STP1278

    Laser Surface Melting of Carbide Coatings and Their Tribological Behavior

    Published: Jan 1996


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    Abstract

    The effect of laser surface-melting on the friction and wear of detonation gunsprayed (W, Ti)C-Ni (tungsten and titanium carbide-nickel) and WC-Co (tungsten carbide-co-balt) ceramic coatings on AISI 1044 steel and Ti-6Al-4V substrates was studied. The coated surfaces were melted using a 1.5 kW CO2 laser with a power setting of 1.4 kW and travel speed of 0.01 m/s. The changes in microstructure and microhardness due to the laser treatment were examined. The melted layers were found to be full of dispersed pores that started 65 to 70 μm below the surface. The surface hardness of (W, Ti)C-Ni coated specimens either decreased or remained constant after surface melting; however, the hardness of WC-Co coated specimens increased. Dry sliding friction and wear tests were conducted in a block-on-ring wear tester, with the coated specimens as block specimens and hardened tool steel as the ring specimen. The width of both the ring and the block was 6.35 mm. The test conditions were 4 m/s sliding speed and 4.9 N load. It was found that as a result of laser treatment the wear resistance of WC-Co coating increased, but that of (W, Ti)C-Ni coating decreased. Scanning electron microscopy of the wear surfaces showed that the micromechanisms of wear were cracking and material disintegration from the edges of the cracks and holes.

    Keywords:

    carbide coatings, laser treatment, friction properties, wear testing, microstructure, hardness testing, wear mechanisms, surface coatings, surface treatments


    Author Information:

    Bahadur, S
    Professor and graduate student, Iowa State University, Ames, IA

    Yang, C-N
    Professor and graduate student, Iowa State University, Ames, IA


    Paper ID: STP16101S

    Committee/Subcommittee: G02.50

    DOI: 10.1520/STP16101S


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