37MARCH 2018·SURFACE FINISHING JOURNAL

Electrochemical Process 電化過程

金屬鍍層的電化學沉積法具有眾多優勢。首先，

成本較低。其次，可以通過調整電鍍工藝參數來控制

鍍層的膜厚。再者，與物理沉積方式相比，電鍍工藝也

可以提高沉積速率。然而，一些複雜幾何結構的產品電

鍍時會影響電鍍層分布的效果。當電鍍尺寸較大的產

品時，通過測試產品表面鍍層的膜厚情況，往往會發

現電流密度、鍍層厚度分布不均勻及合金鍍層中鎳金

屬含量差異較大等嚴重問題 (圖1）。

電鍍鎘輔助工具在電鍍鋅鎳 合金工藝中的再應用 Reusability of Cd Electroplating Tooling for Zn-Ni Deposition

Cadmium coatings offer a combination of unique properties that are highly desirable in many engineering applications. Nevertheless, cadmium processing itself possesses serious health and environmental drawbacks because of which new alternatives are sought. Among them, the electroplated Zn-Ni deposits are seen as a viable replacement for Cd coatings.

Electrochemical deposition of metal coatings has many advantages, e.g. low cost, the thickness of the coating can be controlled by adjusting the electrochemical parameters and higher deposition rates in comparison to physical deposition

鍍鉻層綜合應用性能較為突出，因而在眾多工程

領域具有良好應用。然而，電鍍鉻工藝本身會對人體

健康及環境造成較大危害。因此，需要尋求新的

替代工藝。經驗證，在眾多電鍍工藝中，電鍍鋅鎳

合金鍍層是最適合替代電鍍鎘的。

— 1 Bart Van Den Bossche, 2 Agnieszka Franczak, 3 Robrecht Belis* Elsyca NV, Belgium 比利時

* robrecht.belis@elsyca.com

圖 1：飛機起落架部件的 3D 幾何形狀比較電鍍時間對膜厚分布的影響Figure 1: Influence of the process time on the metal layer thickness distribution over complex 3D geometry of a landing gear part

390 sec 秒

電鍍鎘 Cd plating 電鍍鋅鎳合金 Zn-Ni plating

470 sec 秒d[µm] d[µm]

>30

23

21

19

17

15

13

11

9

7

<5

>18

14

13

12

11

10

9

8

7

6

<4

1,800 sec 秒 2,160 sec 秒

1 2 3

38 《国际表面处理》二O一八年三月刊

電化過程 Electrochemical Process

要解決這些問題不能單純地只靠改變電鍍參數

（例如電鍍時間）：電鍍層過厚（紅色區域）和電鍍層

較薄（藍色區域），即使是不同尺寸大小的產品，問題

同樣存在。

從圖2的柱狀圖中我們可以看到產品需要電鍍面

區域、不同膜厚分布占的百分比，以及鋅鎳合金鍍層中

鎳金屬的含量（紅色—超出標準區域，綠色—在標

準範圍之內）。

電鍍鎘或者電鍍鋅鎳合金工藝中產生的電鍍層過

厚或過薄的比例其實是可以通過使用相同結構的輔助

工具來優化並控制的。也就是說，之前用於電鍍鎘的電

鍍輔助工具也可以在電鍍鋅鎳合金工藝中使用。

這個項目是要設計一些合適的輔助工具，它在飛

機起落架部件電鍍鎘和電鍍鋅鎳合金工藝過程中均

可使用。這些電鍍輔助工具的設計與優化是通過電腦

仿真技術來達到的。在這種電腦輔助設計的優化下，

我們有幾重目標：滿足膜厚要求（鎘：最少=10µm，

最大=25 µ m），儘可能地優化總的電鍍時間，儘可

能地讓電鍍輔助工具更加簡單、實用。這都可以通

methods can be obtained. Nevertheless, a common obstacle in an efficient electroplating process is a complex geometry of the parts to-be-plated. For cadmium and Zn-Ni coatings deposited onto large parts with important 3D topology on the surfaces subjected to plating, severe problems with the non-uniformity of current density, layer thickness distribution and deposit composition can be expected (Figure 1).

This cannot be s imply solved by changing the electrodeposition parameters (e.g. plating time): the overplated (red) and underplated (blue) areas, even if in different dimensions, will still exist within the part. The bar graphs presented in Figure 2, indicate the percentage of the active surface area of the part that is contained in different layer thickness intervals, or Ni content intervals in case of Zn-Ni plating (red – out of specs, green – within the specs).

The percentage of overplated and underplated surfaces areas as resulting from both the Cd and Zn-Ni plating processes can be limited with a use of an identical tooling structure. This implies that existing tooling that was developed for the Cd plating process might be re-used for a replacement Zn-Ni plating process.

The project deals with the design of a conformal tooling structure that can be used for both Cd and Zn-Ni electroplating processes of a landing gear part. The conforming components are designed and optimized via computer simulation technology. This computer aided engineering approach of the conformal tooling structure has multiple targets: meeting layer thickness specifications (Cd: min = 10 µm, max = 25 µm), restrict the total plating time as much as possible and keep the tooling configuration as simple and robust as possible. The conforming tooling components were designed and optimised based on layer thickness computer simulations, using in-house developed Elsyca PlatingManager software technology. The tooling concept relies on two types of active tooling components: insulating shields for reducing the overplated areas of the part, and conforming pin anodes (in addition to the main anodes) which address the underplated zones (Figure 3).

Th e i d e n t i c a l to o l i n g s ys te m c a n b e u s e d fo r electroplating of the alternative Zn-Ni coatings (Zn-Ni specs:

圖 2：需要電鍍面區域膜厚及鎳金屬含量的百分比Figure 2: Percentage of the active surface area of the plated LG part, depending on the deposit thickness intervals

電鍍區域面積鎘層膜厚的分布圖Percentage of the active surface area in function

of subsequent Cd layer thickness intervals

鎳含量 Ni content (w/w)

表面

活性

面積

的百

分比

% o

f th

e su

rfac

e ac

tive

are

a

表面

活性

面積

的百

分比

% o

f th

e su

rfac

e ac

tive

are

a

表面

活性

面積

的百

分比

% o

f th

e su

rfac

e ac

tive

are

a

電鍍區域面積鋅鎳合金層膜厚的分布圖Percentage of the active surface area in function

of subsequent Zn-Ni layer thickness intervals

電鍍區域面積鋅鎳合金鍍層鎳含量分布圖Percentage of the active surface area in function

of subsequent Ni content intervals

鍍層厚度 Layer thickness 鍍層厚度 Layer thickness

15

12

9

6

3

015

µm10

<5 µm

10 µm

12.5

12.5 µm15

15 µm

17.5

17.5 µm20

20 µm

22.5

22.5 µm25

25 µm

27.5

27.5 µm30

>30 µm

42

35

28

21

14

7

06

µm7

7 µm

8

8 µm

9

9 µm10

10 µm11

11 µm12

12 µm13

13 µm14

14 µm15

15 µm16

16 µm17

17 µm18

<4 µm

>18 µm

42

35

28

21

14

7

0<0.115

µm0.115

µm0.120

0.120µm

0.125

0.125µm

0.130

0.130µm

0.135

0.135µm

0.140

0.140µm

0.145

0.145µm

0.150

0.150µm

0.155

>0.1555µm

39MARCH 2018·SURFACE FINISHING JOURNAL

Electrochemical Process 電化過程

min = 7 µm, max = 15 µm). In this case, the content of Ni needs to be controlled since the electrodeposition of Zn-Ni alloys has an anomalous behaviour. With the suggested tooling structure both the Zn-Ni layer thickness distribution and Ni content (0.12 – 0.15 w/w) are within given specifications. However, if the Ni content would be observed to be out of the specification range then either the process parameters of Zn-Ni electroplating need to be taken into account or the tooling configuration needs to be improved compared to the one used for Cd plating processes. This can easily be done using the Elsyca PlatingManager software.

參考文獻 References[1] Characterization of a Zinc/Nickel plating bath, Paulo

Vieira, Bart Van Den Bossche, Alan Rose, Plating&Surface Finishing, December 2009

[2] Elsyca PlatingManager: http://www.elsycaplatingmanager.com/

[3] www.elsyca.com / info@elsyca.com

圖 3：該項目的輔助工具：電流遮蔽和輔助象形陽極（除了主陽極之外的）Figure 3: Tooling concept developed for this project: combination of insulating shields and conforming anodes (addition to the main anodes)

針狀輔助陽極 Pin anodes 遮蔽 Shields

優化產品在鍍槽的擺放位置Position of the optimized

part in the tank

前面 Front side 後面 Back side

過一種基於電腦模擬膜 厚的技術實現，即Elysca

PlatingManager 電鍍仿真軟件。

這些輔助工具主要是依賴兩組活性部件：一，用

於縮小產品膜厚過厚區域的絕緣屏蔽體，二，根據產品

的實際情況而設計的輔助象形陽極（除了主要陽極之

外的）（圖3）。

同樣的電鍍輔助工具也可用在電鍍鋅鎳合金工藝

中（鋅鎳合金膜厚標準：最少=7µm, 最大=15µm）。在

這種情況下，合金中鎳金屬的含量需要嚴格控制，因為

電鍍鋅鎳合金是一種異常共沉積現象。在電鍍輔助工具

的幫助下，鋅鎳合金鍍層的膜厚和鎳含量（12~15%）

都會控制在給定範圍之內。但是，如果鎳金屬含量超

出規定範圍，這時我們既要考慮電鍍鋅鎳合金的工藝

參數的變化，也要考慮輔助工具相對與之前電鍍鎘時

的一些區別，並加以優化。以上這些通過使用Elsyca

PlatingManager電鍍仿真軟件可以快速實現。