Dear Dr. Siadati,

Surface morphology of the coated materials greatly affected by substrate preparation especially at the nanometer scale. substrate influence adhesion of coating to substrate, roughness, texture and grain size of coating. When comparing the influence of several parameters on the surface properties of coating are important, the substrate must be considered to have the same preparation and surface properties. all samples must be prepared just with grinding paper up to 5000 without consequent polishing with Al2O3 to obtain a comparable surface roughness.

Dear Dr. Siadati,

Surface morphology of the coated materials greatly affected by substrate preparation especially at the nanometer scale. substrate influence adhesion of coating to substrate, roughness, texture and grain size of coating. When comparing the influence of several parameters on the surface properties of coating are important, the substrate must be considered to have the same preparation and surface properties. all samples must be prepared just with grinding paper up to 5000 without consequent polishing with Al2O3 to obtain a comparable surface roughness.

the surface morphology of the substrate mainly depends on the method of coating you use to coat the graphite. Let e know which method of coating you are going to use.

surface roughness will also affect the bonding. mechanical bonding that come from Interlocking mechanism. For polishing, after polishing with paper up to 3000 or higher you can also use electropolishing, yo reduce residual stress due to polishing with grinding paper

Dear Bambang,

I agree with you, but with polishing the achieved roughness diferes in each sample because the nature of process. In grinding, a layer from surface is removed and the roughness of all the samples have to be equal. In polishing, the surface roughness crushed and due to non uniform applied force distribution at the surface, different roughness can be obtained. Furthermore, in electropolishing the current density distribution is non uniform too. With polishing, surface roughness will be different in each area of surface and also have much differences in each separated sample and we cannot conclude for comparison purposes.

Electroploishing is the final polishing technique. For any metal, this is the best method for polishing in the final stage. With suitable electrolyte for a particular metal, experimental parameters, like concentration & temperature of the electrolyte, current applied etc. need to be optimized so that you end up in the right region of polishing (i.e. neither under-polish, nor over-polish/etching). You can refer a good book on this topic: Specimen Preparation for Transmission Electron Microscopy of Materials, Peter J. Goodhew (Author), Publisher: Garland Publishing, 1984. There is a chapter on the topic.

Before you reach to the final stage, you need to use grinding papers starting from coarse ones to gradually finer ones, depending on the roughness of your starting surface.

For any nanometer coating, surface roughness of the substrate plays a great role. Surface morphology, surface roughness and hence the other physical properties of the coating will differ significantly depending on the substrate roughness as stated by Dr. Sajjad NK Abad. I don't have any data on thickness though. But I guess, it will also differ as adhesion of the sputtered ions with the substrate will differ with substrate roughness.

Dear sajjad

yes i gree with you, but I Think, it is difficult to get average surface roughness equal to zero. you can check the roughness in nano scale by AFM. The smallest roughness i have known is the surface silicon wafer. One of my student did deposing mono layer tetraether lipid on silicon substrat,.....it is found that the roughness is still there.

Find out the possibility using FIB to remove the surface to obtain the smallest roughness.

Dear Bambang,

You're right, silicon wafer have an average roughness about 0.2nm, and atomically smooth graphite have a smoother surface too. But the point of question asked here is how to prepare SS 316 or A6061 substrate surface for graphite deposition, I answered Dr. Siadati if he wants to investigate the effect of deposition parameters on the coated properties he need to prepare comparable substrates, as I tried other ways, it just can achieve with paper grinding. Proper paper grinding with a grit 5000 gives a surface roughness around 10 nm.

Dear mon ami Sajjad,.

Sorry,....my comment is not for you,...it is for our friends Mr. Siadati,.....

sorry,....it is often happen to me making a mistake.....

thanks,,,,i learns a lot from this forum.

Dear Bambang,

I do apologies, I had not supposed to offend your opinion, I just tried to drawn a clear perspective of surface preparation processes.

Based on all discussions, i would like to suggest that , if you are interested in testing the coated material strength, just go for 5000 grit paper grinding.

If you need to investigate the properties of the coating and the inetrface analysis, you need to go for electropolishing, where you can analyse the influence of coating parameters, interface bonding strength..etc..

But the selection of the method of preparation should be made by you only depending upon the method of coating you use..

Thank you all for great info. I conclude using 5000 grit on my samples whether SS of Aluminum for sputtering graphite on them.

Thanks again.