As the industry evolved toward higher rpm for high performance server drives, I managed a project to develop an ultrastable grease. I measured the oil oxidation chemistry to determine the grease base oil oxidation mechanism based on analytical measurements during accelerated life testing. Multiple additives were being evaluated to improve the thermal stability of the grease, which was time consuming, so I derived a kinetic model for synergistic effects of primary and secondary antioxidants and metal catalysis that minized the required number of life test iterations. My grease additive package formulation enabled the first 10krpm disk drives with steel ball bearings to be shipped.
Following ball bearings, fluid dynamic bearing were required for less vibration to enable smaller track spacing to increase areal data density. Initially the oil had a low viscosity but the vapor pressure was so high that the oil would evaporate. The bearing would dry out and fail. I developed a model and managed measurements to derive the thermodynamic relationship of vapor pressure and viscosity with oil molecular structure. My work led to the base oil type that is currently used in rotating magnetic storage products.
As an extension of the previous thermally stable grease project, I managed an project to develop thermally stable fluid bearing oil formulations. I assembled a unique test methodology for accelerated oil life testing to evaluate antioxidant and metial deactivator formulations. (Metal deactivator was needed because in some motors the stator was unplated sintered bronze.)
Along with the transition from steel ball bearings to fluid bearings it was discovered that the dielectric oil film of the fluid bearing accumulated charge which had previously been grounded through the ball to race contacts. I managed a project which spanned 3 decades to develop the ideal method to dissipate electric charge through the oil fluid bearing. Initially we evaluated an ionic conductivity additive which was highly conducting but caused a high discharge current in head disk contacts due to ionic charge separation across the bearing. I discovered that a polyaromatic antioxidant acted as a charge control agent through electronic hopping transport. However, the antioxidant is by design sacrificially decomposed to protect the oil, hence leading to drift of the motor oil electrical properties over time. Most recently, the novel approach to charge control in dielectric oils with minimal dielectric charge storage is achieved by grafting thermally stable aromatic or polyaromatic functionality onto the base oil molecule. One of these is featured on the TEK Data Systems logo.
I started out undergraduate school in electrical engineering at Union College in Schenectady NY. After about a year I found chemistry equally intriguing and decided to move towards chemical engineering in graduate school, which was not offered in the curriculum. I took all my electives in chemistry and mechanical engineering in order to have the basic requirements for application to graduate school in chemical engineering. This did not include the traditional unit ops, reactor design, and heat and mass transfer, which I had to catch up on during my masters in chemical engineering at RPI in Troy, NY. My masters thesis project was on electrokinetic effects on the deposition rate of colloidal particles for water filtration. I built a rotating disk apparatus and used it to characterize the effects of zeta potential on flux to a glass disk surface.
Towards the completion of my MS in ChE at RPI, I became interested in colloid chemistry, polymers, and surface science, and transferred to Carnegie Mellon University for my PhD studies in ChE. My PhD thesis project was on cross-flow migration of suspended particles in viscoelastic liquids for carbon black particle removal from recycyling automotive battery casings. I built a disk on plate apparatus and employed it to measure the particle migration in viscoelastic polymer solutions and compared the migration velocity with predictions from a second order fluid model.
Upon graduation I moved from Pittsburgh to the Bay Area, where I joined the IBM Research Division Almaden Research Center Department of Polymer Science and Technology. My industrial research initially focused on magnetic recording disk lubrication and wear, magnetic recording particle dispersion quality, and liquid crystal polymer melt rheology. During this time I characterized the tribology of all the commercially available recording disk lubricants, invented and implemented a new method to measure recording tape and disk particle dispersion quality, and discovered melt transesterification of Vectra E.
As the technology evolved, my research progressed to support the needs of the industry. I performed melt rheological characterization to determine the effect of gel content on electrophotographic toners to optimize print quality.
Magnetic recording disks were evolving from particulate to carbon overcoated thin film disks. I performed the first wear coefficient measurements on the several nm thick carbon overcoats. I set up a scanning microellipsometer instrument and carried out the seminal work on lubricant spreading which is critical to lubricant performance on magnetic disks.
I set up a lab with 12 disk testers with individual humidity and sub ambient pressure control. I managed a projects to characterize the effect of humidity on friction and wear and to measure tribochemical degradation of lubricant in contact recording.