Coatings film thickness measurement

General chemical resistance can be classified as short-, medium-, or long-time resistances. Changes in the coating are assessed visually. For standards, see Table 1 ( Chemical resistance ). Apparatus film thickness measuring equipment. 

Coating thickness was measured both wet and dry. Wet thickness measurements were taken using a Gardner s Company Precision Hot Cake, which can measure between 125 and 500 pm films with a 2a uncertainty of +10%. Dry film thickness measurements were taken using an ElektroPhysik s Exacto FN gauge, which can measure between 0.1 and 2000pm with a 2a uncertainty of 3%. 

Methods. Polyamic acid in NMP was spin-coated onto a Si or Quartz wafer (diameter = 2.25 inches) coated with Cr, and then cured to polyimide at 400 °C. The purpose of the 500-750-A-thick layer of chromium is to enhance wettability and to give good reflectance to the Quartz wafer. Kapton H (PMDA-ODA) and Upilex S (BPDA-PDA) films were employed for gravimetric analysis. Around 5-um thick layers were used to measure the thickness change. The 100-1000-A-thick layers were employed to obtain XPS and ER IR spectra. The samples for contact angle measurement, XPS and ER IR were dried under vacuum at ambient temperature for 12-24 h and the samples for gravimetric analysis were dried at 85 °C for 12 h. The samples for film thickness measurement were fully re-cured to polyimide. 

Typical procedures of the bending beam experiments were as follows. Resin coatings were applied to one side of a clean quartz strip by spin-coating from an appropriate solvent at 2000 to 8000 rpm for about 30 seconds. Coatings were then evaluated for uniformity, and acceptable beams were then inserted into the bending beam apparatus. Stress measurements were taken during temperature ramps and holds. The specific cure schedule followed for each material depended on the manufacturers recommendations or the results of microdielectric cure studies (lfi.). Upon completion of all stress experiments, the beam was removed and the film thickness measured by an Alphastep profilometer. The quartz beams were 82 2 pm thick,... 

We present an XPS study of the interfaces P(VDF-TrFE)/Al and P(VDF-TrFE)/PEDOT PSS. As copolymer, we used P(VDF-TrFE) in a molar ratio of 70 30. The material was delivered as film from Piezotech SA, France. As solvent for spin coating, we used 2-butanone. We prepared different concentrations (as wt% P(VDF-TrFE) in 2-butanone) to investigate the dependence on layer thickness. After spin-coating at 6000 rpm, the film was annealed at 135 °C for 2 h to improve the crystallinity of the aXX-trans conformation, the so called P-phase [21]. The thickness of the spin-coated film was measured using a Taylor Hobson (Talystep) profilometer. 

The thickness of the polymer coatings was determined as follows. Polymer films were spin cast (15) from a MDI/ED/PTMO polyurethaneurea of known composition. The film thickness, measured by a micrometer, was found to correlate linearly with the height of the 1600 cm peak (v(C C) benzene ring), thus allowing determination of a Beer s law extinction coeffecient for the mass fraction of benzene rings in these polymers. Transmission spectra of the dip coated IRE s were obtained, and the polymer thickness determined assuming that the Beer s law extinction coefficient was unchanged on these thin films. 

Figure 14.12. Film-thickness measurements using characteristic x-rays emitted by the coating or the substrate.

Measurement of Film Thickness. An accurate definition of film thickness can only be given if the coating has even upper and lower surfaces and a defined density. In practice, neither the surface of the coating nor that of the substrate is even. Surface irregularities and density variations influence the results of each test method in a specific way. Results of different tests performed on the same sample may therefore differ substantially. Results of film thickness measurements therefore always have to be quoted together with details of the measurement method and instrument used [9.10], [9.11]. A survey of methods used to measure paint thickness is given in ISO 2808. 

These polymers were dissolved in spectroscopic grade dioxane, and then filtered through a 0.45 pm membrane. The solutions were then spin-coated onto glass slides. The film thickness was controlled to 0.2-2.0 pm by adjusting the solution concentration and spin speed. The spin-coated films were then dried under vacuum for 24 h at 40-50 and stored in a desiccator until fiirther studies. Since the sulfonated and carboxylic substituted polyazophenols were water-soluble, deionized water was used as the solvent to dissolve these polymers (pH 11 water was used for the carboxylic substituted polyazophenol). The solutions were also filtered through a 0.45 pm membrane and the films were fabricated on glass substrates at temperature of 70 °C. The thickness of all spin-coated films was measured by using a Dektak IIA surface profilometer. 

In conclusion, for the PFOM film thickness measurement, the non-carbon-over-coated silicon wafers can be used to monitor the thickness of PFOM being deposited on the air bearing surface as long as the presence of an offset in the deposited film thickness between the two types of substrates is taken into account. 

For wet film thickness measurement of paints and varnishes (i.e. before drying of the freshly applied coating), it is common to use mechanical wet film thickness gauges, which involve pressing or rolling a calibrated scale onto a wet film. 

The experiments reported here make use of the Thin Film Colorimetric Interferometry technique for film thickness measurement. In this technique, 3 X 8 bit SXGA still pictures are after transformation from RGB to CIELAB colour space converted to the film thickness map using appropriate colour/film thickness calibration curves. They are obtained from Newton rings for static contact formed between the steel ball and the glass disc coated with the chromium layer only. During several last years the accuracy and resolution of TFCI has been improved and it is now able to measure film thickness to within 1 nm [13]. 

K. C. Mittal, ed., Mdhesion Measurements of Thin Films, Thick Films and Bulk Coatings, ASTM STP, Philadelphia, Pa., 1978, p. 640. 

Measure the dry-film thickness of each coat over a representative area and ensure that the specified film thickness has been attained. 

The hardness and abrasion resistance of anodic coatings have never been easy properties to measure, but the development of a British Standard on hard anodising has made this essential. Film hardness is best measured by making microhardness indents on a cross-section of a film , but a minimum film thickness of 25 tm is required. For abrasion resistance measurements, a test based on a loaded abrasive wheel , which moves backwards and forwards over the film surface, has improved the sensitivity of such measurements. 

Currem field characteristics measured wiih conjugated polymers sandwiched between an indium-tin oxide (ITO) anode and an aluminum cathode are usually hole dominated and are, consequently, appropriate for testing injection/lransport models for the case of unipolar current How. Data shown in Figure 12-1 refer to injection-limited currents recorded on typically 100 nm thick spin-coated films of derivatives of poly(y d/"fi-phenylenevinylene) (PPV) and a planarized poly(/ /" -pheny-leue) employing a Keilhley source measure unit. The polymers were ... 

The apparatus for the PFAM film coating on the slider surface is shown in Fig. 1 (a). The film thickness was measured by the TOF-SIMS as shown in Fig. 1 (b). It used a pulsed primary Ga+ ion beam to impact the surface of the PFAM film with an inset energy of 15 keV, an extractor current of 2 fj,A, beam current of 600 pA, a pulse width of 17.5 ns, and a frequency of 10 kHz, respectively. The positive TOF-SIMS spectra on the slider surface is shown in Fig. 2 where the peaks at m/z 31, 50, 69, 100, and 131 in Fig. 2(a) correspond to the positive secondary ion fragments of CF+, CFj, C2F4, and C3F5, respectively. The peak at m/z 469 apparent in Fig. 2(b) corresponds to the ion C12H7F 15O2H+ which is the characteristic ion of PFAM molecules. Therefore, the positive TOF-SIMS spectra demonstrates the existence of PFAM film [24,25]. The thickness of the PFAM film can be determined... 

Size measurements have also been collected for film thicknesses and bead sizes on the electron microscope [79-81]. One example is the study of the relationship between film thickness and the size and mass of a bead in a fluidized-bed unit [79]. The bead diameter and film thickness were determined by SEM and correlated to dissolution data. It was found that larger beads received thicker coatings and exhibited slower release rates than the smaller beads. 

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