PLTL-21 Total Insolubles per FED-STD-791 method 3710 (per SAE-AMS-M-7866)
Insoluble matter in molybdenum disulfide powder, particularly abrasive matter may alter lubricating properties. This method determines the amount of insoluble matter in MoS2 powders.
The oil-free, moisture-free sample from PLTL-20 is put through a series of extractions and washings resulting in the insoluble residue on a filter paper. The filter paper is placed in a crucible, carefully burned, muffled, cooled and weighed. The muffle – cool – weigh sequence is repeated until a constant weight is obtained. The total percent of insoluble matter is calculated and reported.