9.1下列哪种磁粉检测设备和器材不需要定期校验?( )

**解析：** 磁粉检测中，为了保证检测结果的准确性和可靠性，关键的设备参数和性能指标需要定期进行校验或检查。我们逐一分析各个选项： 1. **A. 电流表**： 磁粉检测 relies heavily on the magnitude of the magnetizing current (whether AC, DC, or rectified). The accuracy of the ammeter directly affects whether the required magnetic field strength is achieved. Therefore, ammeters must be regularly calibrated (usually annually or as per specific standards like ASTM E1444 or GB/T 15822) to ensure they read correctly. 2. **B. 黑光辐照计**： In fluorescent magnetic particle testing, the intensity of the ultraviolet (UV-A) light is critical for detecting indications. The black light radiometer (or UV-A meter) is used to measure this intensity. Since the sensor's sensitivity can drift over time, the radiometer itself must be regularly calibrated against a standard source to ensure accurate measurements of the black light intensity. 3. **D. 黑光灯**： The performance of the black light source (intensity and wavelength) needs to be checked regularly (often before each use or daily/weekly depending on the standard) to ensure it meets the minimum requirements (e.g., ≥1000 µW/cm² at 38cm). While "calibration" might strictly apply to the meter, the *performance* of the black light system is subject to regular verification/checks. In the context of equipment maintenance, ensuring the light output is within spec is a mandatory periodic check. 4. **C. 通电线圈的电阻值**： The resistance of a magnetizing coil is a physical property determined by its material, length, cross-sectional area, and temperature. While a significant change in resistance *could* indicate a fault (like a short circuit or broken wire), the resistance value itself is **not** a parameter that requires periodic *calibration* or *verification* against a standard in the same way measuring instruments do. As long as the coil delivers the required ampere-turns (NI) and the current is monitored by a calibrated ammeter, the specific resistance value does not need to be regularly "checked" or "calibrated" as part of the standard quality assurance protocol for detection sensitivity. It is a static characteristic of the hardware, not a measuring instrument or a variable process parameter that drifts and affects interpretation directly if unmonitored by other means. **结论：** 电流表和黑光辐照计属于测量仪器，必须定期校准以保证读数准确；黑光灯的性能需定期验证以确保检测灵敏度；而通电线圈的电阻值是线圈本身的固有属性，不需要像测量仪器那样进行定期的“校验”（Calibration/Verification of measurement accuracy）。 因此，正确答案是 **C**。