What Does Transference Mean?
Transference is the act of moving something from one place to another. It is used in electrochemistry for measuring charge transfer or ion transfer. Selective transference is used to purify compounds. Transference number or transport number is used to measure the transference of ions.
Transference is also known as conveyance or transfer.
Corrosionpedia Explains Transference
In electrochemistry, transference is the act of transferring ions or charge during electrolysis. It is measured by transference number. Transference number of an ion is the fraction of the total current that is carried by that ion during electrolysis. Transference number is also known as transport number.
Different ions carry different fractions of the current because different ions move at different speeds under the same potential gradient. In general, a cation and an anion differ in the amount of current they can carry during electrolysis. Therefore, transference numbers are a fraction of the total current carried by an ion.
Transference number is always equivalent to the ratio between the velocity or mobility of an ion and the sum of the velocities of cation and anion. This is described as a characteristic, which is dependent on:
- Mobilities of ions
- Temperature of ions in an electrolytic solution
It is useful in corrosion, in that the ion-selectivity of corrosion rust is normally estimated in terms of transference number of migrating ions through the rust.
Selective transference of specific ions can be achieved through using membranes for purifying acids. For example, a liquid membrane allows a selective transference of phosphate ion and avoids the transference of cations and impurities, giving a solution purified of phosphoric acid.
In adhesive wear, wear by transference of material from one surface to another occurs during relative motion due to a process of solid-phase welding. Particles that are removed from one surface are either permanently or temporarily attached to the other surface.