表面技术
錶麵技術
표면기술
Surface Technology
2015年
11期
46-51
,共6页
徐小江%赵晴%王春霞%于宽深%邱媛
徐小江%趙晴%王春霞%于寬深%邱媛
서소강%조청%왕춘하%우관심%구원
无氰镀银%高温防变色%脉冲镀银%孔隙率%后处理
無氰鍍銀%高溫防變色%脈遲鍍銀%孔隙率%後處理
무청도은%고온방변색%맥충도은%공극솔%후처리
cyanide-free silver plating%discoloration resistance at high temperature%pulse silver plating%porosity%post-pro-cessing
目的 探寻无氰镀银层高温变色的原因,以增强无氰镀银层的防高温变色性能. 方法 采用硫代硫酸盐体系在紫铜片上镀银,并进行无惰性气体保护的300 ℃×1 h烘烤. 借助扫描电镜( SEM)观察镀层高温烘烤后的微观形貌,采用能谱仪( EDS)检测镀层中各元素的含量与分布,探讨银层厚度、供电方式、后处理工艺对镀层防高温变色性能的影响. 结果 当直流电镀层厚度达到9 μm,脉冲电镀层厚度达到6 μm时,镀层经高温烘烤后不变色. 而经水溶性银保护剂、重铬酸钾、PMTA处理后的镀层(厚6 μm)均在高温烘烤后发生了变色情况. 扫描电镜观察显示,高温变色镀层表面有凸起状裂纹,能谱仪检测到有铜原子外渗现象. 结论 高温下铜原子的外渗导致了镀层变色. 采用脉冲方式进行电镀,可以使镀银层孔隙率降低. 通过增加镀银层厚度和采用脉冲电镀,能够提高镀银层的防高温变色性能.
目的 探尋無氰鍍銀層高溫變色的原因,以增彊無氰鍍銀層的防高溫變色性能. 方法 採用硫代硫痠鹽體繫在紫銅片上鍍銀,併進行無惰性氣體保護的300 ℃×1 h烘烤. 藉助掃描電鏡( SEM)觀察鍍層高溫烘烤後的微觀形貌,採用能譜儀( EDS)檢測鍍層中各元素的含量與分佈,探討銀層厚度、供電方式、後處理工藝對鍍層防高溫變色性能的影響. 結果 噹直流電鍍層厚度達到9 μm,脈遲電鍍層厚度達到6 μm時,鍍層經高溫烘烤後不變色. 而經水溶性銀保護劑、重鉻痠鉀、PMTA處理後的鍍層(厚6 μm)均在高溫烘烤後髮生瞭變色情況. 掃描電鏡觀察顯示,高溫變色鍍層錶麵有凸起狀裂紋,能譜儀檢測到有銅原子外滲現象. 結論 高溫下銅原子的外滲導緻瞭鍍層變色. 採用脈遲方式進行電鍍,可以使鍍銀層孔隙率降低. 通過增加鍍銀層厚度和採用脈遲電鍍,能夠提高鍍銀層的防高溫變色性能.
목적 탐심무청도은층고온변색적원인,이증강무청도은층적방고온변색성능. 방법 채용류대류산염체계재자동편상도은,병진행무타성기체보호적300 ℃×1 h홍고. 차조소묘전경( SEM)관찰도층고온홍고후적미관형모,채용능보의( EDS)검측도층중각원소적함량여분포,탐토은층후도、공전방식、후처리공예대도층방고온변색성능적영향. 결과 당직류전도층후도체도9 μm,맥충전도층후도체도6 μm시,도층경고온홍고후불변색. 이경수용성은보호제、중락산갑、PMTA처리후적도층(후6 μm)균재고온홍고후발생료변색정황. 소묘전경관찰현시,고온변색도층표면유철기상렬문,능보의검측도유동원자외삼현상. 결론 고온하동원자적외삼도치료도층변색. 채용맥충방식진행전도,가이사도은층공극솔강저. 통과증가도은층후도화채용맥충전도,능구제고도은층적방고온변색성능.
Objective To search for the cause for the high-temperature color change of cyanide-free silver coating, in order to enhance the discoloration resistance of the cyanide-free silver coating at high temperature. Methods Thiosulfate system was used to plate silver on the copper sheet, followed by baking at 300℃ ( without inert gas protection) for 1 h. Scanning electron microscopy ( SEM) was used to observe the microstructure of the coating after high-temperature baking, and energy spectrometer ( EDS) was used to detect the content and distribution of elements in the coating. The effects of silver layer thickness, power supply mode, and the post-processing technology on the discoloration resistance of the coating at high temperature were discussed. Results When the thickness of direct current ( dc) plating layer was 9 μm and the thickness of pulse electroplating layer was 6 μm, the coating did not change color after high-temperature baking. But the coatings ( with a thickness of 6 μm) after treatment with water soluble sil-ver protectant, potassium dichromate, and PMTA all changed color after high-temperature baking. Scanning electron microscopy showed convex-shape cracks on the surface of the high-temperature discolored coating, and spectrometer detected copper atoms leakage phenomenon. Conclusion Leakage of copper atoms at high temperature led to discoloration of the coating. Pulse plating could decrease the porosity of the coating. Increasing the silver coating thickness and using the pulse plating could improve the high-temperature discoloration resistance of silver coating.
