Abstract:Single pass 316L alloy powder cladding with different thickness has been carried on the surface of 27SiMn hydraulic support column by using YLS-6000 type ytterbium doped fiber laser. The effect of cladding layer thickness on the coating structure， mechanical properties and corrosion resistance was studied by optical microscope （OM），scanning electron microscope（SEM），energy spectrum（EDS） microhardness meter and electrochemical analysis methods.The results show that，with the increase of cladding layer thickness，the cladding layer structure changes from a single columnar crystal to a layer structure including planar crystal，columnar crystal and dendritic crystal，the surface microhardness of the cladding layer decreases，the corrosion potential and polarization resistance rate increase and the corrosion current density decreases；Compared with 0.3 mm and 0.5 mm thick cladding specimens，both the corrosion potential and polarization resistance rate of 1.0 mm thick cladding layer samples show the largest values of 0.053 V and 22.881Ω·cm2，respectively，while the smallest corrosion current density of 1.018 mA·cm-2 occurs. It is concluded that 1.0 mm thick cladding layer exhibits the best corrosion resistance.

Abstract:利用X射线衍射方法研究了不同Na2H2PO2的质量浓度以及热处理温度条件下化学镀三元Ni-Fe-P和四元Ni-P-B镀层的结构，在温度为200-700℃范围内加热镀层产生结构变化，当热处理温度等于或低于400℃时，镀层的显微硬度随温度增加，这与从Ni-P-B镀层非晶基底中析出（Fe,Ni)固溶体，Ni3P相以及从Ni-P-B镀层（Fe,Ni）固溶体基底中析出Fe2B等相有关，热处理温度大于或等于500℃时，NiP,Fe3P,Fe2B等相析出，同时随温度增加颗粒逐渐粗化，引起镀层软化，在Ni-Fe-P镀层中加入KBH4，经300℃热处理引起镀层显微硬度增加，低于300℃热处理对镀层硬度影响不明显，该现象可由B与Ni-Fe固溶体基底形成了晶化相加以证实。