1364865 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種具有表面改質層之鋁合金雙極板及其 製法，其兼具抗腐錄佳、導電性佳、成本低及加工容易等優 點。 【先前技術】 -般質子交換薄膜燃料電池(Pr〇t〇n Exchange此此聰 Fuel Cell ’以τ_Ρ_)所使狀雙極板通常係以石墨來 當材料’利用銑床於平板表面銑出平行或是各種形狀之氣流道 溝槽’該石墨雙極板雖具有抗腐錄及—定之導電度，但也存 在加工不《、赌紐高、成本高(佔聰g域本約_、 體積大及重量較重等缺點。就板材脆性高而言，若燃料電池之 尺寸較小，流場板之厚度亦會縮小，然而，由於石墨之脆性高， 厚度有-定的限制，因此，若厚度不足，會產生裂紋、甚至斷 裂。 右將石墨雙極板改由較便宜之金屬板來替代（參閱第一、 第Γϋ第二表）’成本會大大降低，但蘭c於使用時會有離 子微里洛解於支成水中，使金屬雙極板處於腐餘環境中，造成 金屬雙極紐生腐轉離能降低。 5 1364865 第二表1364865 IX. Description of the Invention: [Technical Field] The present invention relates to an aluminum alloy bipolar plate having a surface modification layer and a preparation method thereof, which have good corrosion resistance, good electrical conductivity, low cost and easy processing Etc. [Prior Art] - The proton exchange membrane fuel cell (Pr〇t〇n Exchange, this Cong Fuel Cell 'with τ_Ρ_) is usually made of graphite as the material 'milled on the flat surface of the flat surface by milling or It is a kind of airflow channel groove of various shapes. Although the graphite bipolar plate has anti-corrosion record and constant conductivity, it also has no processing, high stakes, high cost (accounting for Cong G domain, large volume and The disadvantages of heavy weight, etc. In terms of high brittleness of the plate, if the size of the fuel cell is small, the thickness of the flow field plate will also be reduced. However, since the brittleness of graphite is high, the thickness has a certain limit, and therefore, if the thickness is insufficient, Cracks may occur, or even break. The graphite bipolar plate is replaced by a cheaper metal plate (see the first, second, second table). The cost will be greatly reduced, but the blue c will have ion micro during use. Lilo is dissolved in water, so that the metal bipolar plate is in a corrosive environment, which causes the metal bipolar rot to turn off. 5 1364865 Second Table
第一表 各種商用金屬腐餘效率的比較表 材料 鋁 鎳 金 石 墨 鶴 鎳 磷 銅 316不銹 鋼 腐蝕速率 (//m/year) -250 >1000 <15 <15 <100 <30 >500 <100 各種商用金屬電阻率的比較表 材料 鋁 鎳 金 石 墨 鎢 鎳磷 銅 316不錄鋼 電阻率 (^ ω·cm) 2.45 7.24 2.4 12 5.5 27-45 1.72 72 第三表 石墨與鋁合金金屬雙極板的比較表 材料 重量（g) 厚度（) 體積（CW3) 材料成本 ($) $/kW 石墨 137.9 0.23 77 14.48 89.11 鋁合金 49.8 0.1 18.4 0.44 「^.71 一般使用表面改質來改善此問題，而其中以鎳磷鍍層抗蝕效 果較佳，但鎳磷合金本身熱穩定性不佳，若經熱處理後，其抗腐 蝕性大大降低(請參閱第四表），故，採用鎳磷鍍層之習知技術， 無法同時擁有熱穩定性佳及抗腐蝕性佳之特性，不適用於燃料電 池之應用上。 6 1364865 第四表 不同錄基合金之熱穩定性及抗餘性的比較表 —~^^項目 鎳鱗合金金屬雙 鎳钥填合金金屬 寺徵♦ 極板 雙極板 有 無 熱穩定性 差 優 腐ϋ速率（退火前、 0. 034 0.041 腐蝕速率（退火後） 0.96 0.069The first table of various commercial metal corrosion efficiency comparison table material aluminum nickel gold graphite crane nickel phosphorus copper 316 stainless steel corrosion rate (/ / m / year) -250 >1000 <15 <15 <100 <30 > ;500 <100 comparison of various commercial metal resistivity materials aluminum nickel gold graphite tungsten nickel phosphorus copper 316 non-recorded steel resistivity (^ ω · cm) 2.45 7.24 2.4 12 5.5 27-45 1.72 72 third table graphite and aluminum Comparison of Alloy Metal Bipolar Plates Material Weight (g) Thickness () Volume (CW3) Material Cost ($) $/kW Graphite 137.9 0.23 77 14.48 89.11 Aluminum Alloy 49.8 0.1 18.4 0.44 "^.71 General Surface Modification This problem is improved, and the nickel-phosphorus coating has better corrosion resistance, but the nickel-phosphorus alloy itself has poor thermal stability. If it is heat-treated, its corrosion resistance is greatly reduced (please refer to the fourth table), so nickel is used. The conventional technology of phosphorous coating cannot have the characteristics of good thermal stability and good corrosion resistance, and is not suitable for fuel cell applications. 6 1364865 Comparison Table of Thermal Stability and Residual Resistance of Different Recording Base Alloys in the Fourth Table —~^^ project nickel scale Duplex nickel metal alloy filler metal temple intrinsic key ♦ plate of the bipolar plate preferably has a poor thermal stability without ϋ corrosion rate (before the annealing, 0.034 0.041 corrosion rate (after annealing) 0.96 0.069
因此’有必要研發新產品，以解決上述缺點及問題。 【發明内容】 本發明之主要目的’在於提供一種表面改質層之鋁合金雙 極板及其製法，其具有抗腐蝕性佳。 本發明之次一目的，在於提供一種表面改質層之鋁合金雙 極板及其製法，其具有導電性佳。Therefore, it is necessary to develop new products to solve the above shortcomings and problems. SUMMARY OF THE INVENTION The main object of the present invention is to provide an aluminum alloy bipolar plate having a surface modification layer and a method for producing the same, which have excellent corrosion resistance. A second object of the present invention is to provide an aluminum alloy bipolar plate having a surface modifying layer and a method for producing the same, which have excellent electrical conductivity.
本發明之又一目的，在於提供一種表面改質層之鋁合金雙 極板及其製法，其具有成本低。 本發明之再一目的，在於提供一種表面改質層之鋁合金雙 極板及其製法，其具有加工容易。 本發明係提供一種表面改質層之鋁合金雙極板及其製 法，其結構部分包括： 一對鋁合金雙極板，每一鋁合金雙極板係具有一内表面及 一外表面’該内表面上設有至少一流道’該對銘合金雙極板分 別具有相反之電的極性； < S ) 7 U04865 由第四表結果可知，熱穩定性差之金屬雙極板，其抗餘性 亦^因受如變差，耻，加人秋元軸，改善_合金熱 二ϋ不佳的缺點，鎳銦磷合金金屬雙極板不僅抗蝕性優異， …穩疋性雜觸合金金屬板高，經受織抗紐變化不大。 另外，由於燃料電池是屬於酸性環境，所以雙極板必須處 長時間腐餘環境巾’因此，必須具備極佳之抗ϋ性，才能延 長燃料電池壽命’由第五表及第四圖結果可知，鎳鉬磷合金（以 第-曲線L2表示)於腐倾境下，具有比錄填合金(以第一面 線L1表示)較好的抗蝕性。 第五表 鱗合金浸泡於硫酸後之腐蝕速率比較表 —--- 不同鎳基合金金屬 ___雙極板 鎳磷合金 鎳名目（10g/L)磷 合金 腐钱電流(A/cm〗） 2.995*10一6 3.375*10-6 2〇hr腐蝕電流 (A/cm^) 5. 2*10-5 1.5*10-5 4〇hr腐蝕電流 _ (A/cmh 8.2*10-4 --- 3·2*10_5 < S ) 10 第六表 不同酸鹼值鎳鉬磷金屬雙極板成分之比較表 酸驗值 Ni P Mo PH7 93.1 4.8 2.1 PH8 92.3 4.5 2.8 PH9 92.5 4.1 3.4 關於前述之前處理是非常重要的，鋁合金表面平整，鋅置 換層才會分布均自，顯沉射會平整，金屬雙極板表面結構 才b平正緻松。鋁合金直接沉積鎳磷合金表面較粗链，結構緻 度-文匆远過鍍層中的缺陷侵蝕底部基材，因此耐蝕 較差’因為結本身氧化電位較鋅大，沒有經過辞置換層，直 沉積鎳基錢層，易丢出電子讓鎳離子還原’造成界面反應快 積速率太决，使内部缺陷變多；反之若經過辞置換處理，: 柯赫絲面的鎳碟鍍層較平整、緻密且無缺陷，所以抗4 減佳，所以’鋅置換層可有效使鎳磷鍍層平整沉積在金， 極扳上。 一 更詳細的說，前處理 精以超音波震顧清洗51n 係先_丙_ 後利用去離蝴魏、、^除表面油脂細物4 然後以去軒水綠，並w _減_俩各1分鐘: 並置入鋅置換液中2分鐘進行鋅置換， 當第一次鋅置換完成後，再以去離子水清洗，並再浸泡氫氧化 鈉與硕酸各0. 5分鐘’並繼續置入鋅置換液1分鐘進行第二次 鋅置換，之後再以去離子水清洗，完成鋅置換活化層。 當然，鉬元素的濃度對鎳鉬磷鍍層結構及抗蝕性具有一定 之〜響，钥元素濃度在5g/L，錄離子還原較快，所以鍍層均 一性差，且表面粗糙；當濃度升至15g/L時，會因為鍍層中鉬 含量過多，造成表面應力過大，使鎳鉬磷鍍層產生龜裂現象， 抗钮性亦變差，結果顯示鎳鉬填合金在鉬元素濃度為 時，可得鍍層合金微粒小，緻密性高，且表面較平整之鍍層， 其抗腐蝕性亦最佳。因此，鉬元素濃度在7· 5〜12·㈤几時是 一較佳之範圍。 另外，由於鉬元素具有極佳之抗蝕性，使得本發明由鎳鉬 鱗所組成之表面改質層只要3〜lG微米厚，即可達到傳統鎳罐 鍍層20〜30微米厚之之抗蝕性，換言之，若要達到相同之抗蝕 能力，本發明之鍍層可以較薄。 由第六表可知，當pH值不同時，其鎳、磷及鉬之比例亦 有所隻化’其pH值為7 ’鎳佔93. lwt%，磷8wt%，铜佔 2.1Wt%，其pH值為8，鎳佔92. 3wt%，磷佔4. 5wt%，鉬佔 2. 8WU ’其pH值為9，鎳4占92. 5wt%，碌佔4. lwt%，銷佔 3. 4wt%。 矣不上所述’本發明之優點及功效可歸納為： [1]抗腐姓性佳。由於本發明採用之鎳磷合金係置入耐火 元素鉬，其形成之表面改質層為鎳鉬磷，該鎳鉬碌係具有良好 的耐腐歸且熱穩定性佳，良好的熱穩定性使該錄闕經過退 火處理後，其抗蝕性變化不大。 [2] 導電性佳。由於本發明係於鋁合金雙極板表面沉積一 奈米晶_金屬該奈米晶態金屬薄膜本身晶粒較細化、 緻密、孔隙較少，導電能力與純金屬差異不大（參閱第二表， 其中’電阻值愈小之金屬，其導電度愈佳）。 [3] 成本低。由第三表可知，本案所採用之鋁合金雙極板 與般石墨雙極板之比較，該銘合金雙極板不但重量輕、厚度 薄、體積小且材料成本低，大大降低製造成本，具有相當大的 市場開發潛力。 [4] 加工容易。一般石墨雙極板體積過於龐大，且氣體流 道加工繁雜，不論是製程或成本，都不符合投資效益，而本發 明之鋁合金雙極板重量輕、厚度薄、體積小，較易於加工，適 合大量生產。 由以上詳細說明，可使熟知本項技藝者明瞭本發明的確可 達成前述目的，實已符合專利法之規定，爰提出發明專利申請。 1364865 【圖式簡單說明】 第圖係本發明之具有表面改質之銘合金雙極板的示意圖 第一圖係本發明之具有表面改質之is合金雙極板之表面改質 層的示意圖 第二圖係本發明之具有表面改質之鋁合金雙極板製法之流程 圖 第四圖係本發明之具有表面改質之鋁合金雙極板與鎳磷合金Still another object of the present invention is to provide an aluminum alloy bipolar plate having a surface modifying layer and a method of producing the same, which are low in cost. Still another object of the present invention is to provide an aluminum alloy bipolar plate having a surface modification layer and a process for producing the same, which are easy to process. The invention provides an aluminum alloy bipolar plate with a surface modifying layer and a manufacturing method thereof, wherein the structural part comprises: a pair of aluminum alloy bipolar plates each having an inner surface and an outer surface The inner surface is provided with at least the first-class roads. The pair of alloy bipolar plates have opposite electrical polarities respectively; <S) 7 U04865 It can be seen from the results of the fourth table that the metal bipolar plates with poor thermal stability have residual resistance. Also ^ because of the change, shame, add people Qiuyuan axis, improve the shortcomings of poor alloy hot dip, nickel indium phosphorus alloy metal bipolar plate not only excellent corrosion resistance, ... stable high-impact alloy metal plate high It is not much change to withstand the weaving resistance. In addition, since the fuel cell is an acidic environment, the bipolar plate must be in a long-term environment. Therefore, it must have excellent resistance to the fuel cell life, as shown in the fifth and fourth figures. The nickel-molybdenum-phosphorus alloy (indicated by the first curve L2) has better corrosion resistance than the recorded alloy (indicated by the first line L1) in the rot. Corrosion rate comparison table of the fifth scale alloy immersed in sulfuric acid---- different nickel-based alloy metal ___ bipolar plate nickel-phosphorus alloy nickel name (10g/L) phosphorus alloy decay money current (A/cm) 2.995*10-6 3.375*10-6 2〇hr corrosion current (A/cm^) 5. 2*10-5 1.5*10-5 4〇hr corrosion current _ (A/cmh 8.2*10-4 -- - 3·2*10_5 < S ) 10 Table 6 Comparison of different pH values of nickel-molybdenum-phosphorus metal bipolar plates. Acid value Ni P Mo PH7 93.1 4.8 2.1 PH8 92.3 4.5 2.8 PH9 92.5 4.1 3.4 Before the foregoing The treatment is very important. The surface of the aluminum alloy is flat, the zinc replacement layer will be distributed, and the surface of the metal bipolar plate will be flat and loose. The aluminum alloy directly deposits the surface of the nickel-phosphorus alloy with a relatively thick chain, and the structure is tempered. The defects in the coating eroded the bottom substrate, so the corrosion resistance is poor. Because the oxidation potential of the junction itself is larger than that of zinc, there is no replacement layer, direct deposition. Nickel-based money layer, easy to throw electrons to reduce nickel ions 'causes the interfacial reaction rate is too fast, so that internal defects become more; if the word is replaced by the replacement, the nickel plate plating of the Koch surface is flat and dense. There is no defect, so the anti-4 is better, so the 'zinc replacement layer can effectively deposit the nickel-phosphorus plating on the gold and the pole. In more detail, the pre-treatment is super-sonic to clean the 51n system first _ _ _ after use to remove the butterfly Wei, ^ remove the surface oil fines 4 and then go to Xuan Shui green, and w _ reduce _ each 1分钟: And placed in the zinc replacement solution for 2 minutes for zinc replacement, after the first zinc replacement is completed, and then washed with deionized water, and then soaked sodium hydroxide and sour acid each 0. 5 minutes ' and continue to set The zinc replacement liquid was introduced into the zinc replacement solution for a second time, and then washed with deionized water to complete the zinc displacement activation layer. Of course, the concentration of molybdenum has a certain resistance to the structure and corrosion resistance of the nickel-molybdenum-phosphorus coating. The concentration of the key element is 5g/L, and the recorded ion reduction is faster, so the uniformity of the coating is poor and the surface is rough; when the concentration is raised to 15g When /L, the surface stress is too large due to excessive molybdenum content in the coating, causing cracking of the nickel-molybdenum-phosphorus coating, and the resistance to the button is also deteriorated. The result shows that the nickel-molybdenum filler alloy can obtain the coating layer when the concentration of molybdenum element is The alloy has small particle size, high compactness, and a flat surface coating, which is also excellent in corrosion resistance. Therefore, the concentration of molybdenum element is a preferred range in the range of 7·5 to 12·(f). In addition, since the molybdenum element has excellent corrosion resistance, the surface modification layer composed of nickel-molybdenum scales of the present invention can reach a conventional nickel can coating layer of 20 to 30 micrometers thick as long as it is 3 to 1 g thick. Sex, in other words, the coating of the present invention can be thinner if the same resistance is achieved. It can be seen from the sixth table that when the pH is different, the ratio of nickel, phosphorus and molybdenum is also reduced to 'the pH value is 7'. The nickel accounts for 93. lwt%, the phosphorus is 8wt%, and the copper accounts for 2.1wt%. 0重量%的销占3。 The pH is 8, the nickel accounted for 92. 3wt%, the phosphorus accounted for 4. 5wt%, the molybdenum accounted for 2. 8WU 'the pH value of 9, the nickel 4 accounted for 92. 5wt%, the accounted for 4. lwt%, the pin accounted for 3. 4wt%. The advantages and effects of the present invention can be summarized as follows: [1] The anti-corruption surname is good. Since the nickel-phosphorus alloy used in the present invention is provided with refractory element molybdenum, the surface modification layer formed thereof is nickel molybdenum phosphorus, and the nickel-molybdenum system has good corrosion resistance and good thermal stability, and good thermal stability is After the annealing process, the corrosion resistance does not change much. [2] Good conductivity. Since the present invention is deposited on the surface of an aluminum alloy bipolar plate, a nanocrystalline crystal is denser, denser, and has fewer pores, and the conductivity is not significantly different from that of the pure metal (see the second Table, where the metal with the smaller resistance value has better conductivity. [3] Low cost. It can be seen from the third table that the alloy bipolar plate used in this case is not only light in weight, thin in thickness, small in volume and low in material cost, but also greatly reduces the manufacturing cost, compared with the ordinary graphite bipolar plate. Considerable market development potential. [4] Easy processing. Generally, the graphite bipolar plate is too bulky, and the gas flow path is complicated to process, and the process or cost is not in accordance with the investment benefit, and the aluminum alloy bipolar plate of the invention is light in weight, thin in thickness, small in size, and easy to process. Suitable for mass production. From the above detailed description, it will be apparent to those skilled in the art that the present invention can be achieved by the present invention, which is in accordance with the provisions of the Patent Law. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a surface modification layer of an alloyed bipolar plate having surface modification according to the present invention. FIG. 2 is a flow chart of a method for preparing an aluminum alloy bipolar plate having surface modification according to the present invention. FIG. 4 is a surface modified aluminum alloy bipolar plate and a nickel phosphorus alloy according to the present invention.
浸泡於硫酸40小時後的示意圖 【主要元件符號說明】 10 IS合金雙極板 11内表面 12外表面 20鎳磷鍍層 41準備基材步驟 43鋅置換步驟Schematic diagram after immersion in sulfuric acid for 40 hours [Description of main components] 10 IS alloy bipolar plate 11 inner surface 12 outer surface 20 nickel phosphorous coating 41 preparation of substrate step 43 zinc replacement step
13流道 30表面改質層 42前處理步驟 44預魏錄構步驟 L1第〆曲線 45置入三元合金鍍液步驟 L2第二曲線13 flow path 30 surface modification layer 42 pre-processing steps 44 pre-week recording step L1 third curve 45 placed into the ternary alloy plating step L2 second curve