ASTM D5187 Standard Test Method for Determination of Crystallite Size (Lc) of Calcined Petroleum Coke by X-Ray Diffraction
1. Scope
1.1 This test method covers the determination of the mean crystallite thickness of a representative, pulverized sample of calcined petroleum coke by interpretation of a X-ray diffraction pattern produced through conventional X-ray scanning techniques.
1.2 Calcined petroleum coke contains crystallites of different thicknesses. This test method covers the determination of the average thickness of all crystallites in the sample by empirical interpretation of the X-ray diffraction pattern. The crystallite diameter (La) is not determined by this test method.
1.3 The values stated in SI (metric) units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information purposes only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D346 Practice for Collection and Preparation of Coke Samples for Laboratory Analysis
D2013 Method for Preparing Coal Samples for Analysis
D2234 Test Methods for Collection of a Gross Sample of Coal
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 crystallites - stacks of graphitic carbon platelets located parallel to one another.
3.1.2 Lc - the mean or average thickness of crystallites in a sample. It is expressed as a linear dimension in angstrom units, Å (10(−1) nm).
3.1.3 hkl(002) - the Miller indices of the crystalline planes of graphite corresponding to a lattice spacing (d) of 3.35 Å.
3.1.4 Ⓗ - the glancing angle produced when a parallel beam of uniform X-rays impinges upon a crystalline lattice. This angle is measured by the X-ray goniometer and is usually expressed in °2Ⓗ.
