| The development of nuclear power has brought the hope at the world energy crisis. In the rapid development process of nuclear power, the security of nuclear power attracts people’s attention. About the safety of nuclear power, the stability reliability of nuclear materials in the running is one of the most main factors. Stainless steel is widely used in nuclear power equipment, usabilities such as wear resistance, corrosion resistance of the stainless steel play a pivotal role in the nuclear equipment running.Ni-Cr-B-Si as a nickel base alloy is widely used in surface treatment based on the ideal performance, but it still has its shortness in some certain harsh environments. Nb is often added in the alloy powder because of the good reinforcement effect in the alloy. Laser cladding technology have been widely applied to the surface treatment due to its advantages such as low dilution rate, high work efficiency, ability of forming a compact welding layer with no defects and so on.In this paper, we clad nickel base alloy powder added different content of niobium powder on the surface of304austenitic stainless steel by laser cladding technology, then we analysis the influence of cladding parameters, the content of niobium powder added in the nickel base alloy powder on microstructure, microhardness, wear resistance and corrosion resistance of the cladding layer by employing optical microscope (OM), scanning electron microscope (SEM) with energy spectrum (EDX), X-ray diffraction (XRD), Vickers microhardness tester, wear spectrometer, electrochemical potentiodynamic CS350scanner. The main experimental results are as follows:(1) Cladding Ni40+5%Nb and Ni40+20%Nb alloy powder on304austenitic stainless steel surface by semiconductor laser, we confirm range of the optimal parameters for the mixture powder of Ni40and Nb:the laser power is around1000W, scanning speed is about5-8mm/s, feeding rate for5-8g/min, overlapping rate of50%-70%.(2) Ni40cladding layer is mainly composed of y-Ni and Chromium compounds, then a uniform distribution of particles of NbC generated after adding niobium powder in Ni40. With the content of adding niobium increasing, the cladding layer structure refine, phases existed also are changed. When the content of adding niobium power is15%, FeNi3phase disappears and Fe3Ni2phase come out, and we also find NbNi9phase in the cladding layer. In the Ni40alloy powder cladding layer, with the content of adding niobium powder increasing, hardness and wear resistance have the trend of firstly increasing and then decreasing. Hardness reaches maximum when add10%niobium powder, and wear resistance ability is best when add15%niobium in Ni40. For corrosion resistant performance of each cladding layer, the corrosion resistant performance of the cladding layer surface gradually raises when the content of niobium powder added in Ni40increase.(3) The different of laser power used in the experiment has influence on the size of the cladding layer structure and element distribution, without influence on the phase existed. When Cladding Ni40and Ni40+10%Nb alloy powder, with the laser power increasing, the cladding layer hardness decreases and thickness increases. On the friction and wear process, the wear mass lose of Ni40cladding layer declines when laser power increases, while the mass lose of Ni40+10%Nb cladding layer is lower when the power is smaller, and mass lose raises when power increases instead. The corrosion resistance performance of Ni40cladding layer raises with the increase of laser power in the boric acid solution; and for Ni40+10%Nb cladding layer, the corrosion resistance is not linear variability with the increase of power, but they’re similar when the power is1000W and1250W and the laser layer has better corrosion resistance at750W. |
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