Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, t...Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al203 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2O3 coatings. The effects of laser remelting and incorporation of A12O3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed.展开更多
In this work, a novel duplex Ni-P/Ni-Mo-P coating upon the aluminum（Al） substrate was synthesized via an electroless plating, i.e., the binary Ni-P coating as a transition layer and the ternary Ni-Mo-P coating on th...In this work, a novel duplex Ni-P/Ni-Mo-P coating upon the aluminum（Al） substrate was synthesized via an electroless plating, i.e., the binary Ni-P coating as a transition layer and the ternary Ni-Mo-P coating on the top. It was found that the duplex coating was of a high hardness,large elastic modulus,low porosity and excellent corrosion resistance. In addition, experimental results revealed that for a total 20 μm coating thickness, the duplex coating with a 7 μm of the Ni-Mo-P coating exhibited the best corrosion resistance in 0.5 mol/L sulfuric acid solution, which was attributed to its compact structure and low porosity. This duplex Ni-P/Ni-Mo-P coating with a thin ternary Ni-Mo-P layer is expected to solve the problem of low deposition rate of ternary alloy coating and thereby may expand applications of Al and its alloys in the fields of machine manufacture and corrosion environment.展开更多
文摘Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al203 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2O3 coatings. The effects of laser remelting and incorporation of A12O3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed.
基金supported financially by the National Natural Science Foundation of China (No.11174227)the National R&D Infrastructure and Facility Development Program of China (No.2005DKA10400)+1 种基金the Scientific Research Project of Liaoning Province Department of Education (No.L2010396)the Chinese Universities Scientific Fund
文摘In this work, a novel duplex Ni-P/Ni-Mo-P coating upon the aluminum（Al） substrate was synthesized via an electroless plating, i.e., the binary Ni-P coating as a transition layer and the ternary Ni-Mo-P coating on the top. It was found that the duplex coating was of a high hardness,large elastic modulus,low porosity and excellent corrosion resistance. In addition, experimental results revealed that for a total 20 μm coating thickness, the duplex coating with a 7 μm of the Ni-Mo-P coating exhibited the best corrosion resistance in 0.5 mol/L sulfuric acid solution, which was attributed to its compact structure and low porosity. This duplex Ni-P/Ni-Mo-P coating with a thin ternary Ni-Mo-P layer is expected to solve the problem of low deposition rate of ternary alloy coating and thereby may expand applications of Al and its alloys in the fields of machine manufacture and corrosion environment.
