Ethnographic Arms & Armour - View Single Post

katana · 24th August 2006, 08:50 PM

The 'sacrifical anode' effect is used on many maritime structures and ships ...Zinc primer (paint) has excellent rust preventative qualities. Zinc protects the iron by cathodic protection, since it is higher on the electrochemical scale than iron and will sacrifice itself to protect the iron, reducing it to the metal and eliminating rust. This phenomenon was noted by Faraday in 1829. If it sacrifices too much, however, the iron is exposed to oxidation, as is sometimes seen with old or damaged galvanized iron.
The purity of the zinc would be important and directly proportional to its effect.....the more pure..the more powerful. This power comes at a price... as its action is stronger (more reactive), it is quicker to be 'used up' and looses mass more rapidly.
If the pommel is pure zinc, it would be highly likely that the sword would have had the pommel replaced several times ...because over a period of time the pommel would have gradually 'melted away'.
I can only assume the pommel is a zinc alloy.... as Lew's and your example have clean, smooth pommels, showing little deteriation.

Africa, has very few mines and produces little zinc (globably).... Zinc would be in very short supply locally.......but the trade routes from India and the Arab states would have made it more accessable.

Hi Ariel, I'm suggesting that in certain climates, with high humidity, condensation forming on the blade would act as a carrier of ions between metals. The effect would most certainly be strongest at the point of contact.
I had a speedboat, the outboard motor made of aluminium, it had a zinc 'scarifial anode' shaped like a fin bolted to it (2 functions..1 item) This zinc 'fin' gradually 'wears' away as it sacrifies itself protecting the motor.

Trim Tab Kit BF25-BF50
Sacrificial anode metal protects the engine from corrosion.

3700952 - $13.59

24th August 2006, 08:50 PM	#16
katana Member Join Date: Jan 2006 Location: Kent Posts: 2,653	The 'sacrifical anode' effect is used on many maritime structures and ships ...Zinc primer (paint) has excellent rust preventative qualities. Zinc protects the iron by cathodic protection, since it is higher on the electrochemical scale than iron and will sacrifice itself to protect the iron, reducing it to the metal and eliminating rust. This phenomenon was noted by Faraday in 1829. If it sacrifices too much, however, the iron is exposed to oxidation, as is sometimes seen with old or damaged galvanized iron. The purity of the zinc would be important and directly proportional to its effect.....the more pure..the more powerful. This power comes at a price... as its action is stronger (more reactive), it is quicker to be 'used up' and looses mass more rapidly. If the pommel is pure zinc, it would be highly likely that the sword would have had the pommel replaced several times ...because over a period of time the pommel would have gradually 'melted away'. I can only assume the pommel is a zinc alloy.... as Lew's and your example have clean, smooth pommels, showing little deteriation. Africa, has very few mines and produces little zinc (globably).... Zinc would be in very short supply locally.......but the trade routes from India and the Arab states would have made it more accessable. Hi Ariel, I'm suggesting that in certain climates, with high humidity, condensation forming on the blade would act as a carrier of ions between metals. The effect would most certainly be strongest at the point of contact. I had a speedboat, the outboard motor made of aluminium, it had a zinc 'scarifial anode' shaped like a fin bolted to it (2 functions..1 item) This zinc 'fin' gradually 'wears' away as it sacrifies itself protecting the motor. Trim Tab Kit BF25-BF50 Sacrificial anode metal protects the engine from corrosion. 3700952 - $13.59 Attached Images Last edited by katana; 24th August 2006 at 09:05 PM.