Ni-based composite coatings with different nano-TiN additions are produced by laser cladding on 38CrMoAl substrate. The influence of nano-TiN on the mircrostructure and properties of the coating is investigated through X-ray diffraction

scanning electron microscopy

electronic probe

Vickers hardness tester

and friction wear testing machine. Results show that the coatings consist of γ-Ni

Ni3B

M23C6

and TiN phases

exhibiting hypoeutectic morphological characteristics. As the addition of nano-TiN is 5.0 %

the primary γ-Ni dendrite is coarsed obviously

whose number is increased. However

as the addition of nano-TiN is more than 5.0 %

the primary γ-Ni dendrite shows decrases in size and number with increasing the addition of nano-TiN

whose growth morphology changes from equiaxed dendrite to columnar dendrite. Meanwhile

the number of the micron-sized TiN particle

growing in form of agglomeration

is also increased

and its distribution becomes more uniform. For this reason

the average hardness of the coatings gradually increases with increasing the addition of nano-TiN as a whole

and the tribological perperty is best as the addition of nano-TiN is 15%

showing 8.7% and 32.3% decrease in friction coefficient and wear volume as compared with the coating without TiN addition

and a 7.0 % increase in average hardness.