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The current trend in the magnetic storage industry is the reduction of the slider size and the height at which the slider flies over a rigid disk. Lower flying heights are achieved by miniaturizing sliders and reducing the normal load. In this paper, force scaling criteria are determined for 3370 and 3370K sliders that are dynamically loaded or operated in contact start/stop mode. Two forms of the generalized Reynolds equation (the first-order and continued fraction formulations) are incorporated into the analysis. The new scaling equation relates the steady-state flying height to design and operating parameters such as the disk velocity, normal load, ambient pressure, and the shape and dimension of the slider rail. The resulting quadratic equation contains two slider design dependent parameters which are calculated from two full scale numerical solutions to the generalized Reynolds equation for the slider design of interest. The new scaling equation accurately fits numerical and experimental results over an extremely wide range of ambient pressures, normal loads, disk velocities, and slider size reduction. The utility of the scaling equation is that it can rapidly and accurately predict the load required to obtain a desired flying height at a given disk velocity for any slider geometry. The scaling analysis also has the ability to qualitatively account for surface roughness effects. The equation could be applied to the design of contact recording devices, if surface roughness effects could be quantitatively incorporated into the analysis.

A study was done on the concentration and flow orientation of rodlike gamma-Fe2O3, rodlike CrO2 and platelike Ba-ferrite particles. Results show a good agreement of rheomagnetic (RM) measurements for the three particle suspensions with vibrating sample magnetometer and TGA results. These results suggest that the RM device is applicable for on-line process control and measurement of particulate magnetic recording media using Ba-ferrite particles as well as rodlike gamma-Fe2 3 and CrO2 during the early coating stages.

To accommodate pseudo-contact and contact recording, new slider materials for high-performance heads must be developed. A new candidate for an advanced slider material is SiC. To compare the tribological properties of SiC with [Al.sub.2][O.sub.3]-TiC (AlTiC), today's standard thin film head slider/wafer material, heads with SiC dummy sliders have been manufactured and compared to an AlTiC slider. All test heads were subjected to both dynamic friction testing as well as an AFM mapping comparing surface topography and nano-friction. The friction for SiC heads was observed to be highly dependent on its surface roughness and may start out even higher than AlTiC. However, the increase in friction over contact time of SiC is much shallower than for AlTiC, therefore the long term friction and wear performance of SiC sliders are superior.

Future disk files will operate at lower flying height, thus increasing the possibility of asperity contacts. Conventional tests include sliding (Pin-On-Disk or Slider-On-disk), flying (flyability tests), or Contact Start/Stop modes of operation. A Novel Accelerated Wear Test (NAWT) was developed to produce intermittent asperity contacts. The NAWT operates in a mixed sliding and flying region, and is designed to operate in a zone of interaction where a significant number of asperity contacts occur. The NAWT uses an Acoustic Emission sensor to detect asperity contacts. The signal is processed by Fast Fourier Transform to detect significant increase in the frequency and severity of the contacts. The new apparatus and procedure are presented along with illustrative results.

A study was conducted to investigate the rheological properties as well as dispersion stability of magnetorheological fluids (MR) under applied magnetic fields. The result showed that although the MR properties such as yield stress and shear viscosity of CI-PVB [poly (vinyl butyral)] based MR fluids, changed slightly compared with those of the pristine CI based MR fluids, the dispersion qualities were noticeably improved.

Studies the spreading of perfluoropolyalkylether thin films on amorphous carbon surfaces by scanning microellipsometry. Types of perfluoropolyalkylethers with the same main-chain structure and various molecular weights used in the study; Spreading of binary blends of Zdol-Zdol, Z-Z and Zdol-Z.