The authoritative public forum
  for Metal Finishing since 1989
-----

Conductivity question

Q1. How many factors are responsible which affect on conductivity of electrolyte solutions
Q2. Please if you have any idea about the book or paper related to that problem mensioned above so please write down its name.

S. Masood
student - Karachi, Pakistan
2007

---

2007

This question will help me as much as it will help you. Some if not all factors are:

1) Current density applied.
2) Metal concentration of the electrolyte.
3) Temperature of the solution.
4) ph
5) Solution agitation
6) Anode to cathode distance.
7) Anode to cathode ratio.
8) Conducting salts, or acids (throwing power)
9) Buss bar cleanliness and choice eg: s/s, copper, brass.
10) Purity of the solution, absence of organic and inorganic contaminants.
11) Anode configuration - increased surface area.
12) Brightener concentration (if applicable).
13) Rectifier ripple, electrode lead distance.
I'm sure there may be a few more factors, but this is a good start. I'm sure there are books out there that explain the above factors. Good Luck!

Mark Baker
Process Engineer - Syracuse, New York

---

2007

This is from memory, so please make allowances. :)

Each ion has, in aqueous solution, a specific conductivity, and a molar conductivity. The former is independent of concentration. Since each ion is differently sized, and is bound more or less strongly to the water molecules that surround it, each has a different capacity to carry current through a solution, granted an electric field of a given strength. These values, denoted by the Greek letter kappa, are tabulated in reference books.

Conductivity is generally measured by making a conductivity cell (two platinum sheets, coated with platinum black, with a known volume of electrolyte between them) one of the legs in a Wheatstone bridge circuit. An alternating potential of roughly 1000 Hz is applied to the circuit, and a variable resistance adjusted until the resistance of this variable leg of the bridge matches that of the conductivity cell, as indicated by potentiometer null.

Hopefully, this gets you started. Next step: consult a good textbook of physical chemistry, such as "Physical Chemistry" by P.W. Atkins. Largely owing to Dr. Atkins' clear explanations, I got a 'B' in this course.

Good luck!

Dave Wichern
Consultant - The Bronx, New York