First you need to know that all size of Fe powder particle does not react with air at room temperature, so you have to find that the powder you have whether it can react or not. And if it is reactive you can also keep it in air tight jar/vessel. You can also place some silica gel crystals near by so that the moisture in air can be taken up by silica gel and will not affect the Fe-powder.

Dear Akeshwar Singh Yadav

The particle size of our Fe powder is about 20 micron. I want to protect this powder from oxidation and then use it in a water solution so i am searching to find a water soluble material to protect my Fe powder

20 micron powder will not get oxidize at room temperature, not even upto 200C (at least for 2 hrs). This I know because of my experience with 20micron Fe powder.

Dear Akeshwar

Do you mean that Fe powder will not oxidize at room temperature for 2 hours? I have to protect this powder at least for 10 days.

I mean that 20 micron powder will not oxidize at room temp. you can store it for years.

at 200 degree Celsius temperature it will not oxidize for at least 2 hours.

Dear Akeshwar Singh Yadav

thanks a lot for your help.

I made iron powder by dissolving oxidized mill scale, purifying, crystallizing and then reducing in hydrogen and found it difficult to prevent oxidation in due course. I used the left over powder by making sparklers.