核电堆内构件紧固件镀铬工艺研究

Study on chromium electroplating process for fasteners of nuclear reactor internals

以核电堆内构件螺栓为基体电镀硬铬,研究了镀液铬酸酐质量浓度、温度和电流密度对镀层性能的影响。结果表明,镀液温度和铬酸酐质量浓度对镀铬层显微硬度的影响较大,电流密度的影响较小,较佳的工艺条件为:CrO_(3)质量浓度230 g/L,温度55~60℃,电流密度25~35 A/dm^(2)。该条件下制备的镀铬层显微硬度、结合力、成分、厚度等均满足设计要求。

Hard chromium was electroplated on the bolts of nuclear reactor internals.The effects of CrO_(3) mass concentration,bath temperature,and current density on the properties of chromium coating were studied.The results showed that the microhardness of chromium coating was affected greatly by both temperature and CrO_(3) mass concentration,while slightly by current density.The optimal process conditions are as follows:CrO_(3) mass concentration 230 g/L,bath temperature 55-60℃,and current density 25-35 A/dm^(2).The microhardness,adhesion strength,elemental composition,and thickness of the chromium coating obtained thereunder meet the technical requirements.