RJ-5熔劑在RJ-2熔劑的基礎上加入了一定量的氟化物，進一步增強熔劑的擴散性能，表面張力和化學穩(wěn)定性。其熔點和比重較鎂合金低，撒在上面，能起到熔體和空氣的隔絕作用，減少金屬在熔煉過程中的氧化、燃燒。主要用作合金覆蓋和精煉。

It is the RJ-2 flux with some fluoride.The melting point and specific gravity are lower than magnesium alloy which can isolate with the air to prevent the oxidation and burning.It is used in the refining.