A Testing Method and Application of Fracture Toughness of Glazed Ceramic Tiles

Abstract

The present invention discloses a test method and application for the fracture toughness of glazed ceramic tiles. The test method includes the following steps: S1: Preparation of the test sample: On the glazed surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 1; on the body surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 2; on the side surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 3; S2: Bending test: Place Specimen 1, Specimen 2, and Specimen 3 with the V-shaped groove facing downwards and centered on the mechanical testing machine respectively, and conduct a bending test to obtain the maximum load force value P at the fracture of the three specimens max ; S3: Calculate the fracture toughness of the glaze, the fracture toughness of the body, and the fracture toughness of the side of the ceramic tile. The test method of the present invention is simple and convenient for sample preparation and can accurately measure and evaluate the fracture toughness of ceramic tiles from multiple dimensions.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic mechanical property testing, and in particular to a testing method and application of the fracture toughness of glazed ceramic tiles. Background Art

[0002] Building ceramic tiles are ceramic products made of various inorganic non-metallic materials such as clay and natural minerals through molding, high-temperature calcination and other production processes. They have good physical properties, such as high temperature resistance, corrosion resistance, and high strength. According to the type, they can be divided into porcelain tiles, stoneware tiles, porcelain tiles, etc. Glazed tiles, polished tiles, marble tiles, mosaics, rock slabs, etc. on the market are all building ceramic tiles. Building ceramic tiles are brittle materials, and the breakage rate is high during mechanical processing such as cutting. This characteristic restricts the application of building ceramic tiles. Especially as a plate in furniture and home furnishings, it is often necessary to turn holes, chamfer, cut, etc. for building ceramic tiles, and catastrophic brittle fractures often lead to the scrapping of the entire tile. Therefore, how to accurately and quickly test the toughness of building ceramic tiles and evaluate their use as engineering materials is of great significance.

[0003] The pre-crack beam method can be used to evaluate the fracture toughness of fine ceramics, but the pre-crack beam method has specific size requirements for the test sample, usually with a width and thickness of only 3 to 4 mm. The thickness of common building ceramic brick materials is usually 6 mm, 9 mm, 12 mm or even 20 mm, which cannot meet the size requirements of sample testing. The pre-crack beam method requires the introduction of a thin and short crack on the surface of the sample to be tested, and the process of making pre-cracks is complicated and has a low success rate. In order to simulate natural cracks, straight-through cuts can be artificially introduced instead, but the width of the straight-through cut will significantly affect the measured value of fracture toughness. The larger the incision width, the easier it is to cause crack tip blunting, resulting in a larger measured value of fracture toughness, overestimating the toughness of the material, and unpredictable damage in practical applications.

[0004] In addition, unlike fine ceramics, architectural ceramic tiles usually have decorative glazes, and their properties are significantly different from those of the body, and there is also interfacial stress between the body and the glaze. The existing fracture toughness measurement method is only for unglazed fine ceramics. Obviously, the presence of glaze will seriously affect the fracture toughness test results of architectural ceramic tiles. In actual processing such as grooving, edging, hole turning, cutting, etc., the stress-bearing parts of architectural ceramic tiles are different, and the required toughness is also different. For architectural ceramic tiles with glaze, they should not be regarded as homogeneous ceramics, but as composite materials combined with body and glaze. If the fracture toughness is measured by simply preparing a straight-through notch or prefabricated crack in one direction, it is obviously biased.

[0005] So far, there is no accurate, reliable and easy-to-operate test method that can be applied to glazed architectural ceramic tiles. Summary of the Invention

[0006] In view of the problems existing in the background art, the present invention provides a test method and application for the fracture toughness of glazed ceramic tiles. The sample preparation of this method is simple, applicable to large-sized samples, and the fracture toughness of building ceramic tiles measured by this method has good repeatability, and can characterize the toughness of building ceramic tiles from multiple dimensions.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] On the one hand, the present invention provides a test method for the fracture toughness of glazed ceramic tiles, and the test method includes the following steps:

[0009] S1: Preparation of the sample to be tested:

[0010] On the glazed surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 1;

[0011] On the body surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 2;

[0012] On the side surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 3;

[0013] S2: Bending test:

[0014] Place Specimen 1, Specimen 2, and Specimen 3 with the V-shaped groove facing down and centered on the mechanical testing machine respectively, and conduct a bending test to obtain the maximum load force value P when the three specimens break max ;

[0015] S3: Calculate the fracture toughness of the glaze, the fracture toughness of the body, and the fracture toughness of the side of the ceramic tile according to the size of the sample to be tested and the maximum load force value P max

[0016] Furthermore, the width b of the V-shaped groove is less than 0.3 mm, and preferably, the width b of the V-shaped groove is less than 0.2 mm.

[0017] Furthermore, the depth a of the V-shaped groove of Specimen 1 is greater than the thickness T of the glaze g , and the ratio a / T of the groove depth a to the total thickness T of the ceramic tile is 20% - 80%.

[0018] Furthermore, the depth a of the V-shaped groove of Specimen 2 is less than the thickness T of the body b , and the ratio a / T of the groove depth a to the total thickness T of the ceramic tile is 20% - 80%.

[0019] Furthermore, the ratio a / W of the depth a of the V-shaped groove of Specimen 3 to the total width W of the ceramic tile is 20% - 80%.

[0020] Further, when performing the bending test, the loading rate of the mechanical testing machine is 0.2 mm / min to 10 mm / min.

[0021] Further, when performing the bending test, the length of the two ends of the sample to be tested exposed is not less than 10 mm.

[0022] On the other hand, the present invention also provides an application of the test method for the fracture toughness of glazed ceramic tiles, and the test method is used for building ceramic tiles or building ceramic plates.

[0023] Further, the building ceramic tiles include earthenware tiles, stoneware tiles, and porcelain tiles, and the building ceramic plates include sintered stone.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The test method for the fracture toughness of glazed ceramic tiles of the present invention is applicable to building ceramic tile / plate materials of various sizes and specifications. It is convenient to make samples without the need to process the glazed ceramic tiles into small-sized samples, and the original size is retained as much as possible, avoiding errors caused by sample processing.

[0026] (2) The test method for the fracture toughness of glazed ceramic tiles of the present invention takes into account the influence of the glaze layer on the surface decoration of building ceramic tiles on their fracture toughness. Measuring from multiple dimensions can comprehensively and effectively evaluate the fracture toughness of building ceramic tiles, avoiding limitations and deviations caused by preparing samples in a single direction.

[0027] (3) The test method for the fracture toughness of glazed ceramic tiles of the present invention is applicable to various building ceramic tile materials with glaze, and has a wide application range. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the sample preparation of the first glazed notch specimen;

[0029] Figure 2 It is a schematic diagram of the sample preparation of the second green body notch specimen;

[0030] Figure 3 It is a schematic diagram of the sample preparation of the third side notch specimen;

[0031] Figure 4 It is a schematic diagram of the three-point bending loading test; Detailed Embodiments

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In the present invention, it should also be noted that the terms "installation" and "connection" should be understood in a broad sense. For example, it can be fixedly connected, can also be detachably connected, can also be mechanically connected, can also be indirectly connected through an intermediate medium, and can also be electrically connected. The specific meaning of the terms in the present invention can be understood according to specific circumstances.

[0034] The present invention provides a method for testing the fracture toughness of glazed ceramic tiles, and the testing method includes the following steps:

[0035] S1: Preparation of samples to be tested:

[0036] On the glazed surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 1, as Figure 1 shown;

[0037] On the body surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 2, as Figure 2 shown;

[0038] On the side surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 3, as Figure 3 shown;

[0039] In order to improve the accuracy of the test results, the number of specimens to be tested made by each method is not less than 5, that is, the number of Specimen 1, Specimen 2, and Specimen 3 is greater than or equal to 5. Preferably, the number of specimens to be tested of each specification is 8 or more. As many sample numbers as possible are beneficial for statistics and ensure the accuracy and reliability of the overall test results.

[0040] It should be noted that the glazed ceramic tile includes a base body and a glaze on the upper surface of the base body, and the side surface is one side surface that penetrates the base body and the glaze. There are no special regulations on the length (L) and width (W) of the three test specimens, and only need to be processed to meet the test dimensions of the mechanical testing machine. The thickness (T) is maintained at the original thickness.

[0041] S2: Bending test:

[0042] Place Specimen 1, Specimen 2, and Specimen 3 with the V-groove facing down and centered on the mechanical testing machine respectively, and conduct a bending test to obtain the maximum load force value P at the fracture of the three specimens. max ;

[0043] S3: Calculate the fracture toughness of the glaze, the fracture toughness of the base body, and the fracture toughness of the side surface of the ceramic tile:

[0044] Calculate the fracture toughness of the glaze and the fracture toughness of the base body through Equation 1. The expression of Equation 1 is:

[0045]

[0046] Among them, K IC is the fracture toughness, with the unit of MPa·m 1 / 2 ; g is the shape factor, dimensionless, calculated from Equation 2; P max is the maximum load force value at the fracture of Specimen 1 or Specimen 2, with the unit of N; S0 is the span of the test sample, with the unit of mm; W is the width of the sample, with the unit of mm; T is the thickness of the sample, with the unit of mm; a is the depth of the V-groove, with the unit of mm;

[0047] The expression of Equation 2 is:

[0048]

[0049] Among them, T is the thickness of the sample, with the unit of mm; a is the depth of the V-groove, with the unit of mm;

[0050] It should be noted that measure the thickness T and the depth a of the V-groove of Specimen 1, substitute them into Equation 2 to obtain the value of the shape factor g, and then measure the maximum load force value P max , width W, span S0 of Specimen 1, and substitute the shape factor g, thickness T, and depth a of the V-groove into Equation 1 to obtain the fracture toughness of the glaze; measure the thickness T and the depth a of the V-groove of Specimen 2, substitute them into Equation 2 to obtain the value of the shape factor g, and then measure the maximum load force value P max , width W, span S0 of Specimen 2, and substitute the shape factor g, thickness T, and depth a of the V-groove into Equation 1 to obtain the fracture toughness of the base body.

[0051] The fracture toughness of the side of the ceramic tile is calculated by Equation 3, and the expression of Equation 3 is as follows:

[0052]

[0053] where K IC is the fracture toughness, with the unit of MPa·m 1 / 2 ; g is the shape factor, dimensionless, calculated by Equation 4; P max is the maximum load force value at the triple fracture of the specimen, with the unit of N; S0 is the span of the test sample, with the unit of mm; W is the width of the sample, with the unit of mm; T is the thickness of the sample, with the unit of mm; a is the depth of the V-groove, with the unit of mm;

[0054] The expression of Equation 4 is as follows:

[0055]

[0056] where W is the width of the sample, with the unit of mm; a is the depth of the V-groove, with the unit of mm.

[0057] Specifically, the width b of the V-groove is less than 0.3 mm, and preferably, the width b of the V-groove is less than 0.1 mm.

[0058] It should be noted that the width W and the V-groove depth a of Specimen III are measured, substituted into Equation 4 to obtain the value of the shape factor g, and then the maximum load force value P max of Specimen III, the thickness T, and the span S0 are measured, and the shape factor g, the width W, and the V-groove depth a are substituted into Equation 3, then the fracture toughness of the side of the ceramic tile can be obtained.

[0059] Specifically, the V-groove depth a of Specimen I is greater than the thickness of the glaze layer (T g , thickness of glaze), that is, the incision needs to completely cut through the glaze layer, and the ratio of the groove depth a to the total thickness T of the ceramic tile, a / T, is 20% - 80%, and preferably, a / T is 30% - 50%.

[0060] Specifically, the V-groove depth a of Specimen II is less than the thickness of the green body (T b , thickness of body), a < T b , that is, the incision cannot cut through the green body, and the ratio of the groove depth a to the total thickness T of the ceramic tile, a / T, is 20% - 80%, and preferably, a / T is 30% - 50%.

[0061] Specifically, the ratio of the V-groove depth a to the total width W of the ceramic tile for Specimen III, a / W, is 20% - 80%, and preferably, a / W is 30% - 50%.

[0062] Specifically, the processed sample to be tested is subjected to a three-point bending load test on a mechanical testing machine. The part with the V-groove is in the middle, and the V-groove faces downward. See Appendix Figure 4 After adjusting the span, ensure that the length of the two free ends exposed is not less than 10 mm. Apply a load on the specimen for a bending test at a loading rate of 0.2 mm / min to 10 mm / min until the specimen to be tested breaks, and then obtain the maximum load force value P when the three specimens break max .

[0063] Since the size specifications of building ceramic tiles are generally large, larger sizes can be used when making test samples to meet the conditions and reduce the sample deviation caused by cutting specimen processing. A flat grinding wheel cutting machine, a water jet, or a diamond wire cutting can be used to cut the building ceramic tile into the required size of the sample to be tested. The thickness of the sample to be tested should be kept as consistent as possible to reduce errors.

[0064] The purpose of grooving the sample is to simulate natural cracks and introduce a notch on the sample. The sample will break along this place during subsequent tests. The smaller the width of the groove, the more accurate the measurement result. For building ceramic glazed tiles, if the width of the groove is greater than 0.3 mm, it will cause obvious crack blunting, that is, the groove is not sufficient to fully induce stress concentration, resulting in a larger measured fracture toughness value.

[0065] Cutting V-grooves from different surfaces is to comprehensively evaluate the performance of glazed building ceramic tiles in resisting crack propagation under the action of forces on different surfaces. The presence of the body-glaze layer of building ceramic tiles has a great influence on the fracture toughness of building ceramic tiles. Therefore, when grooving from the glaze surface, the glaze layer needs to be completely removed, and the actually measured fracture toughness is that of the body layer, which is suitable for judging the toughness of ceramic tile grooving processing. When grooving from the body surface, the depth of the groove needs to be strictly limited within the body thickness, that is, a < T b , and the measured fracture toughness is that of the remaining body and glaze. When grooving from the side surface, both the body and the glaze are cut off, and the ratio of the remaining body bottom and glaze layer is the same as the original, and the measured fracture toughness is suitable for the cutting processing of ceramic tiles.

[0066] It should be noted that the fracture toughness values of the three sample preparation methods can be obtained by using the test method of the present invention, that is, the fracture toughness of the standard glazed ceramic tile is comprehensively evaluated by the glaze surface fracture toughness, the body fracture toughness, and the side fracture toughness, which is beneficial for users to better understand the performance of building ceramic tile materials. The minimum value of the three data can also be used as the fracture toughness of the building ceramic tile to improve the safety factor.

[0067] The fracture toughness test method for glazed ceramic tiles provided by the present invention can be used for various building ceramic tile / plate materials including but not limited to ceramic tiles, stoneware tiles, porcelain tiles, and rock slabs.

[0068] Example 1

[0069] This embodiment discloses a test method for the fracture toughness of glazed ceramic tiles, including the following steps:

[0070] (1) Cut 30 splines from a building ceramic tile with a specification of width 800 mm × length 800 mm × thickness 10 mm. The size specification is: width 20 mm × length 70 mm × thickness 10 mm. Then divide them into three groups, with 10 splines in each group, and prepare V-shaped straight-through notches using a diamond wire cutting machine;

[0071] Specifically, for the first type of glazed cut spline, at the position of 400 mm in length, along the width direction, cut a groove with a depth of 3 mm and a width of 0.15 mm from the glazed surface to obtain Specimen I; for the second type of body cut spline, at the position of 400 mm in length, along the width direction, cut a groove with a depth of 3 mm and a width of 0.15 mm from the body to obtain Specimen II; for the third type of body cut spline, at the position of 400 mm in length, along the width direction, cut a groove with a depth of 6 mm and a width of 0.15 mm from the side to obtain Specimen III.

[0072] (2) Place the V-shaped notches of these three groups of specimens downward on the three-point bending fixture of a universal testing machine, set the span S0 to 50 mm, and the loading speed to 0.5 mm / min, and measure the maximum load P of the three-point bending max ;

[0073] (3) Calculate the fracture toughness values K IC (glaze), K IC (body), and K IC (side) obtained by the three sample preparation methods of glazed cut, body cut, and side cut according to Formulas 1 - 4 respectively, which are 0.587 MPa·m 1 / 2 , 0.702 MPa·m 1 / 2 , and 0.821 MPa·m 1 / 2 .

[0074] Example 2

[0075] This embodiment discloses a test method for the fracture toughness of glazed ceramic tiles, including the following steps:

[0076] (1) Cut three types of splines from a building ceramic tile with a specification of width 600 mm × length 600 mm × thickness 20 mm:

[0077] The dimensional specifications of the first type of spline are: width 20 mm × length 70 mm × thickness 20 mm. Then, starting from the glazed surface at the 300 mm position along the length, a V-groove with a width of 0.2 mm is cut along the width direction using a diamond wire saw. The ratios of the depth a of the V-groove to the thickness T are 20%, 30%, 40%, 50%, 60%, and 70% respectively, and the number of specimens for each group of a / T is 8;

[0078] The dimensional specifications of the second type of spline are: width 20 mm × length 70 mm × thickness 20 mm. Then, starting from the green body at the 300 mm position along the length, a V-groove with a width of 0.2 mm is cut along the width direction. The ratios of the depth a of the V-groove to the thickness T are 20%, 30%, 40%, 50%, 60%, and 70% respectively, and the number of specimens for each group of a / T is 8;

[0079] The dimensional specifications of the third type of spline are: width 20 mm × length 70 mm × thickness 20 mm. Then, starting from the glazed surface at the 300 mm position along the side direction, a V-groove with a width of 0.2 mm is cut. The ratios of the depth a of the V-groove to the width W are 20%, 30%, 40%, 50%, 60%, and 70% respectively, and the number of specimens for each group of a / T is 8.

[0080] (2) Place the notched sides of these three groups of specimens downward on the three-point bending fixture of a universal testing machine. Set the span S0 to 50 mm and the loading speed to 5.0 mm / min, and measure the maximum load P of the three-point bending. max .

[0081] (3) Calculate the fracture toughness values K IC (glaze), K IC (green body), and K IC (side) obtained by the three sample preparation methods of glaze cutting, green body cutting, and side cutting respectively according to Formulas 1 - 4. The mean results of the fracture toughness measured at different notch depths are shown in Table 1 below.

[0082] Table 1 Fracture toughness values measured by glaze cutting, green body cutting, and side cutting at different notch depth ratios

[0083]

[0084] Example 3

[0085] This example discloses a test method for the fracture toughness of glazed ceramic tiles, including the following steps:

[0086] (1) Cut out splines of various different specifications from a building ceramic tile with a specification of width 1200 mm × length 2600 mm × thickness 6 mm. At the mid - length position, use a diamond wire saw to cut a V - groove with a width of 0.15 mm along the width direction according to the sample preparation methods for the glaze surface, the body, or the side. Ensure that the ratio of the depth a of the V - groove to the thickness T or the width W is maintained at 40%. The number of specimens in each group is 8.

[0087] (2) Place the specimens with the groove mouths facing down on the three - point bending fixture of a universal testing machine. Set the corresponding span S0, and the loading speed is 1.0 mm / min. Measure the maximum load P of the three - point bending. max . Calculate the fracture toughness values K IC (glaze), K IC (body), and K IC (side) obtained by the three sample preparation methods of glaze cutting, body cutting, and side cutting respectively according to Formulas 1 - 4. The mean results of the obtained fracture toughness are shown in Table 2 below.

[0088] Table 2 Fracture toughness values measured for splines of different specifications at a cut - depth ratio of 40%

[0089]

[0090]

[0091] Example 4

[0092] This embodiment discloses a test method for the fracture toughness of glazed ceramic tiles, including the following steps:

[0093] Cut out splines with a specification of width 20 mm × length 70 mm × thickness 9 mm from a building ceramic tile with a specification of width 800 mm × length 800 mm × thickness 9 mm; from the glaze surface of the sample at the 35 - mm position along the length, use a marble cutting machine, a slow cutting machine, a diamond wire saw, an ultraviolet laser, etc. to cut grooves of different widths along the width direction. The ratio of the depth a of the groove to the thickness T is maintained at 40%. The number of specimens in each group is 9. Then place the specimens with the groove mouths facing down on the three - point bending fixture of a universal testing machine, set the span S0 to 50 mm, and the loading speed is 5.0 mm / min. Measure the maximum load P of the three - point bending. max . Calculate the fracture toughness value K IC obtained by the glaze - cutting sample preparation according to Formulas 1 and 2. The results are shown in Table 3.

[0094] It can be seen that the width of the cut groove has an obvious influence on the measured value of the fracture toughness. When the width of the cut groove exceeds 0.3 mm, the larger the width, the larger the measured fracture toughness value, that is, an obvious crack - blunting effect appears.

[0095] Table 3 Fracture toughness values of splines with different grooving widths measured at a cutting depth ratio of 40%

[0096]

[0097]

[0098] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0099] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A test method for the fracture toughness of glazed ceramic tiles, characterized in that, The test method comprises the following steps: S1: Preparation of the sample to be tested: On the glazed surface of a rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 1; the width b of the V-shaped groove is less than 0.3 mm, and the depth a of the V-shaped groove is greater than the thickness T of the glazed surface g , and the ratio a / T of the groove depth a to the total thickness T of the ceramic tile is 20% to 80%; On the green body surface of the rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen 2; the width b of the V-shaped groove is less than 0.3 mm, and the depth a of the V-shaped groove is less than the thickness T of the green body b , and the ratio a / T of the groove depth a to the total thickness T of the ceramic tile is 20% to 80%; On the side surface of a rectangular ceramic tile, a V-shaped groove is machined at the middle position perpendicular to the length direction to obtain Specimen III; the width b of the V-shaped groove is less than 0.3 mm, and the ratio a / W of the depth a of the V-shaped groove to the total width W of the ceramic tile is 20% to 80%; S2: Bending test: Place Specimen 1, Specimen 2, and Specimen 3 with their V-grooves facing down and centered on the mechanical testing machine for a bending test to obtain the maximum load force value P at the fracture of the three specimens. max ; S3: Calculating the fracture toughness of the glaze, the fracture toughness of the body and the fracture toughness of the side surface of the ceramic tile: The fracture toughness of the glaze and the fracture toughness of the body are calculated by Equation 1, The expression of Formula 1 is as follows: where K IC is the fracture toughness in MPa·m 1 / 2 ; g is the shape factor, dimensionless, calculated from Equation 2; P max is the maximum load value at fracture of Specimen 1 or Specimen 2 in N; S o is the span of the test sample in mm; W is the width of the sample in mm; T is the thickness of the sample in mm; a is the depth of the V-notch in mm; The expression of Formula 2 is as follows: where T is the thickness of the sample in mm; a is the depth of the V-shaped groove in mm; The fracture toughness of the side surface of the ceramic tile is calculated by Equation 3, The expression of Formula 3 is: Among them, K IC is the fracture toughness, with the unit of MPa·m 1 / 2 ; g is the shape factor, dimensionless, calculated by Equation 4; P max is the maximum load force value at the triple fracture of the specimen, with the unit of N; S o is the span of the test sample, with the unit of mm; W is the width of the sample, with the unit of mm; T is the thickness of the sample, with the unit of mm; a is the depth of the V-groove, with the unit of mm; The expression of Formula 4 is as follows: where W is the width of the sample in mm; a is the depth of the V-shaped groove in mm.

2. The test method for the fracture toughness of the glazed ceramic tile according to claim 1, wherein When performing the bending test, the loading rate of the mechanical testing machine is 0.2 mm / min to 10 mm / min.

3. The test method for the fracture toughness of the glazed ceramic tile according to claim 1, wherein, When performing the bending test, the length of the two ends of the sample to be tested exposed is not less than 10 mm.

4. Use of the method for testing the fracture toughness of the glazed ceramic tile according to any one of claims 1 to 3, characterized in that, The test method is used for building ceramic tiles or building ceramic plates.

5. Use of the method for testing the fracture toughness of glazed ceramic tiles according to claim 4, characterized in that, The building ceramic tiles include earthenware tiles, stoneware tiles, and porcelain tiles, and the building ceramic plates include sintered stone.

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