1、FORD LABORATORY TEST METHOD BP 106-04 Date 2001 0823 1990 02 23 ELASTOMERIC MATERIALS MOUNTING FOR MICROHARDNESS TEST Action Revisions Revised Editorial - no technical change A. Cockman Application This test method describes techniques for mounting small rubber components and materials in preparatio
2、n for determining microhardness (IRHD) according to ASTM D 1415. It describes sample preparation and mounting procedures to assure minimal movement when a “hold-down“ mechanism is not practical during the measurement of irregularly-shaped finished elastomeric parts such as “lip“ seals or other compo
3、nents with concave or convex surfaces. Apparatus Required Surgical Blades and Handle An alternative consists of a hand-held fixture in which parallel single-edge razor blades are mounted at 2 mm distance. Tweezers Bench clamp or laboratory vise. Polishing Surface Such as a marble or epoxy table top.
4、 Pocket Kn fe Materials Required Emery Paper 400 - 600 grit. Steel Discs Parallel surfaces and fine-ground; 40 mm dia x 5 mm thick. Cutting Surface Wood, leather, or dense cardboard (e.g., posterboard). Tissues Laboratory grade, lint-free. Copynght02001, Ford Global Technologies, Inc FORD LABORATORY
5、 TEST METHOD BP 106-04 Ethanol Reagent grade: CAUTION: FLAMMABLE. Cyanoacrylate Adhesive Epoxy Adhesive Room temperature (23 +/- 2 OC) cure (2-part). Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 OC and 50 +
6、/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure Specimen Preparation: 1. Using a handle-mounted, sharp surgical blade upon a wood, leather, or dense cardboard cutting surface, cut the elastomeric samples cons
7、istent with the minimum dimensions stated in ASTM D 1415. Assure that the sections are smooth and that the surface in which measurements will be taken is parallel to the surface to be used for bonding. Bonding Non-Volatile Fluid Aged or Unaged Specimens Using Cyanoacrylates: 1. Wipe the mounting dis
8、c with alcohol and tissue to remove all detectable traces of contaminants. 2. Carefully apply a drop of cyanoacrylate adhesive or several separate drops if several specimens are to be mounted on one disc at a time. Note: Observe the precautions regarding the use of cyanoacrylate. This adhesive rapid
9、ly bonds human tissue. 3. Using tweezers, place the specimen on the adhesive drop and gently press with the flat edge of a scalpel or tweezers to assure intimate contact with the steel disc. Avoid excessive pressure which may cause rubber deformation and bonding in a stressed condition which may aff
10、ect the hardness measurement. 4. To hasten the adhesive curing, carefully “wick“ any excess adhesive with the corner of a tissue while maintaining gentle pressure on the specimen for 1 - 2 minutes. Ensure that adhesive does not contact the surface to be checked for hardness as it becomes brittle whe
11、n dry and must be scraped away. Page 2 of 3 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BP 106-04 5. Ensure that a good bond has been achieved by applying gentle pressure on the specimen in a shear direction. This is particularly important for rubber materials that have
12、seen oil or fuel service or are prelubricated. Oils and fuels can migrate to the surface during specimen mounting and interfere with the bonding. Alternative Procedure Using Epoxy to Imbed Specimens Exposed to Fluids That Preclude Adequate Bonding: Note: In the event Cyanoacrylates are unsatisfactor
13、y, a room temperature (23 +/- 2 OC), two-part epoxy has been found useful because its greater viscosity allows the specimen to be imbedded rather than adhered on one surface. 1. Use sufficient epoxy to submerge almost the specimen leaving only the top surface uncovered to permit hardness measurement
14、s. 2. Test the epoxy surface by indenting to determine whether it is sufficiently rigid to immobilize the specimen. 3. If the fuel-aged specimens have begun to “flash-off during the epoxy-hardening process, thereby invalidating the hardness measurements, immerse the entire disc with the imbedded spe
15、cimen for a short time in a container of fuel to “reconstitute“ the specimen volume and hardness. The duration of the immersion will depend on the aromaticity of the fuel and the polymer being evaluated. Conditions making such action necessary, as well as immersion times, fuel to be used, etc., must
16、 be agreed between Ford Motor Company and the supplier before carrying out this procedure. Removal of Tested Specimens: 1. Secure the disc in a clamp or vise and force the blade of a sturdy pocket knife beneath the adhesive. Note: Safety glasses should be worn owing to the risks encountered when bri
17、ttle epoxy material, a knife, or a scalpel blade shatters. 2. Scrape the disc with the scalpel blade to remove as much adhesive as practical. 3. Remove the disc from the clamp or vise, invert, and polish it on 400 grit and then 600 grit abrasive paper. The abrasive paper should lie flat on a true su
18、rface. 4 Lightly oil to prevent rust during subsequent storage. Note: Periodically have the disc checked to assure that the buffing has not introduced curvature that can cause slight “rocking“ while taking hardness measurements which can cause erroneous results. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. Page 3 of 3 Copynght02001, Ford Global Technologies, Inc
