ASTM D7098 Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B
6. Apparatus
6.1 Oxidation Bath and Pressure Vessel - See appropriate Annex (Annex A1 or Annex A2) for detailed description of apparatus and accessories for equipment described in this test method.
NOTE 1 - To reduce vapor odors when opening pressure vessel after use, a hood may be desirable.
6.2 Precision Pressure Gauge - Use a certified precision pressure gauge to accurately control the oxygen feed to the pressure vessel. The gauge shall have a sufficient range to encompass 0 to 650 kPa (~90 psig) required by the test method with division 2.0 kPa (~0.5 psig) or better to enable readings to be made to 2.0 kPa (~0.25 psig).
7. Reagents
7.1 Purity of Reagents - Reagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents ofthe American Chemical Society.
7.2 Purity of Water - Unless otherwise indicated, references to reagent water shall be understood to mean distilled water meeting requirements of reagent water as defined by Type I of Specification D1193.
7.3 Acetone, CH3COCH3.
7.4 Air, containing 2000 ppm nitrogen dioxide, NO2 (commercially available compressed gas mixture, certified within +/- 5 %).
7.5 Cyclo-hexane, C6H12, Practical Grade or other suitable hydrocarbon solvent. (Warning - Highly flammable. Skin irritant on repeated contact. Aspiration hazard.)
7.6 Isopropyl Alcohol, CH3CH(CH3)OH.
7.7 Oxygen, 99.8 %.
8. Materials
8.1 TFOUT Catalyst B Package:
8.1.1 Fuel Component - The fuel component is a nitrated gasoline fraction or organic equivalent. This component may be prepared in accordance with the procedures described in Annex A3.
8.1.2 Soluble Metal Catalyst Mixture - This catalyst is a mixture of soluble metal catalysts (lead, iron, manganese, and tin). The catalyst may be prepared according to the procedures described in Annex A4.
8.1.2.1 Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies may be inconsistent and have significant effects on the test results. Thus, for test comparisons, the same source and same batch of metal naphthenates shall be used.
NOTE 2 - It is good research practice to use the same batches of catalyst components when closely comparing engine oils.
NOTE 3 - Slow, steady reactivity of some of the catalyst chemicals can be a problem. Such problems can be reduced by storing the closed catalyst vials in a refrigerator at approximately 5°C. The catalyst chemicals remain effective up to six months after the septum is punctured, if they are stored as noted above.
8.1.3 Nitro-paraffın - This compound is made up of a nitrialkane blend.
NOTE 4 - Suitably prepared catalyst packages may be purchased from the market.
8.2 Varnish and Deposit Remover, water-soluble varnish remover or other engine varnish/deposit removers.
8.3 Silicone Stopcock Grease.
