| 摘要: | 本論文以即時影像導引法自焦磷酸鹽鹼性鍍浴中，經連續式電鍍成功製備出直徑50 ~ 70 ?m之銅鋅合金微柱，進而研究其結構及機械性質。改變微電鍍製程之實驗參數如電極間距(15、20、25、30 ?m)、兩極間偏壓(4.3、4.4、4.5、4.6 V)和鍍浴中銅離子濃度(0.04、0.02、0.01、0.005 M)，顯示其對製作合金微柱之結構、組成及機械性質具有影響。
理論上，可經由平板電極、微電極的陰極極化曲線的研究來求得銅、鋅共鍍析出合金的適當電位。所製得之合金微柱，可使用感應耦合電漿質譜儀(ICP-MS) 分析其組成、掃描式電子顯微鏡(SEM)觀察其形貌、X光繞射儀(XRD)解析其晶體結構與合金相，並以奈米壓痕儀與微拉伸試驗儀對其做機械性質的測試。
在微電鍍製程中，固定偏壓在4.4 V，若提升兩極間距(由15到30 ?m)，所得微柱之表面顆粒大小由195減小至80 nm，形貌則由粗糙轉變成平滑；微柱組成中鋅含量由23.51減低到14.34 at.%；機械性質，由奈米壓痕測得其硬度隨兩極間距增加而增大(間距在30 ?m時硬度達3.11 GPa)。當兩極間距固定在25 ?m下，偏壓若由4.3增加到4.6 V，則微柱成分中鋅含量由15.88增加到34.83 at.%，且硬度增加(偏壓在4.6 V下之硬度在3.51 GPa)。當兩極間距與偏壓分別固定在4.4 V 與 25 ?m時，若鍍浴中銅離子濃度由0.005 增加到0.04M時，所得微柱之鋅含量、硬度與彈性模數明顯降低，在銅離子濃度為0.005 M時，所得微柱之含鋅量、硬度與彈性模數分別為43.30 at.%、3.79 GPa與92.14 GPa。
XRD分析得知: 微柱之晶體特徵峰屬於FCC結構的α相，隨組成中含鋅量的增加而逐漸向低角度偏移，當含鋅量達43.30 at.%時，微柱中有六方晶的ε相生成。
Copper-zinc (Cu-Zn) alloying micro pillars with their diameter in 50 ~ 70 ?m were fabricated by continuous micro-electroplating in pyrophosphate bath under real-time monitoring and control. The effect of parameters such as the gap between electrodes (at 15, 20, 25 and 30 ?m), the electrical bias between electrodes (at 4.3, 4.4, 4.5 and 4.6 V) and the copper concentration in the bath (at 0.04、0.02、0.01、0.005 M) on the surface morphology, composition, microstructure and mechanical property was investigated.
The potential used in electrochemical co-deposition of Cu and Zn was theoretically deduced from the cathodic polarization of the planar and column electrodes in Cu- and Zn-containing baths, respectively. Surface morphology of the alloying micro pillars was examined by SEM, their composition and microstructure were determined by ICP-MS and XRD, respectively. The mechanical properties were evaluated by nano indenting test and micro stress tensile test.
When the electrochemical deposition conducted at 4.4 V with increasing the gap between electrodes from 15 to 30 ?m, the micro pillars fabricated revealed a smoother surface morphology (with decreasing their particles from 195 to 80 nm in diameter) and depict their composition decreasing the Zn content from 15.88 to 14.34 at.%, The mechanical property, determined by nano indentation, displayed an increase in hardness up to 3.11 GPa at an electrode gap of 30 ?m. In the case that electrodeposition conducted at an electrode gap of 25 ?m, the micro pillars tended to increase their Zn-content from 15.88 to 34.83 at.% with increasing the electrical voltage from 4.3 to 4.6 V, then the hardness increased up to 3.51 GPa at 4.6 V. In the case for the electrochemical deposition performed at 4.4 V with an electrode gap of 25 ?m, the micro pillars was found to increase Zn-content and hardness in the alloy with decreasing the copper concentration from 0.04 to 0.005 M in the bath. The micro pillar was fabricated to contain 43.30 at.% Zn and reveal the hardness at 3.79 GPa, elastic modulus at 92.14 GPa.
According to XRD analysis, the micro pillars belong to α-phase brass in face-centered cubic (FCC) crystal. The characteristic peaks of this α-phase shifted to low angle with increasing the Zn-content and turned out to form ε-phase belonged to hexagonal structure as the Zn-content increased to a level at 43.30 at.%. |
