BORON CARBIDE
B 4C
MW: 55.26
METHOD: 7506, Issue 2
CAS: 12069-32-8
EVALUATION: PARTIAL
OSHA : no standard NIOSH: no standard ACGIH: no standard
7506
RTECS: None
Issue 1: 15 May 1985 Issue 2: 15 August 1994
PROPERTIES: solid; d 2.51 g/mL; MP 2350 °C
SYNONYMS: None
SAMPLING SAMPLER:
MEASUREMENT
CYCLONE + FILTER (10-mm cyclone, Higgins-Dewell (HD) + 5-µm PVC membrane)
TECHNIQUE:
X-RAY POWDER DIFFRACTION
ANALYTE:
boron carbide
FLOW RATE:
HD cyclone: 2.2 L/min nylon cyclone: 1.7 L/min
ASH:
RF plasma asher
100 L @ 1 mg/m 3 1000 L
SUSPEND:
in 2-propanol
VOL-MIN: -MAX:
REDEPOSIT:
0.45-µm Ag membrane filter
SHIPMENT:
routine
XRD:
Cu target X-ray tube Optimize for intensity; 1° receiving slit Graphite monochromator; scintillation detector Slow step scan, 0.02°/10 sec Integrated intensity with background subtraction
CALIBRATION:
standard suspensions of B 4 C in 2-propanol
RANGE:
0.1 to 2 mg per sample
SAMPLE STABILITY:
stable
FIELD BLANKS:
2 to 10 field blanks per set
BULK SAMPLE:
required; area respirable or settled dust
ACCURACY RANGE STUDIED:
not studied
BIAS:
not determined
ˆ ): not determined OVERALL PRECISION (S rT ACCURACY:
ESTIMATED LOD: 0.05 mg per sample PRECISION (Sr):
0.04 [1]
not determined
APPLICABILITY: The working range is 0.2 to 4 mg/m 3 for a 500-L air sample. The method is specific for determining respirable boron carbide among other mine dusts.
INTERFERENCES: Titanium dioxide, silver, titanium diboride, niobium oxide, silver chloride interfere; also see APPENDIX A.
OTHER METHODS: This revises P&CAM 324 [1].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
