Described herein is a protective coating composition that provides erosion and corrosion resistance to a coated article (such as a chamber component) upon the article's exposure to harsh chemical environment (such as hydrogen based and/or halogen based environment) and/or upon the article's exposure to high energy plasma. Also described herein is a method of coating an article with the protective coating using electronic beam ion assisted deposition, physical vapor deposition, or plasma spray. Also described herein is a method of processing wafer, which method exhibits, on average, less than about 5 yttrium based particle defects per wafer.