Concentration change of acid in anodization

Sir
I want to know if there is any change in the concentration of acid in the process of anodization.I performed an experiment in 0.3M oxalic acid but somehow my foil is lost.
Again doing the anodization with the same acid did'nt give me result.why?At the same time there is temperature increase.
Sir if you give the reation of anodization with heat loss, it will be a great help to me.

I do not think that you have done your research well, but that is just a guess from the information provided.
1. Anodizing is the controlled oxidation of some of the parent metal to an oxide. The acid will eat the oxide at a rate dependent on many things, concentration and temperature are the most important ones for a new solution.

2. Anodizing generates heat, that is why you must have a temperature control mechanism that is effective. Solution flow is required, be it air or pump or mechanical.

I will guess that your temperature was a few degrees higher on the first try and /or you parts did not get a proper voltage/amperage to anodize. Racks can be critical and dirty contact points make a massive difference.