TWI670396B - Surface treatment method for aluminum alloy - Google Patents
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Abstract
本發明提供一種鋁合金之表面處理方法，其包含浸鋅步驟、熱擴散步驟及鎳鎢電鍍步驟。浸鋅步驟中，一鋁合金材質之基材置於含氧化鋅及氫氧化鈉之一浸鋅液中，使基材的表面改質形成一浸鋅層，熱擴散步驟中，改質後之基材置於熱處理環境中，以穩定浸鋅層的結構，鎳鎢電鍍步驟中，冷卻熱處理之基材，並置於一鎳鎢電鍍處理液執行電鍍，使浸鋅層遠離基材之一側形成一鎳鎢電鍍層；藉此，本發明的處理流程快速，而且運用鎳鎢電鍍方式具有環保、無汙染的效果，還可提升產品高溫耐磨耗的功效。The invention provides a surface treatment method for an aluminum alloy, which includes a zinc dipping step, a thermal diffusion step, and a nickel tungsten plating step. In the zinc dipping step, an aluminum alloy substrate is placed in a zinc dipping solution containing zinc oxide and sodium hydroxide to modify the surface of the substrate to form a zinc dipping layer. In the thermal diffusion step, the modified The substrate is placed in a heat-treated environment to stabilize the structure of the zinc-impregnated layer. In the nickel-tungsten plating step, the heat-treated substrate is cooled and placed in a nickel-tungsten plating treatment solution to perform plating, so that the zinc-impregnated layer is formed away from one side of the substrate. A nickel-tungsten plating layer; thereby, the processing flow of the present invention is fast, and the use of the nickel-tungsten plating method has the effects of environmental protection and pollution-free, and can also improve the effect of high temperature wear resistance of the product.
Description
本發明係關於一種化學電鍍領域的處理方法，尤指一種在鋁合金表面上執行鎳鎢電鍍的鋁合金之表面處理方法。The invention relates to a treatment method in the field of chemical electroplating, and in particular to a surface treatment method of an aluminum alloy that performs nickel-tungsten plating on the surface of an aluminum alloy.
按，鋁合金具有質量輕且強度高，因此常被選擇用來改善產品輕量化的替代材料，再加上鋁合金的成本相對低於銅、鐵等金屬材質，而且鋁合金還具有回收再利用的效果，藉以近年來鋁合金的使用量有逐年上升的驅勢。According to the fact that aluminum alloy has light weight and high strength, it is often selected as an alternative material to improve product lightweighting. In addition, the cost of aluminum alloy is relatively lower than that of copper, iron and other metal materials, and aluminum alloy also has recycling. As a result, the use of aluminum alloys has been increasing year by year in recent years.
但是，鋁合金具有硬度差、耐磨耗差及耐蝕性差的缺點，如今產業為了改善鋁合金上述的缺點，通常會在鋁合金產品的表面執行電鍍工藝。However, aluminum alloys have the disadvantages of poor hardness, poor wear resistance, and poor corrosion resistance. In order to improve the above-mentioned shortcomings of aluminum alloys, the industry usually performs an electroplating process on the surface of aluminum alloy products.
而目前工業用電鍍工藝，大多以六價鉻(Hexavalent Chromium)鍍液為主，其中，鉻和鉻化合物在鋁合金表面處理上廣泛應用在活塞環、汽車工業的軸承、避震桿和支架，這些常受到大量磨耗的工件表面常以硬鉻處理，雖然可提升鋁合金工件的使用壽命，但，若硬鉻應用在引擎內燃機時，由於引擎燃燒時所產生的高溫達2500℃，而硬鉻的硬度在溫度高於400℃時會開始下降，且抵抗磨耗的能力也會跟著變差，如此還是會產生使用壽命降低的問題。At present, most of the current industrial electroplating processes are mainly hexavalent chromium (Hexavalent Chromium) plating solution. Among them, chromium and chromium compounds are widely used in aluminum alloy surface treatment in piston rings, bearings, suspension rods and brackets in the automotive industry. The surfaces of these workpieces that are subject to a lot of wear are often treated with hard chromium. Although the service life of aluminum alloy workpieces can be improved, if hard chromium is used in an internal combustion engine, the high temperature generated by the combustion of the engine can reach 2500 ° C. When the temperature is higher than 400 ° C, the hardness will start to decline, and the resistance to abrasion will also worsen. This will still cause the problem of reduced service life.
再者，電鍍硬鉻會產生有毒性的廢水，因而會危害周圍生態環境，若要處理毒性的廢水，需要額外增加整體工藝的成本，藉此，針對傳統電鍍硬鉻工藝的缺失及汙染問題，有待相關業者解決之。In addition, electroplated hard chromium will produce toxic wastewater, which will endanger the surrounding ecological environment. To deal with toxic wastewater, the cost of the overall process needs to be increased. In order to address the lack of traditional electroplated hard chromium processes and pollution problems, It remains to be resolved by relevant industry players.
為解決上述課題，本發明提供一種鋁合金之表面處理方法，其處理流程快速，經電鍍處理的鋁合金具有高溫耐受性及化學耐受性的效果，而且製程無毒無汙染，符合環保的規範。In order to solve the above problem, the present invention provides a surface treatment method for aluminum alloy, which has a fast processing process. The electroplated aluminum alloy has the effects of high temperature resistance and chemical resistance, and the process is non-toxic and pollution-free, and meets environmental protection standards. .
為達到上述目的，本發明提供一種鋁合金之表面處理方法，其包含浸鋅步驟、熱擴散步驟及鎳鎢電鍍步驟。於浸鋅步驟中：一鋁合金材質之基材置於含氧化鋅及氫氧化鈉之一浸鋅液中，使基材之表面改質形成一浸鋅層，其中，浸鋅液之氧化鋅與氫氧化鈉間的含量比例為1：15至1：25，且浸鋅液之反應溫度不高於30℃，反應時間小於1分鐘；於熱擴散步驟中：改質後之基材置於熱處理環境中，並加熱介於100℃至400℃間，加熱時間為1小時，使浸鋅層之鋅粒受熱擴散至基材，於鎳鎢電鍍步驟中：冷卻熱處理之基材，並置入於含有檸檬酸鈉、硫酸鎳、鎢酸鈉、氯化銨及溴化鈉之一鎳鎢電鍍處理液執行電鍍，鎳鎢電鍍處理液的pH值介於6.5至8.5間，使浸鋅層遠離基材之一側形成一鎳鎢電鍍層。To achieve the above object, the present invention provides a surface treatment method for aluminum alloy, which includes a zinc dipping step, a thermal diffusion step, and a nickel-tungsten plating step. In the zinc impregnation step: a substrate made of aluminum alloy is placed in a zinc impregnation solution containing zinc oxide and sodium hydroxide, and the surface of the substrate is modified to form a zinc impregnation layer. The content ratio between sodium hydroxide and sodium hydroxide is 1:15 to 1:25, and the reaction temperature of the zinc dipping solution is not higher than 30 ° C and the reaction time is less than 1 minute. In the thermal diffusion step: the modified substrate is placed In the heat treatment environment, and heating between 100 ° C and 400 ° C, the heating time is 1 hour, so that the zinc particles of the zinc-impregnated layer are diffused to the substrate by heating. In the nickel-tungsten plating step, the heat-treated substrate is cooled and placed Electroplating is performed on a nickel-tungsten plating treatment solution containing one of sodium citrate, nickel sulfate, sodium tungstate, ammonium chloride, and sodium bromide. The pH value of the nickel-tungsten plating treatment solution is between 6.5 and 8.5 to keep the zinc impregnation layer away from A nickel-tungsten plating layer is formed on one side of the substrate.
藉此，本發明的處理流程快速，而且運用鎳鎢電鍍方式具有環保、無汙染的效果，還可提升產品高溫耐磨耗以及化學耐受性的功效。Therefore, the processing process of the present invention is fast, and the use of nickel-tungsten plating has the effects of environmental protection and pollution-free, and can also improve the effects of high temperature wear resistance and chemical resistance of the product.
為便於說明本發明於上述發明內容一欄中所表示的中心思想，茲以具體實施例表達。In order to facilitate the description of the central idea of the present invention in the above-mentioned summary of content, specific embodiments are described below.
請配合參閱圖1至圖3所示，本發明提供一種鋁合金之表面處理方法，其依序包含浸鋅步驟S1、熱擴散步驟S2及鎳鎢電鍍步驟S3。Please refer to FIG. 1 to FIG. 3. The present invention provides a surface treatment method for aluminum alloy, which includes a zinc dipping step S1, a thermal diffusion step S2, and a nickel tungsten plating step S3 in this order.
浸鋅步驟S1：將一鋁合金材質之基材10浸置於含氧化鋅及氫氧化鈉之一浸鋅液中，使基材10之表面形成一浸鋅層20，且浸鋅液之反應溫度不高於30℃，反應時間小於1分鐘。Zinc impregnation step S1: immerse a substrate 10 made of an aluminum alloy in a zinc impregnation solution containing one of zinc oxide and sodium hydroxide, so that a surface of the substrate 10 forms a zinc impregnation layer 20, and the reaction of the zinc impregnation solution The temperature is not higher than 30 ° C, and the reaction time is less than 1 minute.
特別說明的是，浸鋅液中的氧化鋅及氫氧化鈉主要作為主劑，本發明為了探討氧化鋅與氫氧化鈉間的配比參數是否會影響浸鋅效率，因此，本實施例將氧化鋅與氫氧化鈉間的含量比例分別調配成1：5、1：10、1：15、1：20及1：25。 表1浸鋅液中的氧化鋅與氫氧化鈉配比參數及影響
經銳意實驗發現，當氧化鋅與氫氧化鈉為1：5時，氧化鋅溶解速度很慢，而在靜置24小時後，浸鋅液中會產生沉澱物；當氧化鋅與氫氧化鈉為1：10時，氧化鋅的溶解速度還是呈現緩速情況，而在靜置72小時之後，浸鋅液中會產生微量的棉絮狀沉澱物，後續靜置到96小時之後，浸鋅液則會明顯產生沉澱物；進一步說明，當氧化鋅與氫氧化鈉的含量比值為1：15、1：20、1：25時，靜置超過168小時後，浸鋅液均未有出現任何沉澱物，而本實施例考量浸鋅反應時，基材10溶解出的氧化物鈍態薄膜反應也會消耗浸鋅液中的氫氧離子，反而會降低浸鋅液的穩定性以及提升後續處理成本，因此，選用氧化鋅與氫氧化鈉含量比例為1：20作為本發明之最佳值，其中，10g/L的氧化鋅及200g/L的氫氧化鈉係作為本實施例之實驗參數，但不限於此。Through intensive experiments, it was found that when zinc oxide and sodium hydroxide are 1: 5, the dissolution rate of zinc oxide is very slow, and after standing for 24 hours, a precipitate will be produced in the zinc immersion solution; when zinc oxide and sodium hydroxide are At 1:10, the dissolution rate of zinc oxide is still slow, and after standing for 72 hours, a small amount of cotton-like precipitates will be generated in the zinc dipping solution. After 96 hours, the zinc dipping solution will Obviously precipitates were produced; when the content ratios of zinc oxide to sodium hydroxide were 1:15, 1:20, 1:25, after standing for more than 168 hours, no precipitate appeared in the zinc dipping solution. In this embodiment, when the zincation reaction is considered, the passive oxide thin film reaction of the substrate 10 dissolves the hydroxide ions in the zincation solution, but it will reduce the stability of the zincation solution and increase the subsequent processing cost. As the optimal value of the present invention, the ratio of the content of zinc oxide to sodium hydroxide is 1:20. Among them, 10 g / L of zinc oxide and 200 g / L of sodium hydroxide are used as the experimental parameters of this example, but it is not limited to this. this.
為了提升浸鋅液的穩定性，本發明於浸鋅液中額外添加錯合劑及安定劑，值得說明的是，錯合劑的含量對浸鋅液的穩定性有明顯的影響，本發明實施例，錯合劑可為酒石酸鉀鈉、葡萄糖酸鹽；可用來與浸鋅液中的微量元素執行錯合反應，安定劑主要用來穩定浸鋅層20的晶格結構；同時還可提升浸鋅層20的抗腐蝕性能，安定劑與錯合劑間的含量比例為1：10至7：40，其中，1g/L至7g/L 的安定劑與10g/L至40g/L的錯合劑係作為本實施例之實驗參數，但不限於此，藉以穩定及優化基材10表面形成浸鋅層20的功效。In order to improve the stability of the zincating solution, the present invention additionally adds a complexing agent and a stabilizer to the zincating solution. It is worth noting that the content of the complexing agent has a significant effect on the stability of the zincating solution. In the embodiment of the present invention, The complexing agent can be potassium sodium tartrate and gluconate; it can be used to perform a complexing reaction with trace elements in the zinc dipping solution. The stabilizer is mainly used to stabilize the lattice structure of the zinc dipping layer 20; at the same time, it can also improve the zinc dipping layer 20 The anti-corrosion performance, the content ratio between the stabilizer and the complexing agent is 1:10 to 7:40, of which the stabilizer of 1g / L to 7g / L and the complexing agent of 10g / L to 40g / L are used as the implementation The experimental parameters of the example are not limited thereto, thereby stabilizing and optimizing the effect of forming the zinc impregnation layer 20 on the surface of the substrate 10.
後續，進一步探討浸鋅液的反應溫度及反應時間的影響，其中，浸鋅液的反應溫度影響氧化鋅的溶解程度，於本實施例中，反應溫度不高於30℃，較佳者為20℃至30℃，使基材10表面可得到披覆完整的浸鋅層20，而當反應溫度為40℃時，基材10開始出現明顯的點狀腐蝕，且鋅的沉積明顯變少；在50℃時，已無法得到完整的浸鋅層20。Subsequently, the effect of the reaction temperature and reaction time of the zinc immersion solution is further discussed. Among them, the reaction temperature of the zinc immersion solution affects the degree of dissolution of zinc oxide. In this embodiment, the reaction temperature is not higher than 30 ° C, preferably 20 ℃ to 30 ℃, the surface of the substrate 10 can obtain a complete zinc coating layer 20, and when the reaction temperature is 40 ° C, the substrate 10 begins to show obvious pitting corrosion, and zinc deposition is significantly reduced; At 50 ° C, a complete zinc-impregnated layer 20 is no longer available.
而且，浸鋅一開始是由點狀的鋅粒所構成，隨時間的增加逐漸形成網狀組織，直到在基材10表面披覆形成浸鋅層20。由實驗結果，當基材10的浸鋅時間為20秒，基材10表面已完全覆蓋有浸鋅層20，且浸鋅時間持續達到50秒時，浸鋅層20的晶粒逐漸變大。因此，本發明為確保基材10表面能完全覆蓋且獲得結構細緻的浸鋅層20，是故，浸鋅時間較佳為30秒至40秒，且浸鋅層20的厚度為介於10奈米至25奈米。In addition, the zinc impregnation is initially composed of spot-shaped zinc particles, and a reticular structure is gradually formed with time, until the surface of the substrate 10 is coated to form a zinc impregnation layer 20. From the experimental results, when the zincation time of the substrate 10 is 20 seconds, the surface of the substrate 10 is completely covered with the zincation layer 20, and when the zincation time continues to reach 50 seconds, the grain size of the zincation layer 20 gradually increases. Therefore, in the present invention, in order to ensure that the surface of the substrate 10 can be completely covered and obtain a fine structured zincation layer 20, the zincation time is preferably 30 seconds to 40 seconds, and the thickness of the zincation layer 20 is between 10 nanometers. Meters to 25 nanometers.
熱擴散步驟S2：接著，改質後之基材10置於熱處理環境中，並加熱介於100℃至400℃間，加熱時間為1小時，使浸鋅層20之鋅粒受熱擴散至基材10。值得說明的是，熱擴散步驟S2主要係探討藉由不同的熱處理溫度來進行鋅元素的固-固態擴散滲，使基材10表面形成具有附著性佳且質地較耐腐蝕之浸鋅層20結構，因此，本實施例之熱處理溫度由100℃分別加溫至200℃、300℃及400℃，加熱時間為1小時。 表2熱處理溫度對浸鋅層20的影響統計表
經由實驗證實，當熱處理溫度低於300℃時，並未能使鋅粒有效擴散至基材10內，而當熱處理溫度高於300℃時，浸鋅層20的腐蝕電位反而降低，顯而降低浸鋅層20的耐腐蝕性。因此，為了得到穩定且耐腐蝕的浸鋅層20，除了考慮耐腐蝕性，也需考量其電鍍前活化製程的可行性，故本實施例之熱處理溫度較佳為300℃。It has been confirmed by experiments that when the heat treatment temperature is lower than 300 ° C, zinc particles cannot be effectively diffused into the substrate 10, and when the heat treatment temperature is higher than 300 ° C, the corrosion potential of the zinc-impregnated layer 20 is reduced, which significantly decreases. Corrosion resistance of the zinc-impregnated layer 20. Therefore, in order to obtain a stable and corrosion-resistant zinc-impregnated layer 20, in addition to considering corrosion resistance, the feasibility of the activation process before electroplating needs to be considered. Therefore, the heat treatment temperature in this embodiment is preferably 300 ° C.
鎳鎢電鍍步驟S3：最後，冷卻熱處理後的基材10，將基材10置入於含有檸檬酸鈉、硫酸鎳、鎢酸鈉、氯化銨及溴化鈉之一鎳鎢電鍍處理液執行電鍍作業，其中，鎳鎢電鍍處理液的pH值介於6.5至8.5間，使浸鋅層20遠離基材10之一側形成一鎳鎢電鍍層30。Nickel-tungsten plating step S3: Finally, the heat-treated substrate 10 is cooled, and the substrate 10 is placed in a nickel-tungsten plating treatment solution containing one of sodium citrate, nickel sulfate, sodium tungstate, ammonium chloride, and sodium bromide. In the electroplating operation, the pH value of the nickel-tungsten plating treatment liquid is between 6.5 and 8.5, so that the zinc-impregnated layer 20 is away from one side of the substrate 10 to form a nickel-tungsten plating layer 30.
硫酸鎳(NiSO 4 ．6H 2O)，係用來提供鎳離子的來源，鎳離子在pH 值較高的時候易形成氫氧化鎳(Ni(OH) 2)，因此會使得電鍍液不穩定，所以需調整pH 值及加入錯合劑讓鎳離子能夠在鍍液中穩定存在，於本實施例中，硫酸鎳的濃度為0.06M。 Nickel (NiSO 4. 6H 2 O) of sulfuric acid, based for providing a source of nickel ions, nickel ions is easy to form nickel hydroxide (Ni (OH) 2) at high pH when the plating solution so therefore unstable, Therefore, it is necessary to adjust the pH value and add a complexing agent so that nickel ions can stably exist in the plating solution. In this embodiment, the concentration of nickel sulfate is 0.06M.
鎢酸鈉(Na 2WO 4 ．6H 2O)，係用來提供鎢離子的來源，鎢酸根在pH 值較低的時候易形成氧化物(WO3、W2O5)沉澱，因此會使得電鍍液不穩定，所以需調整pH 值與加入錯合劑讓鎢離子能夠在鍍液中穩定存在，於本實施例中，鎢酸鈉的濃度為0.18M。 Sodium tungstate (Na 2 WO 4. 6H 2 O), tungsten-based source for providing ions, tungstate easy to form an oxide when a lower pH (WO3, W2O5) precipitated, therefore such that the plating solution unstable Therefore, it is necessary to adjust the pH value and add a complexing agent so that tungsten ions can stably exist in the plating solution. In this embodiment, the concentration of sodium tungstate is 0.18M.
檸檬酸鈉(Na 3C 6H 8O 7 ．2H 2O)，為電鍍液中鎳離子和鎢離子之錯合劑，使兩種主鹽離子皆能在鍍液中產生鎳鎢共鍍前驅物，於本實施例中，檸檬酸鈉的濃度為0.5M。 Sodium citrate (Na 3 C 6 H 8 O 7. 2H 2 O), the plating solution is nickel ions and tungsten ions of the complexing agent, so that two kinds of main salt ions generated have encountered the CPC in the bath a nickel-plated tungsten precursor In this embodiment, the concentration of sodium citrate is 0.5M.
氯化銨(NH 4Cl)，由銨鹽分解而出的氨(NH 3)亦能和鎳離子錯合形成鎳離子錯合物，進而增加電鍍的電流效率，於本實施例中，氯化銨的濃度為0.5M。 Ammonium chloride (NH 4 Cl), ammonia (NH 3 ) decomposed from ammonium salts can also be combined with nickel ions to form nickel ion complexes, thereby increasing the current efficiency of electroplating. In this embodiment, the chloride The concentration of ammonium was 0.5M.
溴化鈉(NaBr)，作用為提高溶液的導電度，降低電鍍時在溶液中的電阻，於本實施例中，溴化鈉的濃度為0.5M。Sodium bromide (NaBr) is used to improve the conductivity of the solution and reduce the resistance in the solution during electroplating. In this embodiment, the concentration of sodium bromide is 0.5M.
另外，鎳鎢電鍍處理液更包含一pH緩衝劑及一表面活性劑，值得說明的是，pH緩衝劑係為硼酸，可減小電鍍過程中水分子電解，進而降低鎳鎢電鍍處理液解離的H +與OH -濃度變化，其中，pH緩衝劑的濃度為0.15M。 In addition, the nickel-tungsten plating treatment liquid further includes a pH buffer and a surfactant. It is worth noting that the pH buffer is boric acid, which can reduce the electrolysis of water molecules during the electroplating process, thereby reducing the dissociation of the nickel-tungsten plating treatment liquid. H + and OH - concentration, wherein the concentration of pH buffer is 0.15M.
表面活性劑係為十二烷基硫酸鈉，係一種陰離子性表面活性劑，可以降低基材10和鎳鎢電鍍處理液間的表面張力，使鎳鎢電鍍處理液濕潤基材10，得以防止基材10表面出現針孔，進而降低基材10的孔隙率，其中，表面活性劑的濃度為0.57μM。The surfactant is sodium lauryl sulfate, which is an anionic surfactant, which can reduce the surface tension between the substrate 10 and the nickel-tungsten plating treatment solution, and make the nickel-tungsten plating treatment solution wet the substrate 10 to prevent the substrate Pinholes appeared on the surface of the material 10, thereby reducing the porosity of the substrate 10. The concentration of the surfactant was 0.57 μM.
特別說明的是，鎳鎢電鍍處理液中各成分的濃度配比係作為本實施例之實驗參數，並不限於此。It is specifically noted that the concentration ratio of each component in the nickel-tungsten plating treatment liquid is used as an experimental parameter of this embodiment, and is not limited thereto.
進一步說明，鎳鎢電鍍處理液中鎳離子之穩定離子態的pH值介於pH6至pH9之間，而鎢離子之穩定離子態的pH值介於pH4至pH7之間，其中，當鎳鎢電鍍處理液中pH值大於9時，鎳離子會形成氫氧化鎳[Ni(OH)2]，反而會降低鎳鎢電鍍處理液執行電鍍的穩定度，當鎳鎢電鍍處理液中pH值低於4時，鎢離子會形成氧化鎢(WO3、W2O5)，同時也會影響鎳鎢電鍍處理液執行電鍍的穩定度，因此，經由上述結果，鎳鎢電鍍處理液之pH值較佳者為介於5至8之間(隨錯合劑的選用會有所改變)。To further explain, the pH value of the stable ionic state of nickel ions in the nickel-tungsten plating treatment solution is between pH 6 and pH 9, and the pH value of the stable ionic state of tungsten ions is between pH 4 and pH 7; When the pH value in the treatment solution is greater than 9, nickel ions will form nickel hydroxide [Ni (OH) 2], but it will reduce the stability of electroplating in the nickel-tungsten plating treatment solution. When the pH value in the nickel-tungsten plating treatment solution is lower than 4 At the same time, tungsten ions will form tungsten oxide (WO3, W2O5), and it will also affect the stability of the plating process of the nickel-tungsten plating treatment solution. Therefore, according to the above results, the pH value of the nickel-tungsten plating treatment solution is preferably between 5 and 5. To 8 (it will change with the choice of the mixture).
本發明進一步探討鎳鎢電鍍處理液之pH值的電鍍效率，因此，本實施例將基材10分別執行pH6.5、7.5及8.5的電鍍實驗測試。 表3係為鎳鎢電鍍處理液之pH值差異對應鎢含量的統計表
依據表3得知，鎳鎢電鍍處理液在pH6.5及電流密度3A/dm 2操作條件下，鎳鎢電鍍層30測得之最高鎢含量為52.95(wt%)，而在pH8.5及電流密度3A/dm 2操作條件下，鎳鎢電鍍層30測得之最高鎢含量為36.9(wt%)，顯然，鎳鎢電鍍處理液在相同操作條件下，僅改變pH值為6.5、7.5、8.5的差異，經銳意實驗發現，隨著pH值的上升鎢含量明顯呈現下降的趨勢，具體來說，pH6.5與pH8.5所測得鎳鎢電鍍層30之鎢含量相差高達30%，藉此可見鎳鎢電鍍處理液之pH值對鎳鎢鍍層中鎢含量的影響極大，是極為重要的控制參數。 According to Table 3, under the operating conditions of pH 6.5 and current density 3A / dm 2 of the nickel-tungsten plating treatment solution, the highest tungsten content measured by the nickel-tungsten plating layer 30 is 52.95 (wt%). Under the operating conditions of current density 3A / dm 2 , the highest tungsten content measured by the nickel-tungsten plating layer 30 is 36.9 (wt%). Obviously, under the same operating conditions, the nickel-tungsten plating treatment solution only changes the pH values of 6.5, 7.5, The difference of 8.5 was determined through intensive experiments. As the pH value rises, the tungsten content obviously shows a downward trend. Specifically, the difference between the tungsten content of the nickel-tungsten plating layer 30 measured at pH 6.5 and pH 8.5 is as high as 30%. It can be seen that the pH value of the nickel-tungsten plating treatment liquid has a great influence on the tungsten content in the nickel-tungsten plating layer, and is an extremely important control parameter.
後續，以能量散佈光譜儀(EDS)對鎳鎢電鍍層30進行定量成份分析。特別說明的是，電流效率計算是根據鎳鎢電鍍層30重量乘以各元素所佔之重量百分比後，得到鍍層各組成元素之重量，計算出還原成金屬態鎳和鎢用的電量，將各成份之莫耳數乘以所用之電量再除以電鍍時所流通的總電量，即為電鍍鎳鎢合金的電流效率。Subsequently, a quantitative composition analysis is performed on the nickel-tungsten plating layer 30 with an energy dispersive spectrometer (EDS). In particular, the current efficiency calculation is based on the weight of the nickel-tungsten plating layer 30 times the weight percentage of each element, and then the weight of each component of the plating layer is obtained. The amount of electricity used to reduce the metal to nickel and tungsten is calculated. The mole number of the component is multiplied by the amount of electricity used and then divided by the total amount of electricity flowing during plating, which is the current efficiency of the electroplated nickel-tungsten alloy.
本實驗將基材10置於相同電流密度下(3A/dm 2)，測試不同的pH值(pH6.5、7.5、8.5)所得到的鎢離子與鎳離子各別的含量(wt.%)，並且測量電鍍前後間所精密稱重得到的結果，以計算其在3A/dm2 的電流密度下與不同的pH值之沉積速率及電流效率。 In this experiment, the substrate 10 was placed under the same current density (3A / dm 2 ), and the respective contents of tungsten ions and nickel ions (wt.%) Obtained at different pH values (pH 6.5, 7.5, 8.5) were tested. , And measure the results obtained by precision weighing before and after plating to calculate its deposition rate and current efficiency at a current density of 3A / dm2 and different pH values.
電流效率計算公式如下： The current efficiency calculation formula is as follows:
其中
W
Ni 和
W
W 分別代表鎳和鎢在陰極上析出的重量，同時假設還原1個鎢酸根需要6個電子，而陰極電流效率未達到100%因素，於還原過程中伴隨著氫氣的生成，使得陰極電鍍效率變差。 表4係為pH值對沉積效率及電流效率的統計表
請配合參閱圖3及表4所示，當鎳鎢電鍍處理液之pH值為6.5時，電流效率僅為6.28%，沉積速率為146.66μg/h*dm 2；當pH值為7.5時，電流效率為28.08%，沉積速率為653.33μg/h*dm 2；當pH值為8.5時，電流效率高達到45.58%，沉積速率為1056.11μg/h*dm 2，顯而得知，鎳鎢電鍍處理液在pH6.5及pH8.5間的電流效率與沉積速率相差將近7倍。 Please refer to Figure 3 and Table 4. When the pH value of the nickel-tungsten plating treatment solution is 6.5, the current efficiency is only 6.28%, and the deposition rate is 146.66 μg / h * dm 2 ; when the pH value is 7.5, the current The efficiency is 28.08%, the deposition rate is 653.33μg / h * dm 2 ; when the pH value is 8.5, the current efficiency is as high as 45.58%, and the deposition rate is 1056.11μg / h * dm 2. It is obvious that the nickel-tungsten plating treatment The current efficiency of the liquid between pH 6.5 and pH 8.5 is nearly 7 times different from the deposition rate.
而且，操作參數pH值控制在7.5及8.5之間，且電流密度操作參數控制在3A/dm 2至5A/dm 2得到之鍍層結合力，經百格測試及冷熱衝擊試驗其合格率都可達80%以上，且鎳鎢電鍍層30之鍍態硬度約在550HV至650HV。 In addition, the operating parameter pH value is controlled between 7.5 and 8.5, and the current density operating parameter is controlled between 3A / dm 2 to 5A / dm 2. The pass rate of the coating is 100% and the cold and hot shock tests can pass the pass rate. Above 80%, and the hardness of the nickel-tungsten plating layer 30 is about 550HV to 650HV.
另外，請參閱圖4及圖5A及圖5B所示，本發明又一實施例中，於浸鋅步驟S1之前更包含一前處理步驟S0，用來事先優化平坦基材10之表面結構，有利於提升浸鋅步驟S1及鎳鎢電鍍步驟S3中溶解釋放的金屬，可完全披覆於基材10表面。In addition, please refer to FIG. 4 and FIG. 5A and FIG. 5B. In another embodiment of the present invention, the zincation step S1 further includes a pre-treatment step S0 to optimize the surface structure of the flat substrate 10 in advance, which is advantageous. The metal dissolved and released in the step of ascending zinc dipping step S1 and the nickel-tungsten plating step S3 can completely cover the surface of the substrate 10.
前處理步驟S0：將基材10執行熱脫脂、超音波脫脂及活化作業的處理流程，值得說明的是，熱脫脂及超音波脫脂，主要係去除基材10表面上的污物及油脂，若基材10表面未能完全除去污物及油脂時，在後續執行浸鋅步驟S1及鎳鎢電鍍步驟S3時，會影響基材10的結晶成長，反而會降低基材10表面披覆金屬的效率。Pre-processing step S0: The process flow of performing thermal degreasing, ultrasonic degreasing, and activating operations on the substrate 10. It is worth noting that thermal degreasing and ultrasonic degreasing mainly remove dirt and grease on the surface of the substrate 10. When dirt and grease are not completely removed from the surface of the substrate 10, the subsequent crystallizing step S1 and nickel-tungsten plating step S3 will affect the crystal growth of the substrate 10, but will reduce the efficiency of coating the surface of the substrate 10 with metal. .
活化作業，主要係用來活化基材10的晶格結構，有利提升基材10的電鍍品質，其中，本實施例將活化分為酸蝕活化及鹼蝕活化。The activation operation is mainly used to activate the lattice structure of the substrate 10, which is beneficial to improve the plating quality of the substrate 10. In this embodiment, the activation is divided into acid etching activation and alkaline etching activation.
「酸蝕活化」，係運用硫酸溶液(H 2SO 4)清洗活化基材10，能夠提升基材10表面潔淨，雖然透過酸蝕活化可能會造成基材10表面產生氧化物的薄膜，但在後續浸鋅步驟S1中，可透過氫氧化鈉(NaOH)去除氧化物的薄膜，不用額外增加去除氧化物薄膜的處理步驟；「鹼蝕活化」，係運用氫氧化鈉溶液(NaOH)活化處理基材10，但鹼蝕活化會使基材10的表面形成氫氧化物的薄膜，此氫氧化物的薄膜會影響後續電鍍的效率及品質，因此需再增加一道處理步驟以去除薄膜。 "Acid etching activation" is the use of sulfuric acid solution (H 2 SO 4 ) to clean and activate the substrate 10, which can improve the cleanliness of the surface of the substrate 10. Although activation by acid etching may cause oxide films on the surface of the substrate 10, In the subsequent zinc leaching step S1, the oxide film can be removed through sodium hydroxide (NaOH) without additional processing steps for removing the oxide film; "Alkali etching activation" is the use of sodium hydroxide solution (NaOH) to activate the treatment group Material 10, but the alkaline etching activation will cause a thin film of hydroxide on the surface of the substrate 10, and this thin film of hydroxide will affect the efficiency and quality of subsequent electroplating, so an additional processing step is required to remove the thin film.
因此，本發明人為了有效活化基材10的表面，因此將基材10分別進行酸蝕活化及鹼蝕活化的實驗，探討基材10經過酸蝕活化及鹼蝕活化後，表面會有何種變化。 表5酸蝕/鹼蝕操作條件表
請配合圖5A、圖5B及上述表5所示，當基材10浸置於4.7M的硫酸溶液中進行酸蝕活化、活化溫度為25℃、時間為50秒，顯然發現，使基材10的表面呈現平坦且無明顯不良物的效果，達到有效優化基材10的表面晶核結構的功效，如圖5A所示；換言之，當基材10浸置於1.5M的氫氧化鈉溶液中進行鹼蝕活化、活化溫度為60℃、時間為50秒，結果發現基材10表面反而形成有結構不平整的薄膜，因此，經實驗證實，基材10經由酸蝕活化相較於鹼蝕活化，更能夠優化基材10表面結構的效果，進而達到有利於提升浸鋅步驟S1及鎳鎢電鍍步驟S3中溶解釋放的金屬，可完全披覆於基材10表面的功效。Please refer to FIG. 5A, FIG. 5B, and Table 5 above. When the substrate 10 is immersed in a 4.7M sulfuric acid solution for acid etching activation, the activation temperature is 25 ° C., and the time is 50 seconds. The surface of the substrate 10 has the effect of being flat and having no obvious objections, and has the effect of effectively optimizing the surface nucleus structure of the substrate 10, as shown in FIG. 5A. In other words, when the substrate 10 is immersed in a 1.5M sodium hydroxide solution Alkali etching is activated, the activation temperature is 60 ° C, and the time is 50 seconds. As a result, it is found that the surface of the substrate 10 is formed with a film with an uneven structure. Therefore, it is confirmed by experiments that the activation of the substrate 10 through acid etching is more active than alkali etching. The effect of optimizing the surface structure of the substrate 10 can be further achieved, thereby achieving the effect that the metals dissolved and released in the zinc dipping step S1 and the nickel-tungsten plating step S3 can be completely covered on the surface of the substrate 10.
藉此，本發明具有以下優點：With this, the present invention has the following advantages:
1.本發明的處理流程快速，而且運用鎳鎢電鍍方式具有環保、無汙染的效果，還可提升產品高溫耐磨耗的功效。1. The treatment process of the invention is fast, and the use of nickel-tungsten plating method has the effects of environmental protection and pollution-free, and can also improve the effect of high temperature wear resistance of the product.
2.經本實驗研究，於浸鋅液中添加安定劑，達到有效提升浸鋅層20的化學耐受性，而且，透過熱擴散步驟S2，更進一步提升浸鋅層20的化學耐受性，進而穩定浸鋅層20的結構，有利於基材10表面完整電鍍鎳鎢電鍍層30的效果。2. Through this experimental study, adding a stabilizer to the zinc leaching solution can effectively improve the chemical resistance of the zinc leaching layer 20, and further, through the thermal diffusion step S2, the chemical resistance of the zinc leaching layer 20 is further improved, and further Stabilizing the structure of the zinc-impregnated layer 20 is beneficial to the effect of complete electroplating of the nickel-tungsten plating layer 30 on the surface of the substrate 10.
3.而且研究發現，鎳鎢電鍍層30中的鎢含量明顯受到pH值的影響，具體來說，在相同的電鍍條件下，pH值的差異影響鎢含量高達30%以上。因此，本發明經銳意實驗獲得，鎳鎢電鍍處理液的pH值為7.5~8.5之間，電流密度在3A/dm 2~5A/dm 2，所獲得的鎳鎢電鍍層30之鎢含量均能達到45%以上，同時電流效率也能達到30~40%之間，鎳鎢電鍍層30之鍍態硬度約在550HV至650HV，且結合力測試良率也在80%以上。 3. Moreover, it was found that the tungsten content in the nickel-tungsten plating layer 30 is significantly affected by the pH value. Specifically, under the same plating conditions, the difference in pH value affects the tungsten content by more than 30%. Therefore, the present invention has obtained through intensive experiments that the pH value of the nickel-tungsten plating treatment solution is between 7.5 and 8.5, and the current density is 3A / dm 2 to 5A / dm 2. The tungsten content of the obtained nickel-tungsten plating layer 30 can be all It can reach more than 45%, and the current efficiency can reach 30 ~ 40%. The hardness of the nickel-tungsten plating layer 30 is about 550HV to 650HV, and the yield of the binding force test is also more than 80%.
藉此以上所舉實施例僅用以說明本發明而已，非用以限制本發明之範圍。舉凡不違本發明精神所從事的種種修改或變化，俱屬本發明意欲保護之範疇。The above-mentioned embodiments are only used to illustrate the present invention, and are not intended to limit the scope of the present invention. Various modifications or changes which do not violate the spirit of the present invention belong to the scope of the present invention.
S0‧‧‧前處理步驟S0‧‧‧Pre-processing steps
S1‧‧‧浸鋅步驟 S1‧‧‧zinc impregnation step
S2‧‧‧熱擴散步驟 S2‧‧‧ Thermal diffusion step
S3‧‧‧鎳鎢電鍍步驟 S3‧‧‧Ni-Tungsten Plating Steps
10‧‧‧基材 10‧‧‧ Substrate
20‧‧‧浸鋅層 20‧‧‧ Zinc Impregnation Layer
30‧‧‧鎳鎢電鍍層 30‧‧‧ nickel-tungsten plating
圖1係為本發明之步驟流程架構圖。 圖2係為本發明之基材結構剖面示意圖。 圖3係為本發明於鎳鎢電鍍步驟之電流效率統計圖。 圖4係為本發明又一實施例之步驟流程架構圖。 圖5A係為本發明於前處理步驟之基材電子分析掃描圖(一)，表示利用酸蝕活化處理基材的表面。 圖5B係為本發明於前處理步驟之基材電子分析掃描圖(二)，表示利用鹼蝕活化處理基材的表面。FIG. 1 is a flowchart of steps of the present invention. FIG. 2 is a schematic cross-sectional view of a substrate structure according to the present invention. FIG. 3 is a current efficiency statistics chart of the nickel-tungsten plating step of the present invention. FIG. 4 is a flowchart of steps in another embodiment of the present invention. FIG. 5A is a scanning image (1) of the substrate for electronic analysis in the pre-processing step of the present invention, which shows that the surface of the substrate is treated by acid etching activation. FIG. 5B is a scanning image (II) of the substrate for electronic analysis in the pre-processing step of the present invention, which shows that the surface of the substrate is activated by alkali etching.
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| TW200613585A (en) * | 2004-09-02 | 2006-05-01 | Micron Technology Inc | Selective nickel plating of aluminum, copper, and tungsten structures |
| TW201040323A (en) * | 2009-05-04 | 2010-11-16 | Neil Metals Suzhou Co Ltd | Method for plating copper on aluminum or aluminum alloy substrate |
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| TW201943890A (en) | 2019-11-16 |
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