Components of semiconductor processing apparatus are formed at least partially of erosion, corrosion and/or corrosion-erosion resistant ceramic materials. Exemplary ceramic materials can include at least one oxide, nitride, boride, carbide and/or fluoride of hafnium, strontium, lanthanum oxide and/or dysprosium. The ceramic materials can be applied as coatings over substrates to form composite components, or formed into monolithic bodies. The coatings can protect substrates from physical and/or chemical attack. The ceramic materials can be used to form plasma exposed components of semiconductor processing apparatus to provide extended service lives.