Dear Farooq,

can you tell the exact molecular formula? And the characteristic of the film, such as thickness, film continuity or any other. 

Dear chandan das.

Thanks for your guidance. I want to prepare this coating at less temprature

Dear Farooq,

I suggest you to use Reactive Magnetron Sputtering technique with a room temperature sample holder (a lot of literature is available, you can refer to hystorical works of swedish team led by prof. Berg for theoretical description) by using an already prepared AlCr mixed target with the exact chemical ratio you are interested or even by using 2 individual targets (1 of Cr and 1 of Al) and by tuning the bias current in order to tailor composition. Then, you need a mixed Ar-O2 atmosphere properly balanced and controlled in order to achieve the desired stoichiometric ratio Metal / Oxygen ratio. 

It seems hard to do but in truth these deposition processes are widely diffused in Lab and private coating service and well consolidated. 

You can obtain coating thickness from a few tens of nanometers up to 2-3 microns depending on substrate material and characteristics. 

Thanks, Dear Simone Vezzu for you valuable suggestions