锡-铋合金镀液浑浊故障的排除与预防

经过对锡-铋合金镀液长期浑浊故障进行分析,提出通过提高硫酸含量、加入苯酚类添加剂来减缓二价锡氧化。在硫酸为140~150 g/L,苯酚类添加剂为16~22 g/L的条件下,镀液的可使用时间最长,且镀层性能未受影响。总结了槽液调配和日常维护的注意事项,尤其要重视降温保存工作。     

Parameters for measuring the thermal shock of ceramic materials with an indentation-quench method

An indentation-quench method for measuring thermal shock has been evaluated. Experimental parameters such as sample thickness, initial crack length, and water bath temperature were surveyed. It was found that one single sample could be used throughout a whole test series of different quenching temperatures. The method can detect small differences in thermal shock resistance between materials, and was applicable to investigating thermal fatigue. The tested materials were two β-sialons with intergranular glass phase and with completely different thermal shock behaviour. The best resolution was obtained with a sample diameter Ø=12 mm, height h=4 mm, initial crack length=100 μm. and a water bath temperature=90 °C.     

无线电罗盘在(800~989)kHz自检不正常故障研究

针对某型航空器修理调试过程中发生的一例无线电罗盘在(800~989)kHz频段内自检不正常的非典型故障,在阐述机载无线电罗盘组成、自检工作原理的基础上,分析了无线电罗盘在(800~989)kHz频段内自检不正常故障产生的原因,识别并确定了故障部位,并结合实际经验给出了维修建议。对保证无线电罗盘正常使用和飞行安全具有一定借鉴意义。