本站編輯：杭州達躍機械有限公司發布日期：2020-01-02 21:22 瀏覽次數：
通過采用SEM, XRD、電位一時間曲線、膜重變化等方法詳細研究了促進劑、氟化物、Mn2+, Ni2+, Zn2+, PO4;和Fe2+等對鋁材磷化過程的影響。研究表明:硝酸胍具有水溶性好，用量低，快速成膜的特點，是鋁材磷化的有效促進劑:氟化物可促進成膜，增加膜重，細化晶粒;Mn2+, Ni2+能明顯細化晶粒，使磷化膜均勻、致密并可以改善磷化膜外觀;Zn2+濃度較低時，不能成膜或成膜差，隨著Zn2+濃度增加，膜重增加;PO4含量對磷化膜重影響較大，提高PO4。含量使磷化膜重增加。
鋁及其合金在中性體系中陽極氧化沉積形成類陶瓷非晶態復合轉 化膜的工藝、性能、形貌、成分和結構，初步探討了膜層的成膜過程和機理。 工藝研究結果表明，在Na_2WO_4中性混合體系中，控制成膜促進劑濃度為2.5～3.0g/l， 絡合成膜劑濃度為1.5～3.0g/l，Na_2WO_4濃度為0.5～0.8g/l，峰值電流密度為6～12A/dm~2， 弱攪拌，可以獲得完整均勻、光澤性好的灰色系列無機非金屬膜層。該膜層厚度為 5～10μm，顯微硬度為300～540HV，耐蝕性優異。該中性體系對鋁合金有較好的適應性， 防銹鋁、鍛鋁等多種系列鋁合金上都能較好地成膜。Aluminum casting technology is widely used in modern machinery and industry. Aluminum die casting technology is one of the common manufacturing methods of aluminum casting. In the process of production, there will be some problems. Today, I will introduce the surface treatment method of aluminum die casting.
1. Aluminum phosphating
The effects of accelerants, fluorides, Mn2 +, Ni2 +, Zn2 +, PO4, and Fe2 + on the phosphating process of aluminum were studied in detail by means of SEM, XRD, potential time curve and film weight change. The results show that guanidine nitrate has the characteristics of good water solubility, low dosage and rapid film formation, which is an effective promoter for aluminum phosphating: fluoride can promote film formation, increase film weight and refine grains; Mn2 +, Ni2 + can obviously refine grains, make phosphating film uniform, dense and improve the appearance of phosphating film; when Zn2 + concentration is low, it can not form film or poor film formation, with the increase of Zn2 + concentration, the film weight increases; PO The content of PO4 has a great influence on the weight of phosphating film, and PO4 is increased. The weight of phosphating film increased with the content.
2. Alkaline Electropolishing of aluminum
The basic polishing solution system was studied, and the effects of corrosion inhibitor and viscosity agent on the polishing effect were compared. The basic polishing solution system with good polishing effect was successfully obtained, and the additives that can reduce the operating temperature, prolong the service life of the solution and improve the polishing effect were obtained for the first time. The experimental results show that good polishing effect can be obtained by adding proper additives into NaOH solution. It is also found that the reflectivity of aluminum surface can reach 90% after electropolishing with NaOH solution of glucose under certain conditions. However, due to the unstable factors in the experiment, further research is needed. The feasibility of polishing aluminum in alkaline condition by DC pulse electropolishing is explored. The results show that DC constant voltage electropolishing can achieve the leveling effect, but its leveling speed is slow.
3. Environmental friendly chemical polishing of aluminum and aluminum alloy
It is determined to develop a new environmentally friendly chemical polishing technology based on phosphoric acid and sulfuric acid. The technology should achieve zero NOx emission and overcome the quality defects of previous similar technologies. The key of the new technology is to add some compounds with special functions to the base solution to replace nitric acid. Therefore, it is necessary to analyze the chemical polishing process of aluminum, especially the role of nitric acid. The main function of nitric acid in the chemical polishing of aluminum is to restrain the spot corrosion and improve the brightness of polishing. Combined with the chemical polishing test in pure phosphoric acid and sulfuric acid, it is considered that the special substances added in phosphoric acid and sulfuric acid should be able to inhibit the spot corrosion and slow down the overall corrosion, at the same time, it must have a better leveling and bright effect
4. Electrochemical surface strengthening of aluminum and its alloys
The process, properties, morphology, composition and structure of ceramic like amorphous composite conversion film formed by anodizing of aluminum and its alloy in neutral system were discussed. The results show that in the neutral mixed system of nazhu2wo ﹤ 4, the concentration of film-forming promoter is 2.5-3.0g/l, the concentration of complexing agent is 1.5-3.0g/l, the concentration of nazhu2wo ﹤ 4 is 0.5-0.8g/l, the peak current density is 6-12a / DM ~ 2, and the gray series inorganic non-metallic films with good luster can be obtained by weak stirring. The thickness of the film is 5-10 μ m, the microhardness is 300-540hv, and the corrosion resistance is excellent. The neutral system has good adaptability to aluminum alloy, and film can be formed on various series of aluminum alloy such as antirust aluminum and forged aluminum.