The Effect Of Alloying Elements On The Wettability Of Zta/High Chromium Cast Iron Interface

ZTA(zirconia toughened alumina ceramic)/high chromium cast iron composite materials are widely used as wear-resistant parts such as vertical mills and impact crushers in large-scale equipment.Due to the large difference in physical and chemical properties between the ceramic phase and the metal phase,the wettability of the two particularly poor,so the interface bonding strength of the composite material is very weak.Under the action of external force,cracks are easily generated at the interface and fracture failure occurs.Therefore,in this paper,Al2O3 and ZrO2 ceramic powders are doped with alloying elements Ti and Ni to improve the wettability,bonding strength and element diffusion effect of the solid/liquid interface at high temperatures.In this paper,the crystal structure and plane structure of the matrix metal Fe and alloying elements Ti,Ni and Fe-Ti,Fe-Ni solid solution in high chromium cast iron were optimized respectively,and the surface energy of different crystal planes were calculated,which provided a theoretical basis for the selection of alloying elements.Using Al2O3 powder,3 Y-ZrO2 powder and alloy elements as raw materials,the ZTA-Ti/Ni composite ceramic substrate was prepared by powder metallurgy technology.The influence of different factors on the wetting effect of high chromium cast iron on each composite ZTA ceramic substrate was studied by high temperature sessile drop method,The main conclusions are as follows:1.The surface energies of the most stable crystal faces of Fe,Ti and Ni crystals increase in order as Ti(0001),Ni(111)and Fe(100).Using low surface energy alloy elements Ti and Ni can form Fe-Ti and Fe-Ni solid solutions with Fe to improve the wettability of cast iron and ceramics.2.The density of each ZTA substrate prepared by the vacuum hot pressing sintering process is above 99%,and alumina and zirconia will form a replacement solid solution at high temperatures.Ti and Al2O3 generate TiO2 and TiAl and a small amount of Ti3Al at high temperature,and the hardness of the substrate has increased;Ni and the components in the ZTA matrix have not chemically reacted,and the hardness of the substrate has decreased.3.There is no wetting between pure ZTA and high chromium cast iron,but the wetting effect is improved obviously by the addition of alloying elements,and the contribution of Ti to the wetting property is greater than that of Ni.When the contents of Ti and Ni are 15 wt.%ZTA and 10 wt.%ZTA,respectively,the wetting effect of ZTA ceramic/high chromium cast iron is the best.At the same time,the diffusion depth of molten iron on the ceramic surface has a significant linear relationship with the contact angle,the smaller the contact angle,the greater the diffusion depth.After the shear experiment,three concentric ring-shaped corrosion pits were left on the surface of the ceramic substrate.The central annular region III was the Fe-Al-Ti/Ni three-phase co-occurrence zone,where the diffusion depth of high chromium cast iron is the thickest.Shear fracture also occurs here.4.In the wetting system,the contact angle decreases with the increase of the substrate surface roughness;With the increase of holding time,the contact angle first decreased significantly and then remained constant,and the influence of holding time on the contact angle was greater than that of the substrate surface roughness.In the non-wetting system,the contact angle increases with the increase of substrate surface roughness,while the holding time has little effect on the contact angle.5.The interface hardness of ZTA-Ti/high chromium cast iron increases with the increase of Ti content,and the shear strength increases first and then decreases.The interface hardness and shear strength of ZTA-Ni/high chromium cast iron increase with the increase of Ni content.