The Influence Of CeO₂ Of Wc Enhance Ni Base Laser Cladding Layer Organization And Performance

In recent years, People has been paying widely attention on the N i radical- WC composite coating covered on the metal substrate surface, due to the coating can significantly improve the material’s hardness and abrasive resistance. Scholars domestic and overseas have obtained abundant achievement on taking varieties of methods to make the coa ting on different substrate. However, there is a little repo rt and discuss on how the volume of the CeO2 influe nce the coa ting’s structure and perfor mance. Thus, it is necessary to have a deep discuss on how the volume of the CeO2 influence the N i radical- WC composite coating’s structure and performance. The aging treatment of the cladding layer based on the perfect CeO2 addition volume. Also, the time of aging treatment influe nce on the cladd ing layer ’s structure and performance need to be discussed. Thus, the thesis can provide reference to prepare high performance N i radical- WC composite coating.The experiment adopted the HGL- 6000 crosscurrent and CO2 laser to making Ni radical- WC composite coating on the 316 L stainless steel surface. Also, the experiment adopted metallographic microscope(OM), scanning electron microscope(SEM) and its attached spectrometer(EDS), XRD diffraction to analyze the cladd ing layer’s surface morphology, organization, composition and phase component. The expe riment investigated different volume of CeO2 and different time of aging treatment time ’s influence on organization performance of N i radical- WC cladding layer organization performance. The experiment adopted HVS- 10 Digital Display Vickers Hardness Tester and HR – 150 A Rockwell Hardness Tester to testing the microhardness and surface hardness under various CeO2 volume and a ging treatment.The experimental results showing that according to the microtopo graphy of the cladd ing specimens section,the cladding layer can be divided into three regions: Cladding layer, combining zone and heat affected zone. When the volume of the CeO2 within the scope of the 0-1.0%, with the increasing of CeO2, the organization of the cladd ing layer gradually became tight; the melt volume of WC increased gradually; the cladding layer section and surface hardness decreased; When the volume of the CeO2 is 1.5%, the organization is bulkier than 1.0%; the melt volume of WC decreased; cladding layer section and surface hardness decreased; the enrichment of Fe and N i appeared at cladding layer transgranular. And the segregation of element Cr and W produced at crystal boundary. C ladding layer mainly contained the phase of(Ni,Fe)、Cr4Ni15W、Cr23C6、Ni17W3、W2C. When the treatment temperature is 860 ℃ and the volume CeO2 is 1.0%, the experiment did different aging treatment to the cladding layer. When the processing time was between 4 hours and 8 hours, the cladd ing layer transition region turned black and grain size increased gradually with the processing time increased and the cladding layer section and surface hardness reduced gradually. When the processing time was 16 hours, cladding layer grain was smaller; the transition region became less black; cladding layer section and surface hardness improved, but it was still lower than untreated and the phase mainly the same to untreated.