Large sized cubic BN reinforced nanocomposite with improved abrasive wear resistance deposited by cold spray

• Large cBN reinforced nanocomposite coatings were developed for high wear resistance.
• Coatings were prepared via cold spraying mixtures of cBN and nanocomposite powders.
• Optimal wear resistance (100% increment) was gained by involving 20 vol.% of cBN.
• Large cBN particle plays an important role in improving the wear resistance.

In this work, large sized cubic BN (cBN) reinforced nanocomposites are prepared by cold spray deposition of blended powder mixtures of mechanically alloyed 40 vol.% cBN–NiCrAl nanocomposite particles and large sized cBN particles. Deposition behavior of the blended powders, microstructure and mechanical properties including hardness, fracture toughness and two-body dry abrasive wear behavior of the sprayed composites, are investigated. Results show that dense composites with large cBN particle content of 13–20 vol.%, depending on composition of the spray powders, can be obtained. Declining deposition efficiency is detected as increasing large cBN content due to the gradually enhanced sand blasting effect. Increasing content of large cBN in spray powder results in an increment in hardness and a decrement in fracture toughness. Abrasive wear resistance of the 40 vol.% cBN–NiCrAl nanocomposite is doubled by incorporating 20 vol.% of the large cBN particles. Worn surface morphology observation indicates that the improvement is due to the shielding effect of the large protruding cBN particles against SiC abrasive. Material removal mechanism of the sprayed composites during abrasive wear test is also studied.

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