion of a ceramic powder in a solvent. A dispersion of an aqueous vinyl-acetate homopolymer or an aqueous vinyl-acetate/ethene copolymer being used as the solvent.
摘要:
Lead frames completely surface-plated with palladium have a nickel-phosphorus or copper-tin layer between the base element, made for example of copper, and the palladium layer. Such lead frames exhibit good bondability and good solderability without tinning.
摘要:
In a magnetometer with an inhomogeneous magnetic field which timewise changes in its intensity periodically and acts upon the specimen to be measured, the latter being attached to the free end of a tongue (8) that can be oscillated and whose oscillations can be determined by piezo elements (12, 13), there occurs a compensation of the magnetic moment of the specimen with the aid of a compensating current loop (33). The current required for arresting the oscillations is a measure of the magnetic moment to be determined. An adaptation to the resonance frequency of the oscillating tongue (8) is effected through a frequency control cirucit (22, 28, 6), making it possible to measure large temperature ranges at great sensitivity and contingent on temperature.
摘要:
To sense pressure within the combustion chamber of an internal combustion engine (ICE), a plug element which already extends into the combustion chamber of the ICE, such as a sparkplug, or a glow plug, has a layer-like resistor applied to a ceramic insulator extending into the combustion chamber, for example, directly on the central insulator of a sparkplug or on the side of a ceramic glow plug bushing or plug element. If applied to a sparkplug then, preferably, the heater is shielded by metallic layers, separated from the metallic shielding layers by insulating layers, of which the top metallic layer preferably is platinum or a platinum-type metal to catalyze combustion of residues which, otherwise, might collect on the top layer and interfere with proper sensor operation. The layer-like sensor and conductive tracks may be of thick film construction; stamp-on printing with flexible printing stamps is suitable to apply the layer-like resistors.
摘要:
A coating formed on a substrate is provided which coating comprises (a) an organic NIR-transparent pigment and/or an inorganic NIR-reflective pigment; (b) a dye having a transmittance of at least 75% in the range of from 700 to 2500 nm; and (c) optionally an effect pigment; wherein said coating exhibits a total solar reflectance (TSR) of (i) ≥40%, if 60