ISO 20509:2003 pdf download

ISO 20509:2003 pdf download.Fine ceramics (advanced ceramics,advanced technical ceramics)一 Determination of oxidation resistance ofnon-oxide monolithic ceramics.
4.5 Testing fixture for flexural strength, of three- or four-point flexure configuration in accordance with 5.2 of ISO 14704:2000. The recommended fixture is fully articulated and of the four-point-i /4 point configuration with the two outer bearings at a distance of 40 mm. The corresponding total length of test piece is 45 mm.
4.6 Micrometer, such as shown in ISO 3611:1978 but with a resolution of 0,002 mm for measuring the test piece dimensions. The micrometer shall have flat anvil faces such as shown in ISO 3611:1978. The micrometer shall not have a ball tip or sharp tip since these might damage the test piece. Alternative dimension measuring instruments may be used provided that they have a resolution of 0,002 mm or finer.
4.7 Vernier calliper, with a resolution of 0,05 mm or finer for measuring the length of the test piece, in
accordance with ISO 6906. Alternative dimension measuring instruments may be used provided that they have
a resolution of 0,05 mm or finer.
4.8 Balance, capable of weighing up to 200 g with a sensitivity of at least 0,05 mg.
4.9 Thermocouple, of type R or type S in accordance with IEC 60584-2, permitting the use of the calibration
table given in lEO 60584-i.
5 Test pieces
If the strength changes are to be determined, flexural strength test pieces in accordance with Clause 6 of ISO 14704:2000 shall be used. The standard test specimens shall have cross-sectional dimensions of 3,00 mm + 0,20 mm thickness and 4,00 mm ± 0,20 mm width. The length shall be more than 35 mm for
30 mm test fixtures or more than 45 mm for 40 mm test fixtures. All the surfaces shall be machined, and edges shall be rounded or chamfered. Any machining procedure and the surface quality of the test pieces shall be reported. The minimum number of test pieces shall be 10 for each oxidation condition to be tested, plus 10 test pieces as an unoxidized control. Means shall be taken to identify individually, similar test pieces, but shall not be marked or scribed in a way that might affect the result of the test. If strength changes are not to be determined, any test piece, in terms of size and shape, may be used.
Test pieces shall be clean and free from preparation residues and contamination due to handling which can influence the initial mass measurement and/or the oxidation rate. The test-piece cleaning procedure shall be stated in the report.
For materials with no significant open porosity and contaminated by handling, and/or by mounting or machining coolant residues, submerge the test-pieces in ethanol in an ultrasonic bath and agitate for at least 10 mm. In order to avoid damage, test pieces shall not be allowed to contact either each other or a hard surface during this operation. For materials containing open porosity, internally entrained organic residues can be removed only by heating in air. The maximum temperature to which this should be done will depend on the material type, but typically a temperature of 500 °C to 600 °C for a least 1 h is required to oxidize carbonaceous residues. Material with intentionally present free carbon shall be treated at a maximum temperature of 350 °C to avoid. oxidation.
6 Test procedure
6.1 Measurements of dimensions and mass of specimens
For flexural strength test pieces, measure the width, b, and thickness, h, of each test piece at several places using the micrometer (4.5) with a resolution of 0,002 mm. Measure the overall length, LT, with the vernier callipers (4.6) with a resolution of 0,05 mm. For other shapes of test piece, measure relevant dimensions at several different places (e.g. diameter and thickness of a disc). Wash and degrease the test pieces (see Clause 5). Place in the oven (4.3) and heat to a temperature of 105°C to 120°C until their mass is constant. Remove and store in a desiccator. When cooled to room temperature, weigh each test piece to the nearest 0,05 mg using the balance (4.7). Store in the desiccator until tested.