View source for 106.3.2.89 TM-89 Determination of Aluminum Oxide in High Friction Surface Treatments (HFST)

'''Scope.'''          This method tests High Friction Surface Treatments (HFST) by analytical and instrumental analysis to determine Al<sub>2</sub>O<sub>3</sub> by difference.

'''Summary of Method.''' Two samples of similar weight are fused in separate graphite crucibles containing lithium meta-borate and the fused pellets from each crucible are transferred to a 1:24 HNO<sub>3</sub> solution. The solution is brought to volume and analyzed on an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) for major and minor oxides, except Al<sub>2</sub>O<sub>3</sub>. An aliquot is taken from solution and ammonium hydroxide (NH<sub>4</sub>OH) plus methyl red are added. Aluminum, silicon, iron, phosphorus and titanium are precipitated out of solution, boiled on a hot plate, filtered and ignited in a 1000° C muffle furnace. It is cooled, weighed and recorded. The final weight is divided by the initial aliquot weight and % recovery is determined. The major and minor oxides from the ICP analysis are subtracted from the % recovered and the difference is Al<sub>2</sub>O<sub>3</sub>.

'''Equipment and Reagents'''

1. Glass beaker, 250 ml 

2. Nitric Acid (HNO<sub>3</sub>), trace metal grade

3. Deionized water, generated through reverse osmosis system

4. Ammonium Hydroxide (NH<sub>4</sub>OH), certified ACS Grade

5. Methyl red indicator (0.2 gram) dissolved in 100 ml 95% ethanol

6. Filter paper, rapid filtering, #41 or equivalent

7. Graphite crucibles, 8 ml capacity

8. Clear plastic beaker (polypropylene), 400 ml capacity

9. Magnetic stir bar, length of bar should be 1/2" shorter than the inside diameter of the beaker

10. Lithium Meta-borate (LiBO<sub>2</sub>), reagent grade, anhydrous

11. Yttrium Stock Solution, 1000 ppm

12. Platinum crucible, 15 ml capacity

13. Filter funnel

14. Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), capable of internal standard correction.

15. Muffle furnace, 1000° C capability

'''Procedure.'''          Add 1/4 teaspoon of LiBO<sub>2</sub> to 2 graphite crucibles and using a test tube, with approximately the same inner diameter of the crucible, press down to make a bed at the bottom of the crucible. Weigh 0.1000 g +/- .0005 g into each graphite crucible and cover the sample with a 1/4 teaspoon of LiBO<sub>2</sub>. Using tongs, place crucibles into a pre-heated 1000° C muffle furnace for 30 minutes. Add 150 milliliters of 1:24 HNO<sub>3</sub> to a 400 ml capacity clear plastic Polypropylene beaker. After 30 minutes in muffle furnace, remove first graphite crucible and transfer the fused pellet into the 150 ml 1:24 HNO<sub>3</sub>. Remove second crucible and transfer the fused pellet into the same 150 ml 1:24 HNO<sub>3</sub>. Stir for at least 10 minutes and filter through a #41 filter paper into a 200 ml volumetric flask containing 1 ml yttrium. Dilute to volume.

Analyze on the ICP-OES for SiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, P<sub>2</sub>O<sub>5</sub> and TiO<sub>2</sub> using the aggregate test template set-up with applicable calibration standards. Other oxides such as Ca, Mg, Na, K, Zn, Mn, Ba, Sr and Cr will also be determined during the run.

Take a 50 ml aliquot (0.05 gram) from the 200 ml volumetric flask and transfer to a 250 ml beaker. Add 3 drops of methyl red indictor solution. Add NH<sub>4</sub>OH drop-wise to the beaker until the solution turns yellow. Place watch glass over beaker and boil on hot plate for 60 seconds and let precipitate settle for no more than 5 minutes. Si, Fe, Al, P and Ti will precipitate out of solution. Filter through a #40 filter and wash with hot 20 grams ammonium nitrate per 1 liter of deionized water. Wipe inside the beaker with a folded #40 filter paper and transfer to filter containing precipitates. Transfer to a pre-weighed platinum crucible and ignite to 1000° C for 2 hours. Remove the crucible, cool, weigh and record. Divide the final recovered weight against the initial weight (0.05 gram) and calculate % recovery. Subtract SiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, P<sub>2</sub>O<sub>5</sub>, TiO<sub>2</sub> and any other detected oxides (ICP-OES analysis) from recovered weight and this will yield the % Al<sub>2</sub>O<sub>3</sub> by difference.

Note: Make sure to run a QC standard concurrently with the sample to verify validity of results.


[[Category:106.3.2 Material Inspection Test Methods]]