As a special industrial ceramic, zirconia ceramics are used in various fields, and the feedback on its quality and performance is also very good. Before the application of zirconia ceramic materials, the first thing to do is to test its performance quality to ensure that all aspects can meet the standard specifications and put into use in a qualified state.

In the quality inspection of zirconia ceramic materials, the specific content of the inspection includes the dielectric constant of the substrate, the material, the drop of the steel ball, the hardness of the pencil, the substrate, the four-point bending strength, etc., the test methods of different parameters are also different, and the standard basis should be used as a reference.

First of all, as a qualified zirconia ceramic material, its substrate dielectric constant should be greater than 30; The steel ball drop is to use 20g steel ball at a height of 50cm to fall to the center of the ceramic with a diameter of 10mm, the ceramic material is placed on the rigid flat marble, and after three times of the same operation to ensure that no cracks appear in the ceramic sheet.

Secondly, the pencil hardness of zirconia ceramic material specified in the standard should be ≥8H; The specific test method is 750gf pressure, the Angle between the pencil lead and the surface to be measured is 45°, and 5 strokes are drawn on the position to be measured, each stroke is 10mm long, and no indentation is allowed on the surface.

At the same time, the cutting edge of the zirconia ceramic substrate is required to be sharp, the depth of the collapse is less than 0.03mm, and the surface must not appear pits, impurities, cracks, scratches and other defects. In addition, its four-point bending strength ≥500MPa; Its test method is, the upper span: 20mm, the lower span: 40mm, the pressure rod diameter is ￠6, the pressure speed is 10mm/min, and the pressure is lowered until the oxidized ceramic material is broken.

Detection of grain size distribution

The grain size distribution of zirconia ceramics is an important index to characterize its physical properties and processes. Common detection methods include field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD).

Among them, FE-SEM and TEM are electron beam-based microscopy techniques, which can be used to observe the morphology and crystal structure of materials, and can obtain more accurate grain size distribution. XRD is a method used to analyze the crystal structure of materials, and the crystal size and crystal defect information can be obtained by studying the position, shape, strength and width of the diffraction peak.

The detection of bending strength

The bending strength of zirconia ceramics is an important parameter to characterize its mechanical properties. Common detection methods include three point bending test and indentation method.

Three point bending test is to place the sample between two support points, and then apply a load to the middle to determine the bending strength of the sample. This method is simple and intuitive, but limited by the distance of fulcrum, it is not suitable for large samples.

The indentation method is to apply pressure to the surface of the sample and calculate the bending strength of the sample by observing parameters such as the length and width of the trace. This method can be applied to samples of different shapes and sizes, but it is not suitable for testing in high temperature and high pressure environments.

Hardness detection

The hardness of zirconia ceramics is an important parameter to characterize its wear resistance and scratch resistance. Commonly used testing methods include Vickers hardness, Rockwell hardness and indentation hardness.

Vickers hardness is to put the sample on the hardness tester, with a steel ball or diamond cone head for pressure test, to determine its surface hardness. Rockwell hardness is calculated by making a scratch on the surface of the sample and measuring the length and depth of the scratch. Indentation hardness refers to the application of a load on the surface of the sample to create an indentation, and the indentation length and width are used to calculate the hardness.