化学镀制备镍包铜复合粉末的工艺与表征

本文分别选用次亚磷酸钠、联氨做还原剂，通过化学镀制取了镍包铜复合粉末，实验发现：次亚磷酸钠作还原剂时，用盐酸活化、酸化后的铜粉，可直接在其表面进行化学镀，镀覆效果良好，可取代昂贵的氯化钯活化处理；而用联胺作还原剂，可以直接在铜粉表面实现镀覆。采用SEM（包括EDS），XRD对制取的复合粉进行了分析测试，结果表明：复合粉末表面较原始粉末粗糙，包覆层均匀；用次亚磷酸钠作还原剂，所得到的复合粉末包覆层为镍磷合金，而用联胺作还原剂，制取的复合粉末仅由镍铜两相组成，未引入其他元素。对Ni／Cu复合粉的化学成分进行测试，结果表明：Ni／Cu复合粉末符合粉末冶金材料的要求，通过氢还原可以降低含碳量、氢损，提高复合粉的粉末冶金性能指标。

Characterization and processes study of electroless plating nickel on the copper particles

Some nickel coated copper powders were prepared by electroless plating with hypophosphite and hydrazine as reducing agents respectively. The results showed: with hypophosphite reducing agent, the nickle could well plate on copper powders that were activited and acidified by HCl solution instead of expensive PdCl_2, and with hydrazine reducing agent, the copper powders could be directly plated on without any activition agent.The morphology of composite powders were observed by SEM, and the results showed the surface of composite powder is coarse, and the coating is uniform. XRD and EDS analysis showed that the coating of composite powders prepared with hypophosphite is of Ni- P alloy, and the coating of composite powders prepared with hydrazine reduction is of pure nicke. Chemical Composition of Ni/Cu composite powders were measured, the results showed that Ni/Cu composite powders meet the requirement of powder metallurgy, and the carbon content and the hydrogon loss of composite powder are decreased with hydrogon reducing, which could enhance powder metallurgy properity of composite powder.