| Metal substrate/glass-ceramic coating composite materials have become a research focus in the field of wear-resistant material because of its manifold excellent performances such as high hardness, wear-resistance and resistcorrosion. However, glass-ceramic is a kind of brittle material, which has low toughness and easy to wear under the erosion conditions. The design concept of functionally gradient materials(FGM) was adopted in this paper, the glassceramic was toughened by adding certain components 3Y-TZP(Zr O2 with 3mol % Y2O3) in it, so as to effectively solved the shortcomings of his big brittleness. The preparation method, properties and organizational structure of3Y-TZP/LZAS glass-ceramic gradient coatings were studied, the multiple sintering characteristic and erosion wear mechanism of 3Y-TZP/Li2O-Zn O-Al2O3-Si O2(LZAS) glass-ceramic gradient coatings were focused studied.3Y-TZP/LZAS glass-ceramic gradient coatings on Q235 steel substrate were prepared by using enameling and sintering method in this paper, and the preparation method, properties and organizational structure of 3Y-TZP/LZAS glass-ceramic gradient coatings were studied. The results indicated that the interfaces combined closely, there were no crack defects. The microhardness and fracture toughness of gradient coatings increased with the increase of 3Y-TZP content. The bonding strength between gradient coatings and Q235 substrate was highly up to 16.3 MPa. Thermal cycling times was more than 30 when the gradient coatings underwent thermal cycling test at 300 ℃. The gradient coatings had preferable thermal shock resistance.The effects of multiple sintering on structure and properties of3Y-TZP/LZAS glass-ceramic gradient coatings on Q235 steel substrate were investigated. The results indicated that the precipitation of coating material in the grain and grew up can be promoted by multiple sintering, no new crystalline phase was found in the coating material. Multiple sintering leaded to the rise of material porosity, the decrease of relative density and the decrease of material properties. On the permise of meeting the requirement, less layers of the gradient coatings should be made.At 15°, 30°, 45°, 60°, 75°and 90°angles of erosion, and the time of erosion was controlled, then erosion test was made on different layers of gradient coatings by using self-made erosion wear tester, compared with Q235 steel, the erosion rates of volume were determined, and the erosion mechanism of gradient coatings at different erosion angles was researched. It is shown from the results that the gradient coatings erosion rates of volume increase firstly then decrease as the erosion angles increase, and the maximum is brought at 60° angle. The erosion wear resistance of gradient coatings increases as the layers increase. The main erosion mechanism at low erosion angle is cutting wear caused by cutting and plough cutting effect, and micro-crack fracture caused by pounding and forging effect at high erosion angle, both cutting, plough cutting effect and pounding, forging effect are strong at 60° angle, so that the coating wear loss is the biggest. The gradient coatings have more excellent erosion resistance than Q235 steel at low erosion angles from 15° to 30°, so that the gradient coatings are more suitable for lower erosion angles wear condition from 15° to 30°, and three or four layers gradient coatings effect better. At the low erosion angle of30°, the erosion rates of volume of gradient coatings increase as the increase of erosion wear abrasive diameter, speed, hardness within the scope of the condition of certain erosion. |
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