具备Al2O3原位合成特性的WC复合粉末设计与涂层

Design of WC Composite Powders and Coatings with Characteristic of in-situ Synthesis Al2O3

摘要:

利用球磨法将Al粉添加到亚微米结构WC-12Co粉末中，设计并制备了具有Al2O3原位合成特性的纳米结构WC-Co-Al粉末。XRD分析显示球磨10h、30h和50h后的粉末中WC平均晶粒尺寸为93.1nm、39.0nm和44.8nm。超音速火焰（HVOF）喷涂时，WC-Co-Al粉末比球磨前WC-12Co粉末扁平化更好，涂层孔隙率为0.57%，比WC-12Co涂层（1.62%）更低。粉末中的Al元素与氧气反应原位生成了Al2O3硬质陶瓷颗粒，有效抑制了WC的氧化脱碳。WC-Co-Al涂层显微硬度为1298?3HV0.1，比WC-12Co涂层高出约36%，这得益于Al2O3颗粒的增强效应，WC晶粒纳米化和孔隙率降低。

Abstract:

Nanostructured WC-Co-Al powders with characteristic of in-situ synthesis Al2O3 were synthesized from submicron structured WC-12Co powder and Al powder using ball-milling method. XRD analysis showed that the average size of WC grains was 93.1nm, 39.0nm and 44.8nm after milling 10h, 30h and 50h, respectively. When sprayed by high velocity oxygen fuel (HVOF) thermal spraying, WC-Co-Al powders were more easily flattened than WC-12Co powder without ball-milling. The porosity of WC-Co-Al coating was only 0.57% which was much lower than that of WC-12Co coating with a value of 1.62%. During spraying Al reacted with oxygen, which effectively inhibited the decarburization of WC, and Al2O3 hard ceramic particles were in situ generated in coatings. The microhardness of WC-Co-Al coating was 1298?3HV0.1, higher about 36% than that of WC-12Co coating, which mainly benefitted by the enhancement effect of Al2O3 particles, nanocrystallization of WC phase and lower porosity.