Effect of NiCrBSiFe bionic unit on high temperature erosion wear performance of 304 stainless steel by means of laser cladding

In this work, we show that the surface of 304 stainless steel coupled with laser-cladded bionic units of NiCrBSiFe alloy, based on bioinspired design, exhibits excellent erosion wear resistance under elevated temperature condition. Moreover, the influence of erosion temperature and oxidation on surface were investigated in-depth, indicating that these factors played pivotal roles in the HTE (high temperature erosion) wear performance of 304 stainless steel. The result indicates that, owing to the good properties of NiCrBSiFe bionic units, the erosion wear loss of bionic specimens was significantly lower than that of the as-received specimens in all cases from room temperature to 800 °C. The surface oxidation of specimens shows a strong temperature dependence, governing directly the HTE wear behavior of both bionic unit and substrate. A dense oxide layer acts as a protective barrier against HTE wear, but spalls and then undermines its protective effect, at elevated temperature. Accordingly, at 800 °C, substrate surface undergoes simultaneously fatigue wear and plowing wear, whereas bionic unit surface is dominated only by plowing wear, indicating the obvious improvement in wear resistance in this case. This enhanced performance arises from the synergistic effect of mechanical interlocking and alternating soft-hard structure. This work presents a tailorable, bioinspired strategy for enhancing wear resistance, not only in 304 stainless steel, but also in other materials, thus establishing a theoretical and experimental basis for the design of flexible surface structures under extreme tribological conditions.