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本文用Rietveld分析法测量了以多峰的WC-12Co为原始粉末材料,经三种HVOF(高速氧燃气喷涂)喷枪所制得的24种涂层的相成分。试验中同时考察了不同因素之间的关联性:一方面是热喷涂参数(颗粒温度与速度)与沉积涂层的机械性能(显微硬度与抗摩擦磨损能力)之间的关系;另一方面是涂层的相结构与其性能的关系。结果显示,喷涂温度对涂层性能具有本质内在的影响,而不管采用何种HVOF喷涂工艺方法,产生的低碳化合物主要是W_2C、W和非晶态/纳米晶相。尤其发现只要没有大量W存在的涂层中,WC的脱碳分解产生的非晶/纳米晶相和钨相的存在对增强涂层的机械性能是有利的。涂层中的相与非晶/纳米晶相之间存在线性关系,而与试验中采用的是何种HVOF喷涂工艺无关。试验还发现,仅仅在采用DJ喷枪的HVOF喷涂工艺时,金属W相才存在于纳米晶结构中。
In this paper, the phase composition of 24 coatings prepared from three HVOF (High Speed Oxygen Gas) spray guns with multi-peak WC-12Co as raw powder material was measured by Rietveld analysis. At the same time, the relationship between different factors was examined: on the one hand, the relationship between the thermal spray parameters (particle temperature and velocity) and the mechanical properties of the deposited coating (microhardness and frictional wear resistance); on the other hand Is the coating phase structure and its relationship to the performance. The results show that the spray temperature has an intrinsically significant effect on the properties of the coating, regardless of the HVOF spray process used, resulting in mainly low-carbon compounds W2C, W and amorphous / nanocrystalline phases. In particular, it was found that the presence of the amorphous / nanocrystalline phase and the tungsten phase resulting from the decarburization decomposition of WC is beneficial to enhance the mechanical properties of the coating as long as there is no coating present in substantial amounts. There is a linear relationship between the phases in the coating and the amorphous / nanocrystalline phases, regardless of the HVOF spray process used in the test. It was also found that the W phase only existed in the nanocrystalline structure only during the HVOF spraying process with DJ gun.