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Scribing wheel (SW) is an important tool for separating glass panels in thin-film transistor liquid crystal display industry. In this study, unlike the traditional SW completely made of polycrystalline diamond (PCD) or cemented tungsten carbide (c-WC), an alternative partially taking advantage of chemical vapor deposition diamond (CVDD) was newly developed. The fabrication of such unique sandwich-like CVDD-SW combined hot filament chemical vapor deposition (HFCVD), welding, and other machining processes. Both hard CVDD scribing edge and tough c-WC supporting layers contributed to SW structure. CVDD was prepared by adjusting the concentration of methane fed into HFCVD chamber. Morphological observation confirmed the reproducibility of microcrystal diamond (MCD), submicrocrystal diamond (SMCD), and nanocrystal diamond (NCD) diamond. Besides grain size, the existence of columnar structure, the nondiamond carbon content, the residual stress, and I(220)/I(111) ratio of CVDD films were characterized by scanning electron microscopy, Raman spectroscopy, and X-ray diffraction. Based on results, SMCD was predicted as the optimized CVDD for making a scribing edge. After three CVDD films were respectively integrated into SW, this prediction was supported by preliminary scribing test. Selecting Corning-1737 as the cutting object, among three CVDD-SWs and one self-made PCD-SW, only the scribing edge of SMCD-SW kept almost undamaged. The outperformance of our design was thus confirmed.

As a thermal interface material, thermal grease (TG) has been extensively applied to facilitate heat dissipation in electronic devices. Despite the superior thermal conductivity of diamond, researches on diamond-containing TGs remain rare. In this study, four kinds of TGs in which diamond served as essential filler were prepared and hot disk technique was applied to measure their thermal conductivity k(TG). After two unoverlapped particle sizes were selected, the volumetric filler content, terminal group, and viscosity of a polydimethylsiloxane (PDMS) matrix were modified in sequence. Based on the preferred recipe of a single-filler TG, two double-filler TG series were prepared by retaining the large diamonds and replacing the small ones by Al2O3 or ZnO, respectively. Depending on the content, it was found that diamond was not always the best choice for small filler. The highest k(TG), which was 23 times greater than the original k(PDMS), appeared in a ZnO-containing double-filler grease (=3.52 W/mK). The prediction for the maximum attainable thermal conductivity was preliminarily supported.