类金刚石碳（DLC）的测量

类金刚石碳（DLC）是一种无定形碳材料，其分子结构介于金刚石和石墨之间。DLC涂层用于提高耐磨性、耐化学性等，它被用作切削工具、汽车零部件、医疗设备、光学部件和许多其他产品的涂层。近年来，DLC涂层也被用于改善塑料瓶的气体阻隔性能。在本申请说明中，我们介绍了一个通过拉曼光谱测量DLC涂层塑料瓶的例子。此外，拉曼光谱可用于评估用于各种工具和磁盘的DLC的特性，并进行无损和非接触测试。Application Note020-AN-0023 Measurement of Diamond-Like Carbon (DLC)by Raman spectroscopy2/4Application Note Measurement of Diamond-Like Carbon (DLC) by Raman spectroscop y I nt r odu c tion Diamond -Li k e Car b o n (DLC) is an amorphou s carbo n mater i al t hat has an i n termediate molec ul ar structure between diamo n d and graphite . DLC coati n gs are us e d to improv e abras i on r e sista n c e， c hem ical r e sistanc e e tc.， it i s u s e d as a coat i ng f or cutt i ng tools， au t omotive compo n ents，medical equipment， opt i cal components and m any other products. In r ecent years， DLC coati n gs have also been used to improve the gas b ar r ier prope r t ies i n plastic bottles. This appl i c a tion n ote reports t h e analysis of DLC coa t ed plast i c bott l es usi n g Rama n spect r oscopy. NRS-5500 Ra m an S p ec tro meter Key words Diamond-L i ke Car b on， coat i ng， carbo n ， amorpho u s， po l yethylene terephthala t e Exper i mental Th e sampl e s m e asur e d were two types of p lastic bottl e with a vis u al a p pearan c e of d i ffe re nt colors as s h own i n F i gure 1.From this point f orwa r d， samples fr om colorless c l ear plas t ic bottles s h own i n Figure 1 are refe rr ed as “colored” (l eft) and samples f r om the "Clea r ”plast i c bottle (right) are refe rr ed as "u n colo r ed ". Figure 1 Mea su r e m e n t sa m p l e Measurements were made o f both t h e inside and ou t side sur f aces of eac h plastic bot t le (upper and l ower sur f aces as shown i n F i gure 1) and the Raman spectra were compared. T h e inst ru ment and meas ur ement paramete r s are as fol l ows. Measurement Conditions Main unit NRS-5500 Raman spectrometer Objective lens 100X Ex wavelength 532 nm Accumulation 2 times Exposure time 90 seconds R esul t s F igure 2 show the r esults of meas u remen t of b ot h the i nside and outside of the uncolored and colored samples . In t he case o f the uncolored sample， p o l yethylene te r e p hthalate (PET) peaks we r e obt a i n ed f r o m bot h i n s i de and outsid e measurements. For the colored sample， diffe r ent spectra were obtai n ed between t h e inside o u t side measurements. T h e diff e renc e spect ru m from t h e color e d samp l e i s s h own i n Figure 4. A database s e arch i d e ntifi e d t h e diff e ren t spec t r u m as DLC. PET wa s found on t h e o u ts i de of t h e colored sa m ple and on t h e i nsid e surface DLC was f ound i n add i tion to PET，t his co n f i r med that the i n s i de of t h e plast i c bott l e was coated wit h DLC. Figure 2. Mea su re m e n t o f u nc o lo r ed (Le f t ) an d colo r ed (Ri g ht ) s amples Fu rthermo r e， the quality of the DLC coati n g can be eval u ated f r om i ts spectr u m； the D band (sp3b o n ds i n the m aterial l att i ce) a n d G bands (sp² b onds in t h e mat e rial la tt i c e ) can b e d e convo l ved usi n g curve f itt in g as s h own in F i g ur e 4， f r om t h i s i t is possible to evalua t e character i stics suc h as abrasion r esistance fr om t h e peak posi ti ons， ha l f widths， peak rat i o etc. Figure 3. D i f f e ren ce sp e c tr um of co l ored s a m p le (In si de -O u t side) Figure 4. D an d G b an ds d e c onv o lu t ion Conclu si o n I n this ap p licat i on note， we in troduced an exa m ple of m easure m ent of a DLC coated plast i c bott l e by Raman spectroscopy. I n add i tion， Rama n ca n b e used to eval u ate th e characte ri stics of DLC used f or var i ous tools and magnet i c disks wit h non -d e stru c t i ve and non -contac t test i n g. Rema r ks The ty p ical thickness of DLC coa t i n gs on plastic bot t les is aro un d 10 nm to several te n s of nanometers. I n fu t u re， i t i s l i kely that DLC coat i ngs wi ll be made t hi n ne r i n o r der to reduce material costs. If the DLC t h ickness i s too t hi n， it may be di f fic u lt to d e t e ct by Raman spectroscopy. This tr en d i s s een not only for t he coatings on plast i c bott l es， but for the DLC indu s try as a whole. The measureme n t parameters for slit and aperture were as f ollows Slit： j25 um Ape r t u re： j40 um I n t his sample measureme n t ， D LC f i l m could be detected even using a l arge slit and aper t ure. But i n t h i s application not e， t h e re s u l t s of high spat i al resol ut ion ar e shown in orde r to improve t he qual i ty of DLC mate ri al d etection . The spectra i n Figure 2 s h ow tha t e v e n t h o u gh t h e plas ti c bott l es samples were made from the same material (p olyethyle n e te r ephthalate)， the b asel i nes were d i f f ere n t between the uncolored and colored samples. I n Raman spect r oscopy， the presence of slight amo un t of i mpur it ies c a n cause f luoresce n ce， i t is ass u med that a sl i ght di f ference occu r r ed i n the mate ri al due to a var i ation t h e production process . We recommend that t h e dedicated Carbon a n alysis p r ogram i s used fo r curve fi t t ing of multip l e spect r a (*.j ws spec tr um d ata fil e s). This program ca n be conv e nient l y u s e d to batc h process mul t iple d ata . Model Description P/N Remarks Main Unit NRS-5500 Raman Spectrometer 7119-J051A Laser： 532 nm In this application note a 100mW laser was used，howevergood sample measurementcan be made using the standard 50 mW laser. Accessories RXY-478B Automatic XYZ stage 6947-J478B RHG5-600B500 600 gr/mm grating 6947-J293A Measurement can be madeusing the standard grating(1800 gr/mm)， however werecommend the optional 600gr/mm grating with a widermeasurement range.