188.8.131.52 Particle size distribution. The silica particle size
distribution shall be determined in accordance with ASTM-B-214 using
the required sieves.
184.108.40.206 Loss on ignition. The loss on ignition shall be
determined by drying a sample of the lot of silica at 200
10F for 24 hours minumum. A 5 gm sample shall then be accurately
weighed placed in a muffle furnace and ignited at 950 15C
for a minimum of two (2) hours. The sample shall be cooled in a
desiccator and reweighed. The percent of loss on ignition shall be
calculated as follows:
220.127.116.11 Silicon dioxide content. The silicon dioxide content
may be determined by the wet analysis method as follows:
Weigh accurately about 0.5 gram of the material. Transfer to a
250 ml beaker and boil for 30 minutes with 50 ml of hydrochloric
Filter on a double ashless filter
acid (1:1). Add 50 ml water.
Transfer filter and residue to a tared platinum
paper . Wash.
Weigh the insoluble residue. The insoluble residue
shall then be volatilized with 0.5 ml of sulfuric acid and 10 ml
(1:1) hydrofluoric acid.
(Add the hydrofluoric acid very cautiously
to avoid mechanical loss from the vigorous reaction set up between
Ignite to drive off white
Evaporate under a hood.
fumes, then weigh. The loss in weight in the insoluble residue from
volatilization will be the total silica
digestion until weight loss on repetitive trials is less than 2%
The contractor may use x-ray analysis or other suitable test
method if approved by the Contracting Officer and submitted as
specified in 4.4.4.
5.1 Packaging. The base resin and hardener shall each be
packaged in widemouthed containers as specified by the procuring
5.2 Marking. All marking shall be clear and legible and shall
include as a minimum:
Item identification and lot number
Date of manufacture
Title and date of revision of this Military Specification
Safety precaution warnings