GB/T 8489-2006Test method for compressive strength of fine ceramics (advanced ceramics, advanced technical ceramics) (English PDF)

Foreword

This standard adopts the Japanese standard JIS R 1608-2003 "Testing methods for compressive strength of fine ceramics" with modifications.

This standard is a revision of GB/T 8489-1987 "Testing method for compressive (crushing) strength of high performance ceramics".

The main differences between this standard and JIS R 1608-2003 are as follows:

- CHANGE "high-performance ceramics" to "fine ceramics"; ADD the "functional ceramics" to the scope of application (see Chapter 1).

- DELETE the "loading plate" from the Terms (see Chapter 3).

- ADD the specifications regarding the testing machine load range at the time of specimen fracture (see 4.1).

- ADD the specifications for the dimensions, roughness, hardness, parallelism of the upper and lower platens (see 4.2).

- ADD the specifications regarding the dimensions, roughness, hardness, parallelism, usage of contact blocks (see 4.3).

- ADD the specifications regarding the thickness and material of spacers (see 4.4).

- ADD the specifications for the accuracy of measuring instruments (see 4.5).

- ADD the sampling specifications, changing the number of specimens per set to 10 (see 5.1).

- ADD the instructions for the preparation of piezoelectric ceramic specimens (see

- ADD a schematic diagram of square prismatic specimens (see Figure 1).

- ADD a schematic diagram of a lower platen with an arc-shaped surface (see Figure

- CHANGE the crosshead displacement rate to 0.2 mm/min (see 6.3).

- ADD a test method for piezoelectric ceramics; DELETE the provision regarding the reuse of loading plates (see 6.4).

- ADD the formula for calculating the average value (see 7.2).

- DELETE the original test report content and REWRITE it (see Chapter 8).

- DELETE the original appendix; ADD the specifications for the rounding of numerical values (see Appendix A).

This standard replaces GB/T 8489-1987. The main changes compared to the previous version are as follows:

- CHANGE the title from "engineering ceramics" to "fine ceramics".

1031 regarding surface roughness parameters and their values (Chapter 2 of the 1987 edition; Chapter 2 of this edition).

definition of compressive strength, adding a definition for compressive failure (Chapter 3 of the 1987 edition; Chapter 3 of this edition).

parameters to facilitate testing; ADD schematic diagrams of the specimen and loading method (Chapter 5 of the 1987 edition; Chapter 5 of this edition).

- SPECIFY new specimen dimensions, which use smaller samples than the original

standard, based on the Japanese Industrial Standard JIS R 1608-2003 and actual practices in ceramic compression testing in China, to facilitate testing on standard universal testing machines (Clause 5.2 of the 1987 edition; Clause 5.2 of this edition).

- CHANGE the "Test procedure" to "Test method" (Chapter 6 of the 1987 edition;

Chapter 6 of this edition), adding two explanatory notes (Clauses 6.5 and 6.6 of this edition).

- ADD the formula for calculating the mean value (Clause 7.2 of this edition).

edition; Clause 7.3 of this edition).

- ADD basic requirements regarding the number of samples for statistical data analysis (see Clause 7.4).

- ADD the requirements to the test report, regarding specimen shape, material,

dimensions, surface roughness, preparation conditions (Chapter 8 of the 1987 edition; Chapter 8 of this edition).

Appendix A of this standard is normative.

This standard was proposed by the China Building Materials Industry Association.

This standard shall be under the jurisdiction of the National Technical Committee on Industrial Ceramics.

Drafting organizations of this standard: China Building Materials Academy; Shenzhen New Sansi Metrology Technology Co., Ltd.

Drafting personnel of this standard: Bao Yiwang, Cao Zengchen, Ma Juanrong, Qiu Tuo, Lei Qing'an, Zhou Liwei.

1 Scope

This standard specifies the equipment, specimens, test procedures, result processing for determining the compressive strength of fine ceramics.

This standard applies to the determination of the compressive strength of fine ceramics at room temperature; it also applies to the determination of the compressive strength of functional ceramics at room temperature.

2 Normative references

The provisions in following documents become the provisions of this Standard through reference in this Standard. For the dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this Standard; however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.

3 Terms and definitions

The following terms and definitions apply to this standard.

The maximum compressive stress at the moment of fracture, when the specimen is subjected to a uniform uniaxial compressive load.

The event during a compression test where the specimen fractures into two or more pieces, or the compressive load drops significantly.

4 Test equipment

4.1 Testing machine: A materials testing machine capable of providing a uniform, adjustable displacement rate, with a relative error of load indication not exceeding ±1%. The maximum force at the time of specimen crushing shall fall within 20% ~ 90% of the testing machine's load capacity range. 4.2 It shall use an upper platen without a spherical seat and a lower platen with a spherical seat for adjusting surface parallelism. The centerlines of the upper and lower platens shall coincide with the centerline of the machine frame; the lower platen shall bear positioning marks. 4.2.2 The diameter of the platens shall be greater than 60 mm; the thickness greater than 30 mm. The upper and lower platens shall be parallel to each other, with a parallelism error not exceeding 0.02 mm. 4.3 Contact blocks: Hard alloy blocks shall be used between the platens and the specimen. The contact blocks shall have a thickness greater than 20 mm and a diameter greater than 25 mm (square blocks of equivalent dimensions may also be used). The upper and lower surfaces of the contact blocks shall be flat and parallel to each other, with a parallelism error not exceeding 0.015 mm; the surface roughness (Ra) shall not exceed 0.80 μm, as specified in GB/T 1031. 4.4 Spacers: Polytetrafluoroethylene (PTFE) film with a thickness of 35 μm or graphite paper with a thickness of 60 μm ~ 100 μm shall be used. […]

5 Specimens

5.1 Sampling: Specimens shall be cut from the product to be tested or prepared directly according to the product's manufacturing process; they shall be free from visible damage or cracks. Each set shall consist of at least 10 specimens.

5.2 Specimen shape and dimensions: As shown in Figure 1, the specimens shall be cylindrical or square-prismatic (with a square cross-section). For cylindrical specimens, the base diameter shall be 5 mm ± 0.1 mm and the height 12.5 mm ± 0.1 mm. For square-prismatic specimens, the cross-section side length shall be 5 mm ± 0.1 mm and the height 12.5 mm ± 0.1 mm. For piezoelectric ceramics, the length along the polarization direction shall be 12.5 mm ± 0.1 mm; the electrode surfaces shall not be removed.

5.3 Specimen preparation: The top and bottom surfaces shall be ground flat and parallel to each other, with a parallelism error of no more than 0.01 mm and a perpendicularity error relative to the axis of no more than 0.01 mm. The edges of the top and bottom surfaces shall be beveled at 45° or rounded, with a depth of 0.1 mm ~ 0.2 mm. The surface roughness (Rz) of the specimen shall be no greater than 3.2 μm, in accordance with GB/T 1031.