Effects and strengthening mechanism of ion exchange treatment on mechanical properties of building ceramics
The strength of building ceramic tiles is of great significance in improving the service life of decorative materials and energy conservation and environmental protection.Ion exchange treatment can effectively improve the fracture resistance and flexural strength of ceramics by enhancing the surface extrusion stress.The two key factors affecting the ceramic strengthening process are ion-exchange temperature and ion-exchange time.In this paper,KNO3 molten salt is used to strengthen the mechanical properties of building ceramic plates.The effects of ion-exchange temperature and ion-exchange time on the mechanical properties of ceramics are analyzed,and the strengthening mechanism is further discussed.The results show that the flexural strength,fracture toughness and surface hardness are greatly improved after ion exchange treatment,while the elastic modulus and mass density are almost unchanged.By ion exchange treatment,preload compressive stress is formed on the ceramic surface through the displacement reaction between K+ of KNO3 molten salt and Na+ of the ceramic surface to offset part of the destructive loads.Under the ion exchange process at 600℃for 20h,the flexural strength of the ceramic sample reaches the maximum of 216.10MPa,which is 103.20%higher than that of the original sample.
building ceramicsion exchangechemical temperingcompressive stress layerstrengthening mechanism
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