特点：RJ-5熔剂在RJ-2熔剂的基础上加入了比例量的氟化物，进一步增强熔剂的扩散性能，表面张力和化学稳定性。其熔点和比重较镁合金低，撒在上面，能起到熔体和空气的隔绝作用，减少金属在熔炼过程中的氧化、燃烧。
用途：主要用作合金覆盖和精炼。
Characteristic: 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.
Purpose:It is used in the refining.