Metal-matrix composites that consist of a ductile metal-matrix and hard ceramic particles are often used as materials of choice for protection against solid particle erosion. In this study, a model Ni-Al O system was chosen to analyze the effect of hard second phase 2 3 particles on erosion resistance. This system consists of hard Al O particles dispersed within a ductile Ni matrix. Two processing 2 3 Ε½ . techniques were used to fabricate the Ni-Al O composites. First, a hot isostatic pressing HIP technique was used to produce bulk 2 3 Ni-Al O alloys. These composite samples contained 0-45 vol.% of Al O with an average particle size of 12 mm. Second, an 2 3 2 3 Ε½ . electrodeposition technique was developed and Ni-Al O coatings with various volume fractions of Al O 0-39 vol.% were produced 2 3 2 3 on a pure Ni substrate. In contrast to the bulk powder composites, the electrodeposited composites contained much smaller Al O 2 3
Ε½ . particles f 1 mm . Erosion testing was conducted at impact angle of 908 using angular alumina. It was found that for both type of composites, an increase in Al O content led to an increase in erosion rate of the composites and pure Ni showed the best erosion 2 3 resistance. However, the electrodeposited Ni-Al O alloys exhibited better erosion resistance than the powder processed Ni-Al O 2 3 2 3 alloys. For erosion test conditions used, the smaller Al O particles in the Ni matrix were more beneficial in terms of erosion resistance 2 3 than the large Al O particles.