Corrosion therefore is an
effect of molecular motion, and is one of the modes by which that
motion is converted into and produces electric current.
In accordance with this theory, if we take a thermo-electric pair
consisting of a non-corrodible metal and an electrolyte (the two being
already electro-polar by mutual contact), and heat one of their points
of contact, the molecular motions of the heated end of each substance
at the junction are altered; and as thermo-electric energy in such
combinations usually increases by rise of temperature, the metal and
liquid, each singly, usually becomes more electro polar. In such a
case the unequally heated metal behaves to some extent like two
metals, and the unequally heated liquid like two liquids, and so the
thermo-electric pair is like a feeble chemico-electric one of two
metals in two liquids, but without corrosion of either metal. If the
metal and liquid are each, when alone, thermo-electro-positive, and if,
when in contact, the metal increases in positive condition faster than
the liquid by being heated, the latter appears thermo-electro-negative,
but if less rapidly than the liquid, the metal appears
thermo-electro-negative.
Pages:
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115