Phase and element distribution of high chromium cast iron ztap / HCCI composite

Figure 1 shows the XRD pattern of ztap / HCCI composite. The phases of the composites mainly include Al2O3 in ceramic phase, m-ZrO2 in monoclinic phase and t-ZrO2 in tetragonal phase. The main reason is that the amount of retained martensite is not detected. The carbide phase is (Cr, Fe) 7C3 type carbide, and its microhardness is as high as HV 1200 ~ 1800, which is the main source of good wear resistance of HCCI.

The interface between ztap and metal matrix in ztap / HCCI composite was analyzed by EDS scanning. The element distribution in the interface is shown in Fig. 2. It can be seen that Al element almost does not diffuse in ceramic phase, and a small amount of Zr element diffuses. The aggregation region of Cr in the metallic phase is consistent with that of carbide in SEM, and that of Si is consistent with that of Fe, which indicates that Si is mainly dissolved in Fe matrix, and the solubility of Cr is reduced, which makes CR mainly form carbide with C element, and a small amount is dissolved in Fe matrix. 5. Ni is added to the metal matrix as a trace element. The role of V element is to improve the carbide size, promote the carbide spheroidization, eliminate the coarse columnar crystal structure to refine the grain, while Ni can improve the wettability between Fe matrix and Al2O3.