Effects of Thermal Treatment on Microstructure and Wear Properties of Ni60/CeO2 Composite Coating 35CrMoV Steel by Laser Cladding

Abstract

Laser cladding Ni60/2.0 wt.%CeO2 self-lubricating anti-wear composite coatings on 35CrMoV steel were thermally treated at 25 °C, 500 °C, 600 °C and 700 °C for 1 h, respectively. The macroscopic morphology of composite coatings was characterized by optical microscopy. The evolution of microstructure was studied by scanning electron microscopy. The precipitated phase of the coating was analyzed by X-ray diffractometer. The microhardness and wear properties of the composite coatings were measured by microhardness tester and friction and wear test. The effects of thermal treatment and no thermal treatment on the mechanical properties of the composite coatings were systematically studied by the above experiments. The experimental analysis shows that the main phase composition of Ni60/2.0 wt.%CeO2 composite coating is γ-(Ni, Fe), Cr7C3, Cr23C6, CrB, CrFeB and Cr2Ni3. Meanwhile, in XRD, it can be seen that the diffraction peak has shifted to the left and the single diffraction peak is decomposed into double diffraction peaks with the thermal treatment at 700 °C, which indicates that the lattice in the coating phase has a certain distortion. Compared with the coatings without thermal treatment, Ni60 cladding layer has more uniform solute distribution and a denser and more uniform structure after thermal treatment at 700 °C. The laser cladding anti-wear composite coating demonstrates that the wear resistance performance shows the greatest improvement after thermal treatment at 700 °C.

Effect of Heat Treatment on Microstructure and Tribological Properties of Laser Cladding CeO2/Ni60 Composite Coating on 35CrMoV Steel

“…Figure 8a clearly shows t the wear quantity of the cladding layer at 25 °C and 700 °C is almost the same, whic 28,646 μm 3 and 27,583 μm 3 , respectively. The wear of the coating at 500 °C is only 16, μm 3 , which is 43% less than that of the coating with no-annealing. The wear loss coatings at 600 °C is 20,354 μm 3 , which is slightly higher than that at 500 °C.…”

“…(4) The wear quantities of Ni60 coatings at 25 • C, 500 • C, 600 • C and 700 • C are 28,646 µm 3 , 16,583 µm 3 , 20,354µm 3 and 27,583 µm 3 , respectively. The wear quantity of the coating at 500 • C is only 16,583 µm 3 , which is 43% less than that of the coating without annealing.…”

“…To work under high stress conditions, 35CrMoV alloy steel is often manufactured as a key component [1,2]. The working life of the parts cannot be guaranteed because the parts are in service under harsh conditions for a long time [3]. The resultant damage of important parts will not only delay the working time, but also make it difficult to guarantee the repair quality even if the damaged parts are repaired by traditional methods [4].…”

Parameter Optimization and Mechanical Properties of Laser Cladding of 316L Stainless Steel Powder on G20Mn5QT Steel

“…This composite coating was found to have a clean wear surface with shallower and more uniform scratches. In the past, many authors [17][18][19][20][21] have repaired different materials using LC technology and studied their wear resistance. It was found that the wear resistance of the coating repaired by LC technology has been improved.…”