Embodiments of the invention provide a thermal spray method of forming a protective and porous coating over desired surfaces. Further, embodiments provide a thermal arc spray method, such as twin wire arc spray, to coat the surfaces. The invention may refer to using Aluminum and Silicon alloy in a twin wire arc spray method, to create sacrificial and protective coatings on the surfaces, such as substrates and machine parts. Machine parts may be, for example, of sputtering system. The method may utilize a predefined range of Silicon to be alloyed with Aluminum to improve the physical properties of the Aluminum, and further avoid damages to the coated surface, such as de-lamination and flaking of the coatings and coated surfaces. Additionally, generation of defects during a sputtering process may be efficiently reduced.