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Surface topography, friction, scratching, wear and nanoindentation behavior of head slider materials were studied using atomic force/ friction force microscopy (AFM/FFM). Materials studied include polycrystalline Al 2 O 3 , Al 2 O 3 TiC (70-30 wt.%), polycrystalline MnZn ferrite, single-crystal MnZn ferrite and polycrystalline SiC. Al 2 O 3 is not used for construction of head slider but it was studied for comparisons with Al 2 O 3 TiC. SiC is a candidate slider material. The Al 2 O 3 TiC specimen exhibits the highest coefficient of microscale friction followed by polycrystalline MnZn ferrite, Al 2 O 3 , single-crystal Mn ferrite, Al 2 O 3 , single-crystal MnZn ferrite and SiC. Two phase Al 2 O 3 TiC exhibited higher microscale friction than a single phase Al 2 O 3 and polycrystalline MnZn ferrite exhibits microscale friction than a single-crystal MnZn ferrite. The local variation in friction force for Al 2 O 3 , polycrystalline and single-crystal MnZn ferrite was found to correspond to the lcoal surface slope (first derivative of the surface roughness profile). For Al 2 O 3 TiC and SiC specimen, the local variation in friction force at the scratches corresponds to the local surface slope. However, local variation over entire region corresponds to the different phases present on the specimen surface. Thus friction force imaging can be used for structural mapping of the surfaces. Directionality effects in the friction were studied on a microscale for the Al 2 O 3 specimen. Macroscale friction values for all samples are higher than microscale friction values as there is less ploughing contribution in microscale friction measurements. Microscratching/wear studies indicate that scratch and wear resistance of SiC and Al 2 O 3 are higher than that of the other specimens. However, Al 2 O 3 specimen shows the presence of porous holes on the surface that affect the wear performance. Al 2 O 3 specimen exhibits superior microscratch and microwear resistance than Al 2 O 3 TiC. Wear evolution for single and two phase materials was studied in detail. Nonoindentation hardness values found to be generally higher than that of microhardness data. Based on these measurements, coefficient of friction, microscratch and microwear resistance of singe phase materials are superior to that of two phase materials. |
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