基礎知識

その他 フォーラム自体について、およびその他のカテゴリーに属さないテーマについての討論

Post Treatment of Anodising Layers
常温で使用できるニッケルフリーおよびコバルトフリーの代替品

For post treating anodising layers on aluminium, typically two different technologies are applied, the hot water sealing at 96-100 °C and the cold sealing using reactive salts to plug the pores of the anodic coating. Both applications show major disadvantages. Whereas the hot water sealing is extremely energy consuming due to the mandatory hot process temperature, the low temperature sealing processes typically apply nickel compounds being harmful to the environment. Nickel salts are toxic and carcinogenetic, having irreversible effects on the human body and health. Furthermore, nickel containing waste waters are difficult to treat, especially when also aluminium is present [1]. New nickel-free technologies have been developed accordingly, enabling a low temperature application yielding in major energy savings. The deposition of antisoluble compounds in the pores of the anodizing layer leads to best stability and corrosion protection, exceeding the performance of hot water sealing. The new process solutions as being non-toxic are less risky to store and to handle, assisting the safety at work. Implementing a new photometrical method for analysing the ingredients, process stability and production quality can be improved [2]. In some cases, the pH-resistance of the anodised surface can be enhanced, extending the application field of anodised aluminium. Moreover, the waste water treatment of the rinses is carried out at pH 9–10, hence, can be done mutually with aluminium containing effluents.

SurTec 451 – Chemical Deburring
SurTec Technical Letter 20

Process description of chemical deburring for steel components

Hard Anodising in Practice
SurTec Technical Letter 19

Technical hard anodising is based on physical as well as chemical processes. This complex procedure results from its various interdependent parameters. The following describes its fundamentals and practical use.

Anodisation
SurTec Technical Letter 18

The structure or quality of a material to be anodised and coloured is very important, since this is what a perfect oxide layer and colour depends on. The material can be high-purity aluminium, high-grade aluminium or an aluminium alloy. High-purity aluminium contains practically no other metals (less than 0.05 %), while high-grade aluminium can contain up to 1 % other metals. For certain applications, aluminium is not hard enough on its own and must therefore be alloyed, usually with magnesium, silicon, manganese, copper or zinc. As the percentage of other metals increases, the alloy’s resistance to mechanical stress increases, however its suitability for decorative purposes (colouring) decreases. Colouring itself does not alter the nature of the oxide layer.

Electropolishing
SurTec Technical Letter 17

Process Description for Electrolytic Polishing of Stainless Steel