How to identify wear-resisting ceramics

1. See the appearance

Identify the merits of the wear-resisting ceramics from appearance to identify the most simple and intuitive methods, high-quality wear-resistant ceramic surface smooth, no obvious flaws, the edge fully, colour and lustre is sleek look into light and crystal luster.Bad wear-resisting ceramics material is more, rough surface, color dim.

Bad wear-resisting ceramics

Good wear-resisting ceramics

2. The performance measurement indicators

1) density: the product with high density means high alumina content, at the same time also means that the structure is compact, so the density is the most simple and direct method.But completely by density index is difficult to judge the ceramics quality advantages and disadvantages, and with the help of other means.

2) the Al2O3 content: generally speaking, the content of Al2O3 on the wear resistance of products has had a huge impact, the higher the Al2O3 content, resistance to wear, the better.

3) hardness: hardness is considerations products one of the important indexes of abrasion resistance, especially under special circumstances will play a critical role, such as high speed low Angle of erosion wear particles.

4) toughness is the present study most frequently and most close relations with wear is also internal factors.People are now common understanding is great toughness and wear resistant ceramic relations of friction and wear.At present there are several ways to improve the fracture toughness of alumina ceramics:

(1) the particle dispersion toughening;

(2) fiber and must be toughening;

(3) zirconia phase transformation toughening,

(4) composite toughening;

(5) the toughening and so on.Fine city the use of independent research and development and whisker toughening is comparatively mature technology, ceramic toughness can be improved more than 1 times.Whisker itself has good mechanical properties, when whisker pulled up and fracture, consumes a certain amount of energy, to prevent the expansion of the crack.In addition, in the ceramic whisker of crack bridging, pinning or deflection can significantly increase the toughness of alumina ceramics.

This after toughening of alumina ceramics is widely used in impact wear parts.

Fracture toughness and hardness of the ceramic is regarded as the most important performance impact abrasion resistance.On the one hand, the performance depends on the microstructure characteristics, on the other hand is also related to the damage mechanism of the ceramics.So choose high-performance wear-resisting ceramics must pay special attention to the hardness and fracture toughness of the two indicators for evaluation.

3. Observe the crystallite structure

Wear-resisting ceramics, evaluation and selection should be all related to the wear resistance properties, microscopic structure and the working conditions as a whole to consider.For brittle Al2O3 material wear is due to the small abrasive dust particles into the friction surfaces and ceramic surface crack formation.When abrasive dust particles contact with Al2O3, in the "primary" elastic state, it will promote the formation of cracks, the radial and transverse crack wrinkle.In Al2O3 ceramic microstructure, corundum crystal boundary layer around the tiny crystal glass phase) (with the crack will begin from the boundary layer, the remnants of a micro cracks and other defects formed in the manufacturing process of formation of "stress concentration", thus forming the reticular cracks.Under the effect of wear debris particles continuously, the boundary layer begins to be destroyed and cause grain fall off.So the bonding strength of glass phase will directly affect the wear resistance of Al2O3 ceramics.

Some scholars have done on the relationship between the porosity and the friction and wear a detailed study, results: the surface when the porosity is not too big to the influence of the friction and wear is not big, and further increase the porosity, wear rate increases quickly.Dopant intervention would cause high temperature ceramic performance degradation, which affect the wear resistance of ceramics.And improve the grain boundary phase composition, structure and properties of ceramic fracture of wear resistance is improved greatly