I have searched the forum, but have yet to find a really good discussion of cementation, past "cement with copper, never cement with silver". I understand the electromotive series, and the generality of the process of reduction through transfer of electrons. Where my knowledge falls off are the conditions, a true understanding of contraindications, etc.
So I'll make the following statements, they could be right, they could be wrong...please correct or discuss as necessary. I will come back and edit, in red, any corrections that need to be made so as to not mislead people in the future.
1) In general, I believe that if one wants to cement fast, but not complete, a more concentrated solution will be the ticket.
2) If one wants to cement complete, but not fast, a less concentrated solution will work.
3) The use of heat, increases the speed of cementation, and free acid consumption.
4) Free acid is a necessary component of the cementation reaction.
5) As concentration of metal ions decreases, the ORP of the solution falls, increasing the likelyhood of ion exchange in cementation reaction. I know that pH also comes in to play here, but I don't fully understand how.
So I'll make the following statements, they could be right, they could be wrong...please correct or discuss as necessary. I will come back and edit, in red, any corrections that need to be made so as to not mislead people in the future.
1) In general, I believe that if one wants to cement fast, but not complete, a more concentrated solution will be the ticket.
2) If one wants to cement complete, but not fast, a less concentrated solution will work.
3) The use of heat, increases the speed of cementation, and free acid consumption.
4) Free acid is a necessary component of the cementation reaction.
5) As concentration of metal ions decreases, the ORP of the solution falls, increasing the likelyhood of ion exchange in cementation reaction. I know that pH also comes in to play here, but I don't fully understand how.
