| 摘要 |
1,150,577. Microanalyzers. BÍHLER & CO. A.G. GEB. July 14, 1966 [July 14, 1965], No.31680/66. Headings G1A and G1N. An electron beam microanalyzer is used to investigate the distribution of phases in a sample e.g. an alloy. A particular phase is indicated by one or more elements, which are present to a larger extent in one phase than in another. The electron beam is controlled to scan the surface of the sample in straight lines at constant velocity. The electron current in the sample may be detected and the phase distribution determined by applying the output of the detector to a discriminator. Also X-rays and backscattered electrons are produced and either can be detected to produce voltage variations which are applied to the discriminator (4, Fig.4 not shown). This is set to pass only voltage signals in the height range corresponding to the indicating element, to control a transistor gate (5). Pulses of constant repetition rate from an oscillator (8) are thus passed to a counter only when the phase being investigated is present in the electron beam. The counter (6) is associated with a printer (7) recording the distribution. The proportion of the phase of interest in the surface area scanned is thus obtained by comparing the number of pulses passed by the gate and counted, with the number which would have been passed if the gate had been permanently open. Instead of using a single counter (6) electronic sorting means may be provided to direct pulse trains of different predetermined durations from the gate to separate counters where the number of pulse trains of particular durations are counted. The output of the gate may also be displayed on an oscillograph. Two or more elements, indicating a particular phase, are detected by respective detectordiscriminator channels, Fig. 5 (not shown), which connect to an AND or NAND gate (9), which precedes the oscillator Control gate (5). The applications include determination of phase distribution of ferritic-austenitic steels, using nickel as the indicating element for the ferrite and austenite phases, and of sulphide-containing steels. |
