钨粉表面化学镀镍工艺研究

通过对W粉粒径、络合剂组成、W粉装载量等对W粉表面化学镀Ni的镀层形貌、Ni的利用率和镀速的影响研究，得到了Ni含量可控的W粉表面化学镀Ni的优化工艺参数。然后将制得的Ni包覆W粉与一定比例的Cu粉混合，通过放电等离子烧结（SPS）方法制备了67W-25Cu-8Ni合金，并利用扫描电镜（SEM）、X射线能谱仪（EDS）和X射线衍射仪（XRD）对67W-25Cu-8Ni合金进行了分析。研究结果表明：当W粉粒径为4~6 μm，络合剂为焦磷酸钠60 g/L、三乙醇胺100 g/L和柠檬酸三钠8 g/L时，可以得到包覆紧密、完整均匀的化学镀Ni层，并且可以通过改变装载量控制W-Ni复合粉末中Ni的质量百分比；以化学镀W/Ni复合粉末为原料，通过SPS烧结制备的67W-25Cu-8Ni合金中，W/Ni/Cu界面形成了冶金结合，与W-Cu合金相比，烧结致密度大大提高，达到了97%.

Preparation of Ni-coated W Powder by Electroless Plating

The effects of W powder particle size, complexing agent, W powder loading on the electroless Ni plating on the surface of W powder are analyzed, and the morphology of coated particle, utilization rate of Ni and deposition rate are investigated. The controllable electroless Ni plating process parameters are optimized. The Ni-coated W powders are mixed with Cu powders, and then the mixed powders are sintered to prepare 67W-25Cu-8Ni alloy by using spark plasma sintering (SPS) technique. 67W-25Cu-8Ni alloy is analyzed by scanning electric microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). Results show that, when W powder particle size is in range from 4 μm to 6 μm, the complexing agent of sodium pyrophosphate is 60 g/L, triethanolamine is 100 g/L, and trisodium citrate is 8 g/L. The Ni layer is uniform and complete, and the weight percent of Ni in W-Ni powder can be controlled by adjusting the W powder loading. Metallurgical bonding is achieved at the W/Ni/Cu interface. Compared with W-Cu alloy, the sintering density of 67W-25Cu-8Ni alloy prepared by SPS is greatly increased, reaching to 97%.