An investigation on the feasibility of sputtering a diamond block into a specially designed three-dimensional cutting tool shape using a focused ion beam (FIB) was carried out. The ion-sputtered removal rate, surface morphology and sputtered feature accuracy were evaluated with respect to the FIB parameters such as ion current and angle of ion incidence through sputtering pockets on the top surface of a diamond substrate. A single crystalline diamond tool, with 25 µm length in the cutting edge and smooth face quality, has been successfully fabricated by using a FIB. These excellent tool characteristics are proven in the results obtained from the machining experiments done on the ultra-precision machine.

Ultrathin (< 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in 2 . These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the "macroparticle" issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system -a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using Sfilter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested. Index Terms: diamond-like carbon, cathodic vacuum arc, macroparticle filtering, magnetic storage, carbon overcoats 3 I. INTRODUCTIONUltrathin (< 5 nm) hard carbon films are used as protective overcoats on hard disks and readwrite heads. The tribological properties of the head-disk interface are not only of mechanical but also of chemical nature: the overcoat should protect the magnetic layers against wear and corrosion [1, 2]. The areal density of information stored in disk drive products increased at an amazing rate of over 65% for many years rate, and continues to accelerate to even greater rates [3]. To accomplish this, the "magnetic spacing" between the magnetic layers of the disk and read/write sensor of the head must continue to decrease. The magnetic spacing includes the overcoats, lubrication, and the fly height. Thinner overcoats allow the read-write head to be closer to the magnetic layer of the disk, and hence, the size of individual bits on the disk to be smaller. As we work toward an areal density of 100 Gbit/in 2 , the magnetic spacing approaches the sub-10-nm regime (pseudo-contact recording) and overcoat thickness must shrink to 1-2 nm. Overcoats currently used are sputtered or ion-beam deposited diamond-like carbon films, typically doped with hydrogen or nitrogen. They cease to provide acceptable levels of corrosion protection when the film thickness is less than 5 nm.Overcoats need to be tough (hard and elastic), chemically inert, pinhole-free, and compatible with the lubricant. The challenge of ultrathin film synthesis is to make the films as thin as possible and still continuous, as opposed to an assembly of islands.Nucleation and growth of ultrathin films is a field of intense research. For carbon, it is well known that films that are rich in sp 3 (diamond) bonds should be grown in a kinetic mode at low temperature (less than 200°C, preferably room temperature), with film-forming carbon atoms or ions having an energy of about 100 eV. This energy is optimized for subplantat...

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The tribo-chemical interactions between the slider and the hard disk surface strongly influence the performance properties of a disk drive. To study these interactions, uncoated and carbon coated sliders were subjected to various wear tests using different disks. After the wear, the test slider surfaces were studied by photoemission electron microscopy (PEEM) using tunable x rays produced by a synchrotron. Using PEEM, one can identify the elemental and chemical state of the surfaces with a high spatial resolution. It was found that wear reduces the thickness of the carbon coating in some local areas of the slider surface. In particular, the coating was removed on elevated areas and in scratches. Scratches were found on the rails of the carbon coated and uncoated sliders after wear that showed the accumulation of a degraded (oxidized) lubricant which was transferred to the slider from the disk. It was also possible to analyze the chemical composition of the debris found on the slider surface. In the present case, the debris had the same chemical composition as the carbon coating of the slider.

A study was carried out to understand the physics of micro-scale mechanical machining (henceforth referred to as ‘micro-machining’) with a micro-size tool using a five-axis ultra-precision machine. A micro-size single crystalline diamond (SCD) tool with sharp cutting edges fabricated by a focused ion beam (FIB) was employed to orthogonal-machine four materials (three polycrystalline metals with various grain sizes and one amorphous metal plating material). Since the wealth of knowledge of macro-machining cannot be successfully used in micro-machining, this study contributes to the understanding of the physics of mechanical machining with micro-size tools.

Tribo-chemical studies of the head/disk interface (HDI) were conducted using hydrogenated CHx carbon disk samples coated with perfluoropolyether ZDOL lubricant. The studies involved drag tests with uncoated and carbon-coated Al2O3-TiC sliders and thermal desorption experiments in an ultra-high vacuum (UHV) tribochamber. The friction and catalytic decomposition mechanisms as well as the thermal behavior of ZDOL are described, and data demonstrating the chemical reactions of the lubricant and carbon overcoat are also presented. During the sliding at the carbon-coated slider/ZDOL lubricated CHx disk interface, frictional heating is the primary decomposition mechanism of ZDOL. [S0742-4787(00)01902-0]

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