A method for forming an acetabular shell includes providing a working surface such as a mandrel, and spraying the working surface with a first layer of material having a first composition such as aluminum oxide. After a suitable thickness is generated, the spray composition is gradually changed to other compositions having desired particle sizes and distribution. In one example, the composition is changed to a mixture of aluminum oxide and titanium oxide and/or titanium. As thickness builds up, the relative amount of aluminum oxide is decreased such that the composition is all titanium and titanium oxide. After a desired thickness is generated, the acetabular shell is extracted off the mandrel.