热喷涂用镍包裹超细碳化钨复合粉体的制备
Preparation of Ni-coated Superfine WC Composite Material
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摘要: 以Ni(NO3)2·6H2O和NH4HCO3为原料,采用非均相沉淀法在亚微米WC粒子上包裹一层镍的先驱体,再经高温分解和还原,在不同条件下制备了镍包裹WC复合粉体,并用SEM、TEM和XRD等对包裹粉的形貌和组成进行了分析.研究了沉淀剂的加入方式以及反应液浓度对包裹粉的影响.结果表明:当NH4HCO3以慢速加入,反应液浓度为0.14 mol/L时,可制备出粒径为1~2 μm的包裹粉,且粒径分布均匀,分散性好,适合喷涂要求.Abstract: A heterogeneous precipitation method was employed to prepare Ni-coated-WC powders using WC,Ni(NO3)2·6H2O and NH4HCO3 as the raw materials.The coated powders were characterized by SEM,TEM and XRD.An amorphous NiCO3·2Ni(OH)2·2H2O film was uniformly coated on the WC particle surface.After calcined at 550 ℃ for 2 h and reduced at 700 ℃ for 2 h in hydrogen atmosphere,NiCO3·2Ni(OH)2·2H2O was converted to Ni.The particle size of Ni-coated WC powders was about 1-2 μm and had good dispersibility.It is suitable for flame spraying process.
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